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galactorrhea Demonstrable milk production from the breasts other than while purposefully breast-feeding; caused by hyperprolactinemia or, sometimes, by disease in the breast or wall of the chest.

gamete A general term for a germ cell that has been released or separated from its gonad, i.e. an egg or a sperm. See also haploid.

gamete intrafallopian transfer An assisted conception procedure in which unfertilized eggs plus sperm (i.e. gametes) are transferred to the fallopian tube, so that fertilization occurs in the normal place. Because in vitro fertilization is avoided, for some people GIFT is more morally acceptable than IVF is. The disadvantages are that laparoscopy is required and that for the pregnancy rate to be comparable to IVF too many eggs need to be transferred, risking high multiple pregnancy. See also zygote intrafallopian transfer (ZIFT).

ganirelix A GnRH-antagonist made by Organon. The first to be FDA approved for women undergoing in vitro fertilization), with good results when started on day 7 of the cycle, after 5 or 6 days FSH in suppressing the LH surge; the dosage, however, appears to be critical, to avoid over-suppressing natural luteinizing hormone. Marketed as Antagon in the US and as Orgalutran elsewhere.

Gärtner’s duct See mesonephric duct.

gastrulation A step of major reorganization of the developing embryo, coinciding time-wise with the missing of the menstrual period in the early pregnant woman, in which the third, or “middle” layer (the mesoderm) forms. Occurs after blastulation (the transformation giving rise to the blastocyst) and before neurulation (the transformation forming the brain and spinal cord).

gender Often a genteel term for distinguishing the male from the female sex. More precisely, the cultural attributes that attach to biological sex. In principle may be masculine (when more often than not it attaches to the male sex), feminine (more often than not with the female sex) or neuter (the “gender” non-sexual or inanimate objects have). Gender identity is not to be confused with heterosexual (opposite sex) or homosexual (same sex) preference. See also intersex and transsexualism.

gene The smallest unit of inheritance coded by DNA. Generally, a single gene codes for a single protein. Genes come in pairs of alleles (one inherited from each parent) in all tissues except the haploid cells, particularly the spermatozoon.

genes See gene.

genetic-plus-gestational surrogacy See traditional surrogacy.

genome A full set of DNA code (a full set of genes) for a whole animal or organism, or for a defined component of an organism, such as a mitochondrion.

germ cell Distinct from the somatic cells that compose most of the body’s tissues and organs, germ cells form the eggs and sperm that will form the nextgeneration. Early germ cells are diploid and replicate by mitosis, but during their development they enter meiosis (for eggs this occurs before birth, for sperm it occurs after puberty), so that at the time of fertilization the contributing sperm and egg are haploid. So also yolk sac, oogonium, spermatogonium, primary oocyte, secondary oocyte, spermatid.
gestation See pregnancy.

gestational sac A fluid-filled bag of membranes in which the embryo forms during pregnancy. Visible on transvaginal ultrasound from about 5 weeks from the last menstrual period. Technically, the amniotic cavity (and later in pregnancy able to be sampled with amniocentesis).

gestational surrogacy A form of collaborative reproduction in which the woman who is the surrogate for the intended pregnancy receives embryos from the commissioning infertile couple, who have undergone in vitro fertilization, then, by becoming pregnant, carries (or “gestates’) the pregnancy, gives birth, and then gives up the baby to the baby’s genetic parents. In principle the practice can be done for altruistic or commercial reasons. Its pitfalls and perils are described in WebPage 23.

gestrinone Generic name for Dimetriose, a drug used in the treatment of endometriosis that inhibits ovulation and blocks the action of both estrogen and progesterone; risks and side effects are similar to danazol; it is usually taken just twice weekly, by mouth.

GIFT See gamete intrafallopian transfer.

glucose tolerance test See plasma glucose.

GnRH See gonadotropin releasing hormone.

