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abdominal pregnancy           An ectopic pregnancy located in the peritoneal cavity, or abdomen, usually having undergone implantation in the fallopian tube as a tubal pregnancy, then continuing to grow after the tube eventually ruptures. Rare in countries with ready access to medical care, as considerable symptoms have to have been ignored (and survived) during the tubal rupture part of the process. The fetus can grow almost to full term, but delivery of a live baby (delivered by operation) has never been reported. Sometimes (fancifully) thought of as a way men might bear children!

abnormal forms        An estimate of the percentage of spermatozoa that have an abnormal shape of the head, mid-piece or tail. Part of the routine sperm count.

abnormality   A departure from what’s normal -- in a more or less exact medical sense. An abnormality can be quantitative (or measurable with a number), qualitative (not measurable but still apparent or obvious), or a matter of timing (temporal). Statistically, we define an abnormality as signifying either a measurement or a yes-or-no quality that is outside what, for example, 90 or 95 or 99 percent of the population exhibits (see also statistical significance). It’s a word without added value, unlike defect, for example, which has a negative connotation. So if you want to avoid a gratuitous, negative effect it’s preferable, using this example, to say “birth abnormality” instead of “birth defect”. See also anomaly.

abortion         Strictly, synonymous with spontaneous abortion or miscarriage. Loosely, an induced abortion for early termination of pregnancy.

abortion rate See miscarriage rate.

abortion rate See miscarriage rate.

absolute infertility   Synonymous with sterility, or 100 percent infertility; also called complete infertility. See also relative infertility.

absolute risk Your actual chance of having something or being affected by something (so it does not usually mean “absolutely” in the sense of “one hundred percent’, as in absolute infertility). Usually given as a ratio, proportion or percentage: for example, the (absolute) risk of having at least some visible endometriosis for a woman in her 40s is about 20 in 100, or 20 percent; the chance or the risk of pregnancy each month for a normal young couple (normal fecundability) is also about 20 percent, usually expressed as 0.2 (i.e. as a proportion); the risk of a woman developing cancer of the ovaries by the time she reaches her seventies, in North America, Europe or Australia, is about 1-in-90 (or about 1.1%).

accountability           The sequel to responsibility, in which responsibility for the making of a decision continues to rest with the decision-maker as the effects or consequences from the decision unfold.

acrosome reaction    If the acrosome is a balloon-like crash-helmet for the mature spermatozoon, the acrosome reaction is the bursting of that balloon, releasing enzymes that digest a path for the highly motile sperm (after capacitation) to push through the zona pellucida into the perivitelline space, where it can directly fertilize the egg.

acrosome        Consider it to be the mature spermatozoon’s crash-helmet, present over the sperm head until the successful sperm binds to the coating of the egg known as the zona pellucida; imagine it to be like a balloon into which your fist is pushed (the fist being the sperm’s head) -- bursting only when bound like Velcro to the zona (see acrosome reaction).

acute   Medically, means sudden and quick. An acute inflammation is usually red, tender and may form pus. Opposite to chronic.

adenohypophysis      The glandular part of the pituitary gland, lying toward the front, so in medical speak called the anterior pituitary. Produces follicle stimulating hormone, luteinizing hormone and prolactin. Other hormones include hormones that: (1) cause normal childhood growth (growth hormone), (2) drive the thyroid gland (thyroid stimulating hormone, or TSH), and (3) drive the adrenal gland (adrenocorticotropic hormone, or ACTH). See also hypothalamus and neurohypophysis.

adenomyoma See adenomyosis.

adenomyosis  An abnormal condition of the uterus in which glands from the endometrium grow into the muscle of the wall of the uterus (the myometrium), causing local or general enlargement of the uterus, pain with periods, and perhaps heavier periods. A localized area of adenomyosis is called an adenomyoma and can be hard to distinguish from a fibroid on transvaginal ultrasound, although an increase in the serum CA 125 antigen level can point to the correct diagnosis. Unlike a fibroid it is not easily removed at surgery, because it’s not clearly separable from surrounding tissue. There’s no satisfactory long term treatment for adenomyosis: hysterectomy may be chosen if symptoms are bad enough. GnRH-agonists give just temporary relief.

adhesions       Scar tissue, in particular between the serosa (surface lining) of abdominal or pelvic organs in the peritoneal cavity, which can interfere with the access the fallopian tube has to the ovary at ovulation. Adhesions can be thin and transparent (sometimes called filmy or Grade 1), a little like thin plastic wrap; thicker, and containing more scar tissue and blood vessels (Grade 2); or thick, dense and tough (Grade 3). Adhesions are caused by infections, endometriosis or a previous operation. Not all adhesions are important: it depends on where they are. See also intrauterine adhesions. The treatment of adhesions requires microsurgery, and there are special steps that have to be taken to stop them coming back again.

adrenal gland            A paired gland lying above each kidney, responsible for the essential hormone cortisol. Equally important with the ovaries in producing androgens in women. See also serum 17-hydroxyprogesterone.

AFP     See alpha fetoprotein.

AI        See assisted insemination.

AID     Artificial insemination, donor (or assisted insemination, donor); see donor insemination.

AIDS  Acquired immune deficiency syndrome (see HIV).