GnRH-agonist A GnRH-analog that briefly stimulates the pituitary gland to release follicle stimulating hormone (FSH) and luteinizing hormone (LH), but then within a few days reduces these hormones to low levels (you could say that the pituitary has had a clamp put on it), stopping these hormones from competing with administered hormones -- and, particularly in women, suppressing the LH surge that otherwise can spoil the timing of egg retrieval in an assisted conception program such as IVF or GIFT. Examples include: leuprorelin(Lucrin, made by Abbott, used in Australia and Europe) or leuprolide (Lupron, made by Abbott in the US); nafarelin (Synarel, by Syntex); goserelin (Zoladex, by ICI); triptorelin (Decapeptyl, by Ipsen Biotech and used in Europe) and buserelin (Suprefact, by Hoechst, used in Europe).

GnRH-analog Synthetic hormones related to the natural hormone GnRH, or gonadotropin releasing hormone. See GnRH-agonist and GnRH-antagonist.

GnRH-antagonist A GnRH-analog that (unlike GnRH-agonists) immediately stops the pituitary gland from releasing the gonadotropins follicle stimulating hormone (FSH) and luteinizing hormone (LH). Can substitute for GnRH-agonists for many gynecological purposes (particularly to suppress the LH-surge in assisted conception), although its use with pure FSH preparations (such as Fertinex, Gonal-F, Metrodin HP or Puregon) can lead to poor egg quality unless the dosage is carefully controlled or some luteinizing hormone is added to the stimulation regimen. See cetrorelix and ganirelix.

gonad A gender-neutral word for an organ that contains germ cells and produces gametes, namely the ovary and the testis.

gonadotrophin English spelling for gonadotropin. The etymological derivation of the spellings is different, though. A trophic effect of a hormone implies a nourishing action, whereas a tropic effect of a hormone implies a switching action; arguably it’s the latter (American) usage that is now known to be the more physiologically correct.

gonadotropin releasing hormone (GnRH). A hormone produced by the hypothalamus of the brain to regulate production and release of the gonadotropins follicle stimulating hormone and luteinizing hormone. Can be administered to induce ovulation when it is deficient (particularly in amenorrhea due to weight loss or excessive exercise), but it has to be given in small amounts directly into a vein, every 60 to 90 minutes for the two weeks of a normal follicular phase (with an electronic syringe-driver), mimicking its natural pattern of secretion (see WebPage 11 for details). See also GnRH-analog.

gonadotropin Any hormone that switches on the function of the gonads. There are two main families of gonadotropins: (a) the gonadotropin that stimulates the growth of the follicle, or follicle stimulating hormone (FSH); and (b) those that cause ovulation from the mature follicle and stimulate the corpus luteum that results to develop and to produce progesterone, namely luteinizing hormone (LH) and human chorionic gonadotropin (hCG). FSH will cause growing follicles to produce the estrogen estradiol, provided that a small amount of LH (or hCG) is present. FSH and LH are produced in the pituitary gland, whereas hCG comes from the placenta in pregnancy. In men, FSH stimulates the Sertoli cells of the testicular tubules, and hence drives spermatogenesis; LH and hCG stimulate the Leydig cells to produce testosterone.

Gonal-F Recombinant follicle stimulating hormone made by Serono. Generically known as follitropin alpha.

good responder High responder: discussed under low responder.

Goretex Not just the stuff of ski clothing: used in a special surgical specification as a barrier to the formation of peritoneal adhesions.

Goserelin A GnRH-agonist, made by ICI as Zoladex. Administered by monthly injection.

Graafian follicle Synonym for preovulatory follicle. A large, mature tertiary follicle that will respond to an adequate LH surge or injection of human chorionic gonadotropin (hCG) by undergoing ovulation, releasing its egg. Produces estradiol and, with exposure to LH or hCG, progesterone. Named after Reijnier de Graaf (1641-1673), the first person to see and to appreciate the importance of the ovarian follicle.

granulosa cells Ovarian follicle cells from a tertiary follicle.

growth hormone One of the six main hormones that come from the front, glandular part of the pituitary gland, the adenohypophysis. A small amount is needed in the adults for follicle stimulating hormone to work properly. This led some doctors to add it injections of FSH in poor responders, but subsequent research has shown that increasing the amount of FSH does the same thing (and FSH is cheaper to buy than growth hormone).

 

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habitual abortion A rather insensitive way of referring to recurrent miscarriages.

haploid The state of a cell with 23 chromosomes (half the normal diploid chromosome state), found normally only in the spermatozoon and the egg (as the secondary oocyte). See also meiosis and gene. The noun form of this adjective is haploidy (the state of being haploid).

hatching blastocyst See blastocyst.

hazard An event, usually unwanted, sometimes in the sense of a penalty. Unlike risk, which has a number attached to it (it’s quantitative), a hazard is “yes” or “no”: it’s either realized, or experienced, or it’s not; although one hazard can be worse to experience than another, you can’t put a figure on it (it’s said to be qualitative). For more on the difference, read the box, Risks and hazards0.

hCG See human chorionic gonadotropin.

heparin A naturally occurring “anticoagulant”, or substance that stops blood from clotting. Used in medicine generally to prevent or to treat thrombosis, and sometimes in pregnancy to reduce the risk of miscarriage in someone who has had recurrent miscarriages by improving blood flow in the placenta. Administered by injection under the skin.

hermaphrodism See intersex.

heterotopic pregnancy The coexistence of a pregnancy in the uterus with an ectopic pregnancy.

heterozygous An adjective to describe the genetic state when the pair of genes under consideration consists of two alleles that are different. Disease or disability can follow if one of the alleles is at once seriously abnormal and dominant (see dominant inheritance) over the other allele, or if the alleles are different but both are deleterious (a state called compound heterozygosity). See also homozygous.

high multiple pregnancy An order of multiple pregnancy higher than twins.

high responder See the description for low responder.

hirsutes See hirsutism.

hirsutism Hair (particularly, “terminal hair -- hair that is thick and pigmented) on the face, chest (between the breasts or around the nipples), abdomen or thighs that is getting worse, or is worse than other family members, or is worse than usual for one’s race. More likely to be important medically if the periods are disturbed (i.e. if there is oligomenorrhea or amenorrhea). See also polycystic ovary syndrome.

HIV Human immune-deficiency virus, the virus that causes acquired immune deficiency syndrome, or AIDS. Type 1 and type 2 viruses are recognized, and both are usually tested for in serum HIV antibodies.

HLA molecules Human leukocyte antigens, also known as tissue typing molecules, responsible for acceptance or rejection of tissue grafts, and implicated in the survival or rejection of the fetus in pregnancy.

hMG See human menopausal gonadotropin.

homozygous An adjective to describe the genetic state when the pair of genes under consideration consists of two alleles that are the same. Disease or disability can follow if both alleles are seriously abnormal -- a condition known as recessive inheritance (and a good example of which is cystic fibrosis). See also heterozygous.

hormone replacement therapy (HRT) This could literally be the replacement of any naturally deficient hormone, but in practice it means estrogen replacement therapy.

hormone A chemical substance, natural or not, which acts as a signal from one part of the body to another, via the bloodstream. The study of hormones is the science of endocrinology, and the hormone systems of the body are collectively known as the endocrine system.

hPG See human pituitary gonadotropin.

hrFSH Human recombinant follicle stimulating hormone.

HRT Hormone replacement therapy; see estrogen replacement therapy.

HSG See hysterosalpingogram.

HTF So-called Human Tubal Fluid.