AIH     See assisted insemination, husband.

alleles Because genes come in pairs, one on each of the chromosomes that make up a chromosome pair, the two genes of the pair are not always identical. The many
different forms that a particular gene can take (and still function, for better or for worse, as a gene within that gene’s job description) are referred to as its alleles. If the alleles are identical, you are homozygous for that gene; if they are not, you are heterozygous. Abnormal alleles cause genetic disease or disability: if one allele is enough to cause abnormality then the gene is dominant (inherited with dominant inheritance) and the abnormality is present in the heterozygous and the homozygous state; if two alleles are needed to cause abnormality, then the gene is recessive (inherited with recessive inheritance) and the abnormality is present in the homozygous state and in a state where the two alleles are different but both are harmful (called compound heterozygosity. In the case of alleles found on X-chromosomes (see sex chromosome) but not on Y-chromosomes, which are smaller, a recessive gene will be unopposed in males (and so will act as a dominant gene), whereas female carriers of the allele will be unaffected except in the extremely unlikely event that they inherit (or gain by mutation) a second abnormal allele; this mode of inheritance is called sex-linked recessive inheritance.

alpha fetoprotein      A form of albumin (a protein in the blood) produced only by the fetus, but crosses the placenta and so is detectable in the mother’s blood (measured with a serum alpha fetoprotein, as well as being usefully measured in amniotic fluid obtained by amniocentesis. Detectable in higher than usual concentration with certain open abnormalities involving the fetus’s brain and spinal cord (namely anencephaly and spina bifida). Present in lower than usual concentration when there is a trisomyin the fetus, such as Down syndrome (or trisomy 21), trisomy 18 or possibly Klinefelter syndrome -- screening for all of which can be done with a triple test.

amenorrhea   Absent menstrual periods, either because of absent ovulation (anovulation) or because of absence of, destruction of, or obstruction to the menstrual flow from the uterus, such as with intrauterine adhesions (when it’s known as Asherman’s syndrome).

AMH   See anti-Müllerian hormone.

amniocentesis           Sampling the fluid from the amniotic cavity after about 14 or 15 weeks of pregnancy. Cells from the fetus can be set up in culture for a karyotype, or for special diagnoses can be examined more quickly by fluorescent in situ hybridization (FISH), comparative genomic hybridization (CGH) or by polymerase chain reaction (PCR). Other substances in the amniotic fluid (such as alpha fetoprotein, or AFP) can be measured to indicate whether the fetus is normal or not.

amnion           The membrane and cavity that encloses the developing embryo and fetus in fluid (essential for all vertebrates that reproduce out of the sea), cushioning the embryo and fetus from the effects of pressure. Unlike the chorion, contains cells that originate from the fetus itself.

amniotic cavity          Cavity enclosed by the amnion, which grows from the embryo within the gestational sac, gradually catching up with it in size by about 14 weeks, when the amnion and chorion fuse, and after which amniocentesis becomes practicable. See also amniotic fluid.

amniotic fluid    The fluid in the amniotic cavity, or gestational sac, which contains cells derived from the fetus. Sampled with amniocentesis. See also amnion.

amniotic membrane See amnion.

ampulla          The wide outer part of the fallopian tube, lying between the fimbrial end and the narrow isthmus.

ampullary-isthmic junction            The point at which the wide ampulla of the fallopian tube meets the narrow isthmus. The place where fertilization of the egg by a sperm cell normally takes place.

ANA    See antinuclear antibody.

Androcur        See cyproterone acetate.

androgen insensitivity syndrome   Complete or partial resistance to the action of androgens in the body's tissues. Prevents or limits the development of male characteristics in the developing fetus, resulting in intersex. See also testicular feminization.

androgens      Male sex hormones, including testosterone (the main androgen circulating in the blood in men and in women) and androstenedione (which is weaker). Produced in women more or less equally by the adrenal glands and the ovaries (in thecal cells and hilus cells). Produced in much greater quantity in men by the testes (testicles).

androstenedione       A weak androgen, produced in women by thecal cells in the ovary and by the adrenal glands.

aneuploid       See aneuploidy.

aneuploidy     The gain or loss of one or more chromosomes at meiosis, including trisomy (47 chromosomes) and monosomy (45 chromosomes). Caused by chromosomal nondisjunction.

ANF    Antinuclear factor; see antinuclear antibody.

angular pregnancy   When implantation occurs in one or other outer angle of the triangular cavity uterus (that is, out to one side, very close to where the fallopian tubes enter the endometrial cavity). A miscarriage is common. Rupture of the uterus has been reported.

annexin V      A protein molecule with anticoagulant properties bound to chorionic villi, responsible for assisting maternal blood to circulate in the placenta.

anomaly         Distinguishable from an abnormality in that the outcome in the case of an anomaly might not lead to disease or disability. An anomalous kidney, for example, is in the wrong place but does its job perfectly well. The distinction between an anomaly and an abnormality, however, is loose and is not strictly observed.

anorexia nervosa      “Anorexia” means a profound loss of appetite, followed by loss of weight; “nervosa” means that there is a nervous or mental basis for the state, in this case a belief by the person affected, and contrary to the perception of others, that she (very rarely he) is overweight. She stops eating, may induce vomiting, and uses laxatives to keep the intestines empty and the stomach flat. The menstrual periods stop (there is amenorrhea for two reasons: the weight loss and the underlying mental disturbance, both of which cause hypothalamic anovulation. Medical complications from induced vomiting and laxative abuse can be serious, occasionally fatal. Treatment, which includes psychological and psychiatric counseling, is difficult and is not always completely accomplished. It’s a condition chiefly of adolescent girls; the younger the patient the better the chance of cure. For fertility, ovulation induction as often required.

anorexia         See its more traditional name anorexia nervosa, although not all cases nowadays are regarded as primarily “nervous” conditions.

anovulation   Absence of ovulation.

anovulatory cycles    Menstrual cycles caused by ovarian activity (or ovarian cycles) not accompanied by ovulation. The serum progesterone stays low, whereas some development of tertiary follicles and production of estradiol takes place. See also anovulatory dysfunctional uterine bleeding.

anovulatory dysfunctional uterine bleeding         Irregular and generally heavy bleeding caused by anovulatory cycles. The underlying causes and how to prevent the sometimes harmful consequences, including endometrial hyperplasia.