Huhner’s test See postcoital test.

human chorionic gonadotropin (hCG) A gonadotropin produced by the placenta in pregnancy (specifically it’s produced by the trophoblast of the chorionic villi); the hormone measured in performing a pregnancy test. The generic (‘no frills’) name for Pregnyl and Profasi, which are preparations of hCG obtained by extracting it from the urine of pregnant women, and Ovidrel, which is made by recombinant gene technology. Mimics the action of luteinizing hormone (LH), but has a very much longer duration of action -- and this gives hCG considerable advantages over LH in clinical use. Given as an injection to lead to ovulation from a mature follicle 38 hours after the injection; or to stimulate ongoing function of the corpus luteum, particularly its production of progesterone. So it is typically given after a course of follicle stimulating hormone (FSH) in assisted conception (IVF or GIFT) programs and ovulation induction programs 36 hours before the expected time of egg retrieval (or before having sex or IUI), and then sometimes in further, smaller doses to support the luteal phase that follows. Sometimes used with clomiphene. Ovarian monitoring is needed for its correct use with FSH or with clomiphene. hCG treatment can precipitate the ovarian hyperstimulation syndrome (OHSS). The proper clinical use of hCG is described in WebPage 11.

human menopausal gonadotropin (hMG) A mixture of follicle stimulating hormone (FSH) and luteinizing hormone (LH) extracted for therapeutic use from the urine of menopausal women (women after the menopause normally produce these hormones in high concentration). Marketed as Humegon (Organon) and Pergonal (Serono). Metrodin (Serono) is hMG from which LH has been removed, and Metrodin HP (Serono) is Metrodin from which other urinary proteins have been removed too, resulting in very pure FSH. Ferring market a highly purified hMG containing both FSH and LH, but not in Australia (see Menogon or Repronex). No cases of transmitted (infectious) disease have been recorded after the use of hMG preparations, unlike human pituitary gonadotropin. See also recombinant FSH and recombinant LH.

human pituitary gonadotropin (hPG) A mixture of follicle stimulating hormone (FSH) and luteinizing hormone (LH) extracted directly from pituitary glands obtained at autopsies; not used in Australia or elsewhere since 1986, when it was shown that Creutzfeldt-Jakob disease (CJD), a deadly form of dementia, had been transmitted from its use, presumably due to contaminating and infected brain tissue. Before 1986 it had been used mostly for ovulation induction in women with amenorrhea (absent periods) for which other hormones or drugs had not been effective, although sporadic instances of its use for in vitro fertilization are known in Australia. No new cases of CJD have been reported among former users of hPG since the early 1990s.

human research ethics committee See institutional ethics committee and institutional review board.

Human Tubal Fluid Embryo culture medium formulated to resemble the constituents found within the fallopian tube by Dr Patrick Quinn, an Australian scientist living in Los Angeles, but differing in a number of respects.

Humegon Mixture of human menopausal gonadotropins containing follicle stimulating hormone made by Organon; virtually equivalent to Pergonal.

hybrid vigor See chromosomal cross-over.

hydatidiform mole An abnormal conceptus in which the chorionic villi of the placenta have become cystic and swollen, typically because the chorion has not developed in connection with a fetus that has a properly functioning circulation. The placenta looks like a bunch of grapes. See also hydatidiform mole, complete and hydatidiform mole, partial.

hydatidiform mole, complete A hydatidiform mole in which there is no embryo or fetus. The size of the uterus is often larger than expected from the date of the last menstrual period, often with a high level of serum hCG; there may be bleeding; and there is a classic abnormal appearance on transvaginal ultrasound. Caused by pregnancy following abnormal fertilization in which the oocyte is “empty”, that is it loses its pronucleus, and either (1) the male pronucleus from a single fertilizing sperm doubles (the karyotype of the mole is then always 46,XX, because 46,YY is immediately lethal) or (2) there are two male pronuclei from two fertilizing sperm (in which case the karyotype is either 46,XX or 46,XY). Treatment is by vacuum curettage, but there is a persisting danger of cancer (choriocarcinoma) and specialist medical follow-up is essential.

hydatidiform mole, partial Abnormal conceptus in which there is coexistence of a hydatidiform mole with a fetus; caused by triploidy. Not as dangerous as a molar pregnancy without a fetus (see hydatidiform mole, complete), but medical follow-up is still necessary.