Antagon         The GnRH-antagonist ganirelix made by Organon. Called Orgalutran outside the US.

anteflexed      A forward angle of the fundus of the uterus in relation to the direction of the cervix. Usually only occurs when the uterus is anteverted. Opposite to retroflexed.

anteverted      Refers to the (normal) position of the uterus, meaning that it is tilted forward in relation to the direction of the vagina. Opposite to retroverted. See also transvaginal ultrasound.

antibody         A protein of the immune system capable of binding to an antigen. The binding is specific to the particular antigen and often neutralizes its effects. Antibodies, or immunoglobulins, account for almost half of the proteins circulating in the blood (most of the rest being albumin).

anticardiolipin antibody      (ACA) An antibody that acts against components in the cell membranes (membranes that holds a cell together as well as surrounding some internal cell structures). Looked for in the blood (we ask for a serum anticardiolipin as a possible immune cause of recurrent miscarriages. Intriguingly, the membrane that contains most cardiolipin is the membrane surrounding the mitochondrion (malfunction of which is implicated in causing miscarriage, although how (or if) the antibody might get to the mitochondria is not known. See also lupus anticoagulant and antiphospholipid antibody.

antigen           Anything that stimulates the production of a specific antibody by the immune system.

anti-Müllerian hormone     A hormone produced by the Sertoli cells of the testes in a male embryo to suppress the development of the Müllerian ducts.

antinuclear antibody            (ANA) Antibody made by the body’s immune system that acts against components in the nucleus of the body’s own cells (thus sometimes producing an “autoimmune disease”). Looked for in the blood as a screening test for a possible immune causes of recurrent miscarriages (for which also see anticardiolipin antibody) as well as for the potentially serious autoimmune disease systemic lupus erythematosus (SLE; see also lupus anticoagulant). Synonym: antinuclear factor.

antiphospholipid antibody   An antibody directed at phosphate-containing fatty components of cell membranes, such as cardiolipin (see anticardiolipin antibody). Low levels are probably common and harmless; in higher levels they can cause disease, particularly during pregnancy, including thrombosis and miscarriage.

anti-sperm antibodies          Means the same as sperm antibodies.

antral follicle            A tertiary follicle.

antrum           A fluid-filled space between the follicle cells, the development of which marks the transformation of a tertiary follicle from a secondary follicle. Composes the bulk of the mature, preovulatory follicle (sometimes called the Graafian follicle) and very obvious on transvaginal ultrasound scanning during monitoring of follicular development as dark, “echolucent” spaces within the ovary.

apoptosis        The word for what scientists call programmed cell death, or cellular suicide. This is a normal -- rather altruistic! -- thing for a cell to do, as it purposefully switches on some special genes that then alter its metabolism to dismantle itself and die, for the greater good of the tissue or organ that it's a part of. Pathologists distinguish apoptosis from necrosis. Examples of apoptosis include follicular atresia.

ART    See assisted reproductive technology.

artificial insemination        See assisted insemination.

artificial insemination, husband    See assisted insemination, husband.

aseptic necrosis of the femoral head          Literally, noninfective death of the bone tissue of the top end of the thigh bone (where it forms the hip joint). A rare but serious complication from continued high dosages of cortisone-like drugs, including cortisone, prednisone and prednisolone, sometimes used for treating, for example, sperm antibodies. See also necrosis.

asexual reproduction           The opposite to sexual reproduction. See cloning.

Asherman's syndrome         The combination of intrauterine adhesions and amenorrhea, although see also hypomenorrhea.

aspermia        An absence of semen despite male orgasm; thus, different to azoospermia, an absence of sperm.

assisted conception   A group of medical treatments ranging from assisted insemination (IUI) to in vitro fertilization (IVF), including its technical variants (such as GIFT, ICSI and PGD, and with the following common characteristics: (1) they are aimed at increasing the chance of pregnancy each month, thus overcoming the medical disability of infertility; (2) there is little or no “spillover” of therapeutic effect beyond the cycle or month in which treatment is invoked; and (3) there is some form of procedural intervention, with sperm, eggs or embryos spending some time outside of the body. It’s not necessary for there to be stimulation of the ovaries (superovulation) for multiple development of follicles.

assisted hatching      An in vitro fertilization manipulation in which a small opening is made in the zona pellucida of the early embryo to help the blastocyst emerge prior to implantation. Formerly carried out by judicious use of an enzyme to dissolve the zona (but risking damage to the embryo), leading IVF programs use a microlaser.

assisted insemination          Insemination, or injection of semen or prepared spermatozoa, into the vagina, cervix, uterus (intrauterine insemination) or fallopian tube, to treat infertility. A basic form of assisted conception. The husband’s (or male partner’s) sperm (AIH) or donated sperm (DI) can be used. See also intrauterine insemination.

assisted insemination, husband     (AIH), or assisted insemination in which the semen from the husband or male partner is used.

assisted reproductive technology    (ART) The term is essentially synonymous with assisted conception, but tends to emphasize the technology instead of the medical help to which the technology is put. The effects of unduly separate consideration of the technology is discussed in the box, Brave New Canada?, in WebPage 26.

asthenozoospermia  See oligospermia.

atresia            Process by which a tissue stops growing, loses its function and degenerates. Synonymous with atrophy. See also follicular atresia and apoptosis.

atretic follicle           A tertiary follicle that: (1) is no longer growing; (2) is no longer secreting estradiol; and (3) no longer contains a healthy oocyte, or egg. See also follicular atresia and follicular recruitment.

atrophy           Literally, an absence of nutrition, but in particular the result of such lack in a tissue, which shrinks and loses its normal function. For examples, see endometrial atrophy and follicular atresia. Sometimes the end-result of necrosis.

autonomy       An ethical principle in which value is given to maximizing an individual’s contribution to the making of decisions that affect them. Can be overdone by abrogating professional responsibility through misuse of informed consent.

autosome       A chromosome other than one of the sex chromosomes (which are X or Y). Numbered from 1 to 22, and displayed in a karyotype.

azoospermia  A complete absence of sperm (spermatozoa) in the semen. Detectable only by performing a sperm count, as semen looks the same whether it contains sperm or not. Due either to an obstruction (usually in the epididymis or vas deferens), and called obstructive azoospermia, or to failure of sperm to form or to mature in the testis (called maturation arrest). See also spermatogenesis and testicular sperm extraction (TESE).