hydrosalpinx Blockage of the outer, or fimbrial end of the fallopian tube, usually as a result of chronic salpingitis (but also sometimes from peritubal adhesions, from a salpingotomy or partial salpingectomy for a tubal pregnancy, or from fimbriectomy), resulting in its distension by watery contents. An untreated hydrosalpinx (even if only one tube is affected and the other tube is normal) can cause infertility and failure to conceive even with in vitro fertilization (explained in the box, Hydrosalpinx: reintroducing a villain, in WebPage 20.

hyperplasia Pathologists use this word to mean an abnormal increase in the number of cells seen in a sample of tissue. See also endometrial hyperplasia.

hyperprolactinemia An increase in serum prolactin; can be accompanied by galactorrhea and amenorrhea; causes are described in WebPage 11.

hypomenorrhea Light periods, particularly in a woman who has previously had much heavier periods. Occurs normally on the oral contraceptive (birth control) pill. Occurs abnormally with intrauterine adhesions or endometrial atrophy; see also Asherman's syndrome.

hypospadias A congenital abnormality in males in which the urethra does not reach the tip of the penis, but opens near its base. The penis is usually short and curved, which can make sex difficult and can contribute to infertility.

hypothalamic anovulation Absence of ovulation caused by insufficient GnRH drive from the hypothalamus, so that the pituitary gland doesn’t produce enough follicle stimulating hormone. Usually accompanied by absent periods (amenorrhea). Causes are described in WebPage 11.

hypothalamic chronic anovulation See hypothalamic anovulation.

hypothalamus Part of the brain lying immediately above (and connected to) the pituitary gland; responsible for producing gonadotropin releasing hormone and dopamine, among other hormones and substances (including the endorphins, serotonin, etc.). In women (when conditioned to cyclical function by a lack of exposure to male sex hormones before birth) it resonates with the ovarian cycle and cooperates with the pituitary gland to cause corresponding cyclical production of follicle stimulating hormone and, particularly, a timely LH surge. Responds to progesterone by raising the body’s temperature (see basal body temperature chart).

hysterectomy A surgical operation at which the uterus is removed, usually including the cervix (hence a “total hysterectomy’), but not necessarily including the fallopian tubes and ovaries.

hysterosalpingogram (HSG) An x-ray of the endometrial cavity and the inside (the lumen) of the fallopian tubes, thus outlining them. Performed by injecting a fluid medium that blocks x-rays through the cervix, so that it first fills the endometrial cavity and then flows out along the tubes, finally casting shadows between the loops of intestine if the tubes are open (illustrated in WebPage 5). The test is uncomfortable or painful to have done, because of contractions of the uterus, which can be partially overcome by taking one of the same drugs that are used to overcome dysmenorrhea, namely the NSAIDs (I suggest taking 2 tablets or capsules 30 minutes before the test). See also selective salpingogram.

hysteroscopy An examination of the endometrial cavity of the uterus by a thin fiberoptic instrument, similar to the instrument used for laparoscopy. Hysteroscopy can be done in the office, with or without sedation, to make a diagnosis, or in the operating room under general anesthesia, often in association with laparoscopy or to carry out a hysteroscopic operation, such as removal of an endometrial polyp, submucous fibroid or uterine septum; see also endometrial resection.

 

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ICSI See intracytoplasmic sperm insertion.

IEC Institutional ethics committee (see ethics committee).

IL-10 See interleukin 10.

IMB See intermenstrual bleeding.

IMC Abbreviation for inevitable miscarriage, or for an imminent or incomplete miscarriage.

imminent miscarriage An alternative term for inevitable miscarriage.

immotile cilia syndrome A disease syndrome caused by abnormal sub-microscopic structure of cilia, which therefore do not function properly during embryonic life, childhood and adulthood. The consequences are situs inversus, in which the developing internal organs in the embryo rotate randomly (so that 50% of affected people have their heart on the right side of the chest and their liver on the left side of the abdomen), abnormal sinuses, a bad form of chronic bronchitis called bronchiectasis, because mucus is not cleared from lungs properly, and male infertility because the sperm tail (the flagellum) has the same sub-microscopic structure as the cilia and cannot propel the spermatozoon. Curiously, female fertility is often normal or adequate: it seems the cilia of the fallopian tube’s fimbrial end still make useful contact with the cumulus mass at ovulation, stopping the egg from getting lost and giving the muscular contractions of the tube the chance to carry the egg down to the ampullary-isthmic junction. Also called Kartagener's syndrome, after the Swiss physician Manes Kartagener, who first described a triad of situs inversus, abnormal sinuses and bronchiectasis.

immune system The body system devoted to resisting parasitic organisms (including viruses, bacteria, fungi and parasitic animals) and to identifying altered body cells (such as cancer) and destroying them. Includes nonspecific mechanisms (“innate immunity”) as well as, particularly, the lymphoid system vertebrates have evolved to recognize antigens and, in response, to produce specific, neutralizing antibodies. Excessive activity can lead to the immune system turning on normal tissues, or autoimmunity.

immunobead tests Tests that look for human antibodies attached to cells, especially (in our context) antibodies attached to sperm cells (see sperm antibodies). The test involves tiny plastic beads coated with antibodies to human antibodies: if they are seen to attach to sperm cells then the presence of antisperm antibodies on the sperm cells is inferred.

imperforate hymen See cryptomenorrhea.

implantation The process by which the embryo’s trophoblast attaches to the mother’s endometrium and penetrates it, establishing contact between the trophoblast’s developing chorionic villi and the maternal blood. See also blastocyst. Signifies the commencement of gestation or pregnancy.

implantation bleeding A small to moderate amount of vaginal bleeding at the time that implantation becomes established. The physiology behind it is described in WebPage 3. Implantation bleeding can be confused with a menstrual period (particularly the last menstrual period) to give a false impression that pregnancy has not happened or, later, a false estimate of the duration of the pregnancy.

implantation rate The proportion of transferred embryos in an in vitro fertilization procedure that produce a gestational sac visible on transvaginal ultrasound. Unlike for the conception rate and the pregnancy rate, twins (with separate sacs) are counted separately. An important index of a clinic's success rate with IVF because it reflects embryo quality independently of the number of embryos transferred.

impotence Inability to sustain an erection of the penis and hence to ejaculate. Occasional impotence is of no special psychological or medical importance. Although persistent impotence is most often due to psychological causes, medical tests are important.

in vitro Latin for “in glass’, meaning “in the laboratory’. (In actual fact, these days, it's usually “in plastic'!) See also in vitro fertilization.

in vitro fertilization IVF, or fertilization of the egg (the secondary oocyte) by a sperm (a spermatozoon) in vitro, i.e. in the laboratory. Necessary if the fallopian tubes are diseased or missing; useful if sperm fertilizing capacity is doubtful, because evidence of fertilization can be seen before the egg is transferred as an embryo.

in vitro maturation Maturation in the laboratory of the egg (as a primary oocyte) obtained from an immature tertiary follicle until it becomes a secondary oocyte competent to be fertilized by sperm using in vitro fertilization. The smaller the follicle, the lower the proportion of eggs that mature successfully. ICSI can be used to increase the proportion of eggs that will fertilize, but the embryos on average do no better, and so no advantage is conferred by ICSI in this situation.

in vitro penetration test One of several tests of the ability of sperm to penetrate cervical mucus at the time of ovulation or under the influence of estrogen. See Kremer test, postcoital test.

incomplete miscarriage (IMC) Any miscarriage before all miscarriage tissue has been expelled. Traditionally a uterine curettage was done after a miscarriage, in the belief (often accurate) that there would still be some immature pregnancy tissue left in the uterus that could cause more bleeding and get infected. Nowadays we can distinguish an incomplete from a complete miscarriage (and whether or not a curettage should be done) with a transvaginal ultrasound, which is able to reveal significant retained tissue. Management is similar to the management of an inevitable miscarriage (and both are abbreviated IMC).