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B cells White blood cells or lymphocytes that are part of the immune system and concerned with the production of antibodies. See also T cells and NK cells.

balanced chromosomal translocation        Remember chromosomes occur in pairs in all cells except sperm and eggs. If part of one chromosome is found connected to a completely different chromosome it’s “translocated”. For that person there is no net gain or loss of genetic material, so the translocation is “balanced” and there is no problem. But when that person makes eggs or sperm, some of these will have too much or too little genetic material. The same will be true for an embryo that results. The chromosomal translocation will then be “unbalanced” and the embryo will sooner or later usually result in a miscarriage. If the two particular chromosomes have swapped parts, we call it a balanced reciprocal translocation. See also chromosomal cross-over and chromosomal embryopathy.

basal body temperature chart         An inexpensive way of detecting ovulation through the effect progesterone has on the hypothalamus, increasing the body’s temperature a few tenths of a degree. Best recorded using a BBT thermometer (with a smaller scale than thermometers used to record fevers or high temperatures) first thing in the morning before rising, and preferably in the vagina for accuracy. Day 1 of the chart is the first morning when there is menstruation (a period). Commonly there’s a dip in the temperature just before the sustained rise that indicates that ovulation has occurred (a “biphasic chart”). The chart typically records the days you are menstruating, when you have sex and when you’re aware of mucus and ovulation pain. Best used to document: (1) the presence and length of the luteal phase, especially if clomiphene is being used for ovulation induction; and (2) the timing of symptoms such as premenstrual spotting. Not as good for predicting ovulation as LH-testing in urine.

BBT    See basal body temperature chart.

beneficence   The ethical value that comes from doing good. See also non-maleficence and suffering.

bicornuate uterus     A uterine anomaly in which the Müllerian ducts, before birth, do not join completely, with the consequence that there is a double uterus, in which each of the two sides is smaller than a normal uterus and receives just one fallopian tube. Diagnosed by hysterosalpingogram, by hysteroscopy and laparoscopy, or by transvaginal ultrasound (preferably three-dimensional ultrasound).

biochemical pregnancy        A somewhat insensitive term for when conception and implantation have occurred, producing a positive pregnancy test, but without sign of a gestational sac appearing on transvaginal ultrasound; in other words, a subclinical miscarriage or a menstrual miscarriage.

biopsy Taking a small sample of tissue for diagnosis under the microscope. Biopsies of the endometrium can be done without anesthetic, through the cervix (see premenstrual biopsy). Biopsies of the ovary or of the lining of the peritoneal cavity (e.g. to detect subtle endometriosis) are done at laparoscopy. A testicular biopsy is done to determine why there’s azoospermia. Using microscopic techniques, even an early embryo can be biopsied (see embryo biopsy and preimplantation diagnosis).

blastocyst       Stage of development of the early embryo that has undergone blastulation, in which a fluid-filled cavity forms in the formerly solid ball of cells (the morula), about 5 days after fertilization. For the first time, a distinction can be made between a sheet of cells to one side, which will form the embryo proper, termed the inner cell mass, and the remaining, peripheral cells that constitute the trophectoderm, which -- after the blastocyst “hatches” through the zona pellucida and undergoes implantation -- will form the trophoblast.

blighted ovum           An old-fashioned term for an inevitable miscarriage, meaning that the ovum (in its classical sense for professional embryologists) has not developed normally after fertilization, there being present just the supporting tissues and no embryo. The term is descriptive, it has no diagnostic value as to the cause of the miscarriage.

blood group and antibody screen    Most commonly done before an operation that could cause significant loss of blood, especially if an ectopic pregnancy is suspected, because a blood transfusion might be needed. Also done for investigation of recurrent miscarriages, when the rare but important antibody anti-T_j^A needs to be excluded or detected. Rh-negative women who have a Rh-positive partner who are treated for miscarriage or for ectopic pregnancy often require an injection of Rhogam or anti-D gamma globulin to avoid being sensitized (developing antibodies to) possibly Rh Positive red blood cells from the embryo or fetus.

BMI    See body mass index.

body mass index        (BMI) An estimate of the amount of fat a person has, calculated by dividing his or her weight (expressed in kilograms) by the square of the height (expressed in meters). Normally between about 20 and 25, although the upper limit is higher with age. A BMI below 20 generally causes oligomenorrhea, then amenorrhea, through anovulation. A BMI much over 25 indicates obesity. Sometimes called the Quetelet index, although Quetelet actually devised a different formula (for the interesting background to which see the box, The body mass index, the stars and Monsieur Quetelet, in WebPage 11.

bowel  The intestines. The small intestine (or small bowel) runs from the stomach to the wider large intestine (or large bowel), which starts with the cecum, in the region of the appendix on the right side of the lower abdomen, ascends (ascending colon), turns left (transverse colon), turns downward (descending colon), becomes the sigmoid colon (as it sweeps from side to side a bit), then the rectum, before emerging at the anus.

breakthrough bleeding        Bleeding (usually irregular and light, i.e. “spotting’) while on the birth control pill (the oral contraceptive pill) or while taking a progestogen. With regard to the pill, it is common (and of no sinister importance) in the first few months of pill use; but if it happens after many months’ satisfactory use of the pill then it can signal: (1) interference with the efficacy of the pill (i.e. a risk of ovulation and pregnancy) by an illness with diarrhea, simultaneously taking antibiotics, or a drug interaction (taking additional medications that speed up the pill’s metabolism; or (2) coexisting pathology of the cervix or the uterus. Unexplained or persistent breakthrough bleeding means you should see your physician.

bromocriptine           A drug that mimics dopamine, which is produced by the hypothalamus to normally inhibit production of prolactin by the pituitary gland. Specific treatment for hyperprolactinemia: the tablets are given by mouth unless they cause side effects, in which case the same tablets (but not the capsules) can be used vaginally! Made by Sandoz as Parlodel. The use of bromocriptine for ovulation induction is discussed in WebPage 11.

buserilin        A GnRH-agonist, made by Hoechst as Suprefact. Administered as a nasal spray.