induced abortion See abortion.

inevitable miscarriage (IMC) Traditionally any bleeding from the vagina during early pregnancy with, on vaginal examination, opening of the cervix. Today, the diagnosis can be made much sooner (and distinguished from a threatened miscarriage) by not detecting a normal embryo in a gestational sac on transvaginal ultrasound. Management is similar to the management of an incomplete miscarriage, often requiring curettage (and both are abbreviated IMC).

infertility Not getting pregnant as quickly as expected. See also: sterility; subfertility or relative infertility; and suffering.

informed consent An administrative and legal device by which approval to proceed based on known or predicted consequences is obtained and recorded from a patient or from a volunteer for medical research, and thus avoiding an accusation for what otherwise might be an assault. Just what “informed” means can be the subject of much legal and ethical wrangling. One modern interpretation is that it means as much as the person giving the consent demonstrates that he or she wants to know (although most physicians, ethics committees, institutional review boards and courts underpin this with a minimum everyone should be told about the procedure being consented to). Discussed in WebPage 26, especially the box, Autonomy and respect for persons.

inhibin A protein hormone produced in women by developing follicles as well as by the corpus luteum, and in men by the testis in the presence of spermatogenesis, and acting on the pituitary gland to inhibit the production of follicle stimulating hormone. In women, falling levels occur as the number of developing follicles reduces to low numbers leading up to menopause, thus causing the elevation of serum FSH and shortening of the follicular phase that characterizes the premenopause. In men, appreciable levels of serum inhibin B, a subclass of the inhibin family, predicts the presence of at least a small amount of sperm production.

inner cell mass Group of cells that differentiates within (but to one side of) the developing embryo when it is a blastocyst and which will, if all goes well after implantation, form the embryo-proper, or fetus. Cells from the inner cell mass can be used to produce embryonic stem cells. See also trophectoderm.

Insler score See cervical score and monitoring.

Institutional Ethics Committee (IEC) See ethics committee.

Institutional Review Board (IRB) The US equivalent of an institutional ethics committee, set up to govern the ethical conduct of medical research.

integrins Proteins present on the surface of cells that are needed for cells stick to each other with the help of adhesion molecules. Important in implantation and in the proper construction of the placenta, so that abnormalities or mutations can result in infertility or recurrent miscarriage.

integrity A systematic ethical goal that preserves the values of truth, accountability, equity and consistency.

Interceed Used for minimizing adhesions in the peritoneal cavity after a surgical operation involving the fallopian tubes or ovaries. The material is woven from fibers of modified cellulose and, after being placed over abdominal surfaces the serosa of which is likely to have been damaged, dissolves in about a week or two into simple sugar molecules (which are then absorbed by the body and metabolized); in the meantime, the cloth keeps the covered surfaces apart while the serosa reforms. Controlled trials have shown Interceed to be effective in preventing or reducing adhesions, but an adhesion-free result is not guaranteed. In my experience Interceed is exceptionally useful when dense adhesions resulting from previous operations are being treated. Made by Johnson and Johnson. The principles and practice of prevention of pelvic adhesions is described in the box, Adhesions or healing, in WebPage 13.

interleukin 10 A signalling molecule that inhibits the immune system, so preventing rejection of the fetus during pregnancy. It is thought that insufficient interleukin 10 is a cause of miscarriage.

intermediate trophoblast See extravillous trophoblast.

intermenstrual bleeding (IMB) Bleeding between periods that are otherwise regular. If it happens while on the oral contraceptive pill it’s called breakthrough bleeding; if it happens over a few days before a period starts properly it’s premenstrual spotting; if it happens after sex it’s postcoital bleeding. These forms of IMB have different, usually important, causes. The formal term for it is metrorrhagia.