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CA125 antigen          A mucus-like protein produced in some circumstances by surface cells of tissues derived from the Müllerian ducts. Its function is obscure but measurement as serum CA125 antigen can be useful in diagnosing adenomyosis, endometriosis and some cancers of the ovary.

cabergoline    Similar to bromocriptine, but more potent and with fewer side effects; used once or twice weekly to lower production of prolactin in hyperprolactinemia. Not yet approved for infertility treatment, but no adverse fetal effects have been reported when used for ovulation induction.            

caecum           English spelling for cecum (see bowel).

CAH   See congenital adrenal hyperplasia.

canalization  See tubal canalization.

capacitation   An invisible change mature sperm (spermatozoa) undergo to acquire accelerated movement and the ability to undergo the acrosome reaction. Brought about naturally when sperm swim up through the uterus and fallopian tubes, or brought about in the laboratory by spinning and washing the sperm through a series of solutions (in preparation for assisted conception).

carrier            …. of a gene, see alleles.

CAT scan       A special form of x-ray taken with the person enveloped in the x-ray apparatus, which builds up a particularly good image of any cross-section or series of cross-sections through the body, by a process of computed tomography. Particularly useful for investigation of the anatomy of the pituitary gland and hypothalamus when a tumor is suspected or needs to be excluded. More widely available than an MRI scan, which can give even clearer results.

cautery           Short for electrocautery, or diathermy.

CAVD See congenital absence of the vasa deferentia.

CBAVD          Congenital bilateral absence of the vas deferens: see congenital absence of the vasa deferentia.

cecum See bowel.

celiac disease A defect of intestinal absorption caused by abnormal sensitivity to gluten in the diet that can first manifest with recurrent miscarriage or unexplained infertility, despite an absence of diarrhea or other disturbances of bowel function. Diagnosis is suggested by serum antigliadin antibodies and serum tissue transglutaminase (or endomysial) antibodies, but requires biopsy of the lining of the small intestine via gastroscopy for confirmation. Responds to a gluten-free diet.

cervical incompetence          Weakness of the cervix of the uterus revealed during pregnancy, usually because of previous operations on it, but sometimes without prior injury, leading to miscarriage, typically in the second three months of the pregnancy. Diagnosed by examining the cervix during the pregnancy, repeatedly if necessary. Often causes no symptoms until the waters break (the pregnancy membranes from the gestational sac bulge through the opening cervix), when it’s usually too late to treat. Treated before rupture of the membranes with a cervical ligature.

cervical ligature        A stitch or suture placed circumferentially around the cervix to strengthen and support it for the treatment of cervical incompetence.

cervical mucus          Sticky secretion from the canal of the cervix, the job description of which is to keep sperm (spermatozoa) out unless ovulation is about to take place, when it becomes voluminous, watery, stretchable (Spinnbarkheit) and forms a crystalline ferning pattern when allowed to dry on a glass slide. Natural family planning clinics can teach you to look for it in the vagina -- useful for getting pregnant as well as for avoiding it. See also cervicitis, Kremer test, Insler score and postcoital test.

cervical mucus sperm antibodies    Estimation of sperm antibodies in the cervical mucus. The presence of these antibodies can cause negative tests of cervical mucus-sperm interaction, including a negative postcoital test.

cervical polyp            A polyp of the canal of the cervix. A cause of bleeding after sex (postcoital bleeding). Sometimes accompanied by an endometrial polyp, which can cause infertility, and which should thus be looked for with a transvaginal ultrasound.

cervical pregnancy    An ectopic pregnancy located in the wall of the cervix. A particularly dangerous condition because of the risk of uncontrollable bleeding.

cervical score A score (out of 12) for the quality of cervical mucus, gauged by scoring each of the following from 0 to 3: the cervix should be open and the volume of mucus should be good (although every woman will be different for both these parameters, they will be consistent in one woman from ovulation to ovulation); the mucus should be clear, watery and stretchy (Spinnbarkheit); and the mucus should produce a complete “ferning” pattern when it’s allowed to dry on a microscope slide. The first two criteria vary at ovulation in different women (so anything above a score of 9 or 10 can be normal), but the same woman should achieve the same Insler score from one ovulation to the next. Also called the Insler score.

cervical suture          See cervical ligature.

cervicitis        Inflammation of the cervix, usually because of infection. Sperm might or might not have trouble getting through the cervical mucus: this can be tested with a postcoital test. Occasionally cervicitis can mean that there is endometritis and salpingitis, in which case there will usually be pus present in the cervix. A cause of intermenstrual bleeding and postcoital bleeding. Clinically there might be “contact bleeding” when taking a PAP smear.

cervix  The “neck” of the uterus, lying between the body of the uterus (its fundus) and the vagina. See also, cervical mucus, cervical polyp, cervical pregnancy and cervicitis. The embryological development of the cervix and congenital abnormalities.

cetrorelix       A GnRH-antagonist made by Serono. Approved for women undergoing in vitro fertilization), with good results when started on day 7 of the cycle, after 5 or 6 days' Gonal-F in suppressing the LH surge; the dosage, however, appears to be critical, to avoid over-suppressing natural luteinizing hormone. Marketed as Cetrotide.