intersex A state of ambiguity regarding the assigning of sex or gender, usually because of ambiguity of the genital organs at birth. There is male intersex if the karyotype is 46,XY, female intersex if it’s 46,XX. For a plain-speaking but carefully detailed account of this difficult area, read the box, Girl or boy?, in WebPage 18. Incorporates hermaphrodism and pseudohermaphrodism, terms that are not much used outside the US.

interstitial cells See Leydig cells.

interstitial pregnancy An ectopic pregnancy located in the interstitial segment of the fallopian tube. An especially dangerous form of tubal pregnancy, because the surrounding myometrium of the uterus supports the pregnancy's growth for weeks without causing symptoms; when rupture eventually occurs it can be catastrophic, because a main branch of the main artery to the uterus is torn, with sudden (sometimes fatal) bleeding into the peritoneal cavity.

interstitial segment The innermost part of the fallopian tube, passing through the wall of the uterus (the myometrium) to join the isthmus to the endometrial cavity.

interstitial trophoblast See extravillous trophoblast.

intervillous space The space in the placenta in which the maternal blood flows. Washes around the chorionic villi, which contain blood capillaries from the fetus, so that oxygen and nutrition pass to the fetus, while carbon dioxide and waste pass to the mother. Formed from lacunae and lined by the syncytiotrophoblast.

intracytoplasmic sperm insertion (ICSI) An in vitro fertilization technique for overcoming infertility due to oligospermia or azoospermia involving sperm microinjection (SMI), in which one or more sperm are injected through the zona pellucida, across the perivitelline space, through the vitelline membrane (the egg cell’s membrane), and into the substance (or cytoplasm) of the egg itself. Has completely replaced subzonal sperm insertion (SUZI).

intramural segment See interstitial segment.

intrauterine adhesions Adhesions inside the endometrial cavity caused by prior infection (endometritis), especially if there has been a curettage during the period of infection, or if curettage is performed in conditions of low estrogen. The circumstances in which this combination is most common are treatment for a missed abortion and treatment of a postpartum hemorrhage (bleeding a few weeks after the birth of a baby). See also Asherman’s syndrome and endometrial atrophy. A cause of absent periods amenorrhea, light periods (hypomenorrhea) or recurrent miscarriages.

intrauterine insemination (IUI) A form of assisted conception involving assisted insemination into the uterus, either for donor insemination (DI) or with husband’s semen (AIH). IUI can be carried out with a woman’s natural cycles or with ovarian stimulation (superovulation) using clomiphene or follicle stimulating hormone, with ovarian monitoring.

IRB See institutional review board.

irritable bowel syndrome A distressing dysfunction of the intestines, in which there’s both overactivity of the involuntary contractions of the intestines” muscular wall and increased pain signals coming from those contractions. Treatment is based on decreasing the contractions (with a diet high in fiber, sometimes with antispasmodic drugs) and attempting to reduce the action of the pain-carrying nerves, both by sedating them (this means general sedation too, so it’s often not very acceptable) and by re-educating them to be less sensitive. Treatment is time consuming and, ultimately, not always satisfactory. The symptoms of the irritable bowel syndrome are often confused with those of endometriosis (to make the distinction read the box, Is the pain really endometriosis?, in WebPage 15); they are sometimes made worse with, and at the time of, premenstrual tension, or, in my experience of patients with it, by performance of a laparoscopy. Typically (but not always), there is an alternating tendency towards diarrhea or constipation; sometimes there is nausea with the spasms. Also called spastic colon.

isthmus The narrow, inner part of the fallopian tube, about 3 to 4 cm long; lies between the ampulla and the interstitial segment.

IUD Abbreviation either for intrauterine death (death of a fetus, prefacing a stillbirth) or for intrauterine (contraceptive) device, which, to resolve this ambiguity, is sometimes (though not in this book) abbreviated “IUCD’.

IUI See intrauterine insemination.

IVF See in vitro fertilization.

IVM See in vitro maturation.