CGH   See comparative genomic hybridization.

chiasmata      See chromosomal cross-over.

chimerism     The condition when an individual shows two or more genetically different cell lines that are derived from different zygotes, because of intermingling (see microchimerism). Chimerism on a micro scale is more common than generally appreciated, in the sense that most mothers who have had a child will, on careful investigation, be shown to have some white blood cells derived from their fetus or fetuses. See also mosaicism and mixoploidy, although most cases of chimerism do not cause an abnormality of the karyotype.

chlamydia      A germ, or infective agent, responsible for infection of, and damage to, the fallopian tubes. In men particularly, chlamydial infection can cause nonspecific urethritis, with a feeling of burning during the passing of urine or with a yellow-colored discharge from the penis. In women, there can be a vaginal discharge or there can be mild or moderate abdominal pain from acute salpingitis; it should be suspected whenever there is yellow-colored mucus in the cervix during the taking of a PAP smear (i.e. when there is cervicitis). There might be no symptoms in either sex. The diagnosis of a current, untreated infection is made by testing cell scrapings from the canal of the cervix or from the urethra. As a germ, chlamydia is like a virus in some ways (it can grow only inside cells) and like a bacterium in others (it responds to some antibiotics -- especially tetracyclines and erythromycin). When it’s diagnosed, both partners should be treated. A past infection can be revealed by measuring serum chlamydial antibodies, although false positive tests can occur.

chocolate cyst            A cyst of the ovary caused by endometriosis. The name comes from the old, dehydrated and thickened blood that it contains. Often causes an increase in serum CA 125 antigen and can usually be seen on transvaginal ultrasound.

Choragon       hCG made by Ferring.

choriogonadotropin  Generic name for recombinant human chorionic gonadotropin. See Ovidrel.

chorion           The outermost of the two membranes surrounding the gestational sac that encloses the developing embryo. Separate from the amnion until about 14 weeks of pregnancy, after which the two membranes stick together without intervening fluid. Like the placenta, with which at the margins it is joined seamlessly, derived from trophectoderm. See also amnion and chorionic villus.

chorionic gonadotropin        A gonadotropin produced by the trophoblast of the placenta that acts like luteinizing hormone. See human chorionic gonadotropin (hCG).

chorionic membrane            See chorion.

chorionic villi            Plural of chorionic villus.

chorionic villus         A tongue of tissue within the placenta composed of chorion and containing capillaries connected to the blood circulation in the fetus that laps the mother’s blood in the uterus, exchanging oxygen, nutrients and waste products between the fetus’s blood vessels (in the villi) and the mother’s blood. This tissue is sampled for genetic testing with a CVS (or chorionic villus sampling. See also intervillous space. Plural: chorionic villi.

chorionic villus sampling    (CVS) A test done at about 9 weeks pregnancy at which, under the guidance of transvaginal ultrasound, a catheter is passed through the cervix of the pregnant uterus to obtain a small sample of tissue from the placenta (the afterbirth) for genetic testing, such as a karyotype.

chromatid      The name given to the products of a chromosome that has divided during meiosis or mitosis, before separating off as separate daughter chromosomes. See also chromosomal cross-over.

chromosomal cross-over      Remember that the ordinary cells of the body have 46 chromosomes in 23 pairs. The members of each of the pair don’t contain the same genes (this is why you can carry a gene for recessive inheritance without being sick, but if you have both genes there’s trouble). During the cell divisions that produce the germ cells (the process of meiosis), the 46 chromosomes first double to 92 before they end up with the 23 present in an egg or a sperm. Two of the four sibling chromosomes (we call them chromatids) then randomly exchange bits of themselves: there’s a “cross-over’. The points of junction where this happens are called chiasmata. Nature is jumbling up where the genes will end up so that in the long run you don’t always have to inherit two particular genes together just because they live next door to each other on a chromosome. Cross-over does not mean that genes can end up in any chromosome they like: unless “translocated’, they will remain in pairs (of alleles) within a particular pair of chromosomes. See also chromosomal nondisjunction, balanced chromosomal translocation and linkage analysis. Chromosomal crossover is the origin of what geneticists call hybrid vigor.

chromosomal embryopathy When the embryo or fetus is abnormal because of a mistake in its number of chromosomes (see aneuploid and polyploid), with too much or too little genetic material. Usually causes miscarriage. Revealed by performing a karyotype on the products of conception.

chromosomal nondisjunction         Failure of chromatids to separate after chromosomal cross-over during meiosis. The origin of aneuploidy. More common in eggs, or oocytes, than sperm, and increases with age in women.

chromosome  The mixture of a single (but double stranded) long string of genetic material (DNA) wound around supporting proteins. There are 46 chromosomes (23 pairs) in every normal human cell (other than the germ cells). Each cell therefore contains all the genetic information needed to make a human being. But it’s only in the first few days of the embryo that all of a cell’s DNA is accessible: once cells differentiate to have special purposes only the DNA they need remains unmasked. Chromosomes are located in the cell’s nucleus and come in pairs, so that each cell has two alleles of each gene. See also chromosomal cross-over.

chronic           Medically, means slow to develop, and lingering or long-lasting. A chronic inflammation typically consists of fibrous (scar-like) tissue. Opposite to acute.

cilia    Plural of cilium.

cilium Tiny hair-like projections on the surface of some cells, which are thus called “ciliated’. Coordinated beating of the cilia moves mucus and mucus-like substances (such as the cumulus mass) on the surface of ciliated cells in the direction of the cilial beat. An individual cilium has the same basic sub-microscopic structure as the tail (the flagellum) of a sperm cell (a spermatozoon). See also immotile cilia syndrome. Plural: cilia.

cleavage         Process by which a fertilized egg divides repeatedly over several days, forming (for a time) smaller and smaller cells; the process begins at the stage of the zygote and ends with a morula.

Clomid           Brand of clomiphene made by Marion Merrell.

clomiphene    A drug that blocks the action of estrogens and so tricks the pituitary gland into thinking the ovary’s follicles are not producing enough estradiol, so that natural FSH production is temporarily increased, the ovaries thereby are stimulated, and follicles grow. The LH surge and ovulation usually follow naturally, but human chorionic gonadotropin can be given if monitoring is used to make sure the follicle is properly mature. Brand names: Clomid (Marion Merrell) and Serophene (Serono).

cloning           Originally a botanical term meaning asexual reproduction, or reproduction by “budding” rather than by genetic recombination involving an egg and a sperm. Animals can be cloned either by splitting an embryo during cleavage (nature does this in producing monozygotic twinning) or by inserting an adult cell nucleus into a suitably primed secondary oocyte, a process called somatic cell nuclear transfer (and generally still very inefficient, resulting in a new developing embryo in at most a few percent of attempts). See also therapeutic cloning and reproductive cloning.

coagulation system   A complex set of blood and tissue components capable of a cascade of events causing blood to clot. The central event is the conversion of soluble fibrinogen to insoluble, polymerized fibrin through the action of thrombin. In a more moderate way, the coagulation system (and these molecules) lay down the scaffolding for normal development of the placenta, so that abnormalities of blood coagulation may contribute to recurrent miscarriages. See also thrombophilia.

coeliac disease          See celiac disease.

cohort See follicular recruitment.

coitus  Latin for having sex.

colectomy       An operation to remove the colon, performed in children for Hirschsprung’s disease and in young women chiefly for ulcerative colitis and Crohn's disease, and notorious for leaving the fallopian tubes caught up in “repaired” serosa of the pelvic peritoneal cavity, producing a hydrosalpinx on the left side, with resultant sterility, even though the tube on the right side might be normal.                       

collaborative reproduction  Achieving pregnancy with the help of a third party to provide any of: the spermatozoa (see donor insemination); the oocytes (egg donation); or the uterus (surrogacy: see gestational surrogacy and traditional surrogacy). Current issues surround the question of whether or not to inform the child of his or her origins, whether the donor or surrogate should be anonymous or take some part in the child's upbringing, exploitation and autonomy, and (in the case of sperm donation) access to sperm banks by women not in a heterosexual relationship with a sterile man.

colon   See bowel.

compaction    Process by which the separate cells of the early embryo fuse together to form, for the first time, a tissue. Typically occurs at the stage called the morula. With compaction, it becomes difficult to detach a cell for preimplantation genetic diagnosis.

comparative genomic hybridization           (CGH) A molecular DNA diagnostic technique whereby a set of chromosomes (a genome) is compared with a standard set using different colored dyes (typically red and green), so that any areas that do not exactly match will appear green or red instead of brown; a sensitive technique that can be applied to preimplantation genetic diagnosis as well as to chorionic villous sampling, or CVS, and to amniocentesis for prenatal diagnosis, yielding results much faster than is possible with a formal karyotype and more comprehensively than is possible with fluorescent in situ hybridization.

compassion    See empathy for a discussion of its place in the range of feelings one person can have for another.

complement system  A rapidly self-amplifying system of molecules in the body capable, when triggered by the immune system, of killing faulty or foreign cells or bacteria by puncturing their membranes and dissolving their contents.

complete infertility  See sterility.

complete miscarriage           Traditionally, any miscarriage revealed to be complete upon careful inspection of the expelled pregnancy tissue (the “products of conception', meaning that a uterine curettage was not necessary to avoid the risk of retained tissue causing more bleeding or infection. Nowadays we can distinguish a complete from an incomplete miscarriage (and whether or not a curettage should be done) with a transvaginal ultrasound, which can reveal significant retained tissue.

compound heterozygosity    A heterozygous state in which the inherited alleles of the particular gene are different and both harmful, with clinical effects similar to a homozygous state.

conception     The act of becoming pregnant. Traditionally, the fertilization of the egg (the oocyte) by a sperm (the spermatozoon) and the beginning of the growth of the embryo [Butterworths Medical Dictionary]. Since the advent of in vitro fertilization, conception is said to have occurred only if the conceptus has undergone successful implantation, as evidenced by a positive pregnancy test. See also conception rate and pregnancy.

conception rate         The percentage of months or treatment cycles that result in conception, including biochemical pregnancies, ectopic pregnancies, miscarriages and all potentially viable pregnancies (twins are not counted twice); less important for most purposes than the implantation rate, pregnancy rate, viable pregnancy rate and the take-home-baby rate.

conceptus       The product of conception from fertilization.

congenital abnormality       Abnormal development of a body part during the life of the embryo or fetus, usually but not always apparent at or soon after birth. It can be genetically inherited or be acquired by exposure to a physical or chemical insult, such as the action of a teratogen (a drug or other substance in the environment), during development in the mother's uterus. Few congenital abnormalities can be associated with a specific cause, and an apparent cause might not be the true one.

congenital      An adjective meaning that something, especially an abnormality or anomaly, is present from birth. The cause for such a condition can be hereditary (genetic) or it can be an environmental factor operating before birth. See also congenital abnormality.

congenital absence of the vasa deferentia Congenital (present from birth) absence of the two vasa deferentia, which conduct sperm from the testes to the ejaculate; hence a cause of obstructive azoospermia. Because the vas deferens is usually affected on both sides, the word “bilateral” is often inserted, as CBAVD. Infertility is inevitable, but can be overcome using in vitro fertilization with testicular sperm extraction (but see the cautionary box, From father to son, in WebPage 10. The cause, however, is usually the presence among the man's genes of one of the serious alleles for the genetic disease cystic fibrosis (which, having recessive inheritance, results when there are two such alleles present); it can also come about when there are one or two of the less serious abnormal alleles for this condition. The more common of the abnormal alleles should therefore be screened for (using a specially set up polymerase chain reaction on white blood cells): should an abnormal allele be present (delta F508 is the most common seriously abnormal one), the woman should be screened too, to predict the chance of cystic fibrosis occurring in the offspring.

congenital adrenal hyperplasia      (CAH) Enlargement and abnormal function of the adrenal glands, usually from before birth, owing to a genetically determined, partial block in the production of cortisol, the adrenal glands’ main hormone, resulting in overproduction of subsidiary hormones, including androgens, tending to virilize the female fetus, which can present at birth with intersex. In mild forms does not manifest until puberty, when the symptoms of oligomenorrhea and hirsutism mimic those of polycystic ovary syndrome. See also serum 17-hydroxyprogesterone.

congenital anomaly  See congenital abnormality.

congenital bilateral absence of the vasa deferentia         (CBAVD) See congenital absence of the vasa deferentia.

control group When a research study is done (an “experiment', maybe), the procedure, drug or process being tested or examined on the treatment group needs to be compared with a similar group that doesn't receive the treatment; we call this group the control group. The groups can consist of people, embryos, research animals, for example.

cornual pregnancy    A commonly used term for an interstitial pregnancy, but can also refer to an angular pregnancy, a pregnancy in a unicornuate uterus or a pregnancy in one side of a bicornuate uterus.

corpus luteum defect            See luteal phase defect.

corpus luteum           Latin for yellow body, the description being that of the solid or cystic structure in the ovary after ovulation. Derived from the ovulating Graafian follicle. At first red and friable as arteries and veins invade the collapsed follicle, it soon matures into a gland that is very efficient at producing progesterone, a hormone that's soluble in the fat and which therefore gives the corpus luteum its yellow color. Provides its name to the second, or luteal phase of the ovarian cycle, as well as to luteinizing hormone, which causes the corpus luteum to be formed and sustains it until, in the event of pregnancy, it is supported instead by human chorionic gonadotropin. The appearance of the corpus luteum on transvaginal ultrasound is so variable (and so able to be confused with a serious abnormality of the ovary) that for accurate diagnosis of
such pathology it is best to scan in the follicular phase or while taking a progestogen to prevent formation of this structure. Plural: corpora lutea.

Crinone         A vaginal gel that contains 8%progesterone. Well absorbed and with a potent local effect on the endometrium. Used to mimic (or supplement) the ovarian luteal phase. A weaker (4%) formulation is available for longterm use in patients with polycystic ovary syndrome or after the menopause to prevent endometrial hyperplasia.

crossover        See chromosomal cross-over.

cryostorage    Storage (at the very low temperature of liquid nitrogen) of sperm, embryos or (very recently, but still controversially) unfertilized eggs, after special preparation of these cells during cooling to replace much of the water they contain with a cryoprotective substance such as dimethylsulfoxide, propanediol or glycerol. Storage is biologically safe for a decade or more, but the existence of banks (especially of embryos) has been a concern of some in society.

cryptomenorrhea      Literally, “hidden menstruation”. Apparent amenorrhea caused by an obstruction to the outflow of periodic bleeding from the uterus. Causes include an obstruction in the vagina. Typically there is periodic pain coinciding with the timing of the hidden menstrual flow. The causes of cryptomenorrhea include an imperforate hymen.

cryptorchidism          Literally (from the Greek), “hidden testicle”. A condition in which there is incomplete descent of the testis or testes from the abdomen into the scrotum. Synonymous with undescended testis. See also orchidopexy.

CT scan          See CAT scan.

culture medium        The fluid in which cells or tissues, including eggs, sperm and embryos, are grown. It consists of water, salts and nutrients. Different media have turned out best for different purposes. In the early days of in vitro fertilization, several different media seemed to produce equal results: examples included Ham's F10, Whittingham's T6. Quinn's medium (said to be based on human tubal fluid, though in reality different to the fluid in the fallopian tube) produced better results than the first generation media. Today's third generation media, or stage specific media, give superior results and are used increasingly. Plural: culture media.

cumulative chance of pregnancy    The accumulating chance, month after month, of successfully having gotten pregnant. With a monthly fertility (a monthly chance of pregnancy, or fecundability) of, say, 20 percent, there's a 20% chance of pregnancy by the end of the first month, a 20% of 80% (= 16%) chance of pregnancy in the second month, and so a cumulative 36% (20%+16%) chance by the end of the second month. Further accumulation lies behind the construction of a life-table, as developed in Appendix 1.

cumulus mass           A collection of specialized granulosa cells, surrounding the ovulating egg (or secondary oocyte) in a sticky, mucus-like matrix. Sticks to the fallopian tube's fimbrial end after ovulation by a specific interaction with the tube's cilia.

curettage        The operation of scraping out the contents of a hollow cavity (such as the endometrial cavity of the uterus) with a curette, for making a diagnosis or for therapeutically removing abnormal tissue. A D and C is abbreviated jargon for dilatation of the cervix and curettage of the uterus). When a curettage is done to empty the uterus of normal or abnormal pregnancy tissue, a special suction apparatus is used and we refer to the operation as a vacuum curettage.

curette            Spoon-shaped instrument for carrying out curettage.

CVS    See chorionic villus sampling.

cyproterone acetate  A progestogen that is particularly effective at blocking the effect of male sex hormones (androgens)on the skin, and therefore reducing abnormal hair growth (hirsutism) and acne. Found singly in Androcur and in combination with an estrogen in Diane-35, a formulation used for oral contraception. Dangerous if taken in pregnancy, because it stops male fetuses from developing normal genital organs. Not available in the US.

cystic fibrosis A serious genetic disease (with a recessive inheritance pattern) characterized by a major disturbance of the body's mucus secretions, and thus a cause of incapacitating disease of the lungs. Important in our context because the heterozygous (or carrier) state in men can manifest with azoospermia due to congenital absence of the vasa deferentia -- the infertility of which is nowadays able to be overcome with testicular sperm extraction and ICSI, thus risking inadvertent transmission. See also delta F508, and the box, From father to son, in WebPage 10.

cytokines       Soluble signalling molecules produced by cells to activate the immune system.

cytoplasm       The part of a cell that is not the nucleus (the nucleus contains the chromosomes). The cytoplasm is contained by the cell's plasma membrane and contains all the other cellular structures, including the mitochondria. Genetic inheritance is mostly by way of the nucleus (with a contribution from mother and father); a small part is by way of the cytoplasm (with a contribution only from the mother). It is the cytoplasm of the egg (as a secondary oocyte) into which a sperm cell (spermatozoon) is injected in the process of intracytoplasmic sperm insertion. See also mtDNA.

cytotrophoblast         Cells in the developing placenta that are derived from the early embryo's outer layer (the trophectoderm of the blastocyst) and then persist through pregnancy, producing either syncytiotrophoblast or extravillous trophoblast.