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justice In this book, the ethical value to be had in a community from conferring rights and obligations in a way that’s fair and accords to other ethical values (e.g. non-maleficence, beneficence). See also distributive justice.

Kallmann's syndrome Congenital absence of gonadotropin releasing hormone in the hypothalamus (causing, in women, primary amenorrhea and anovulation and, in men, failure of puberty) in combination with a congenitally absent sense of smell.

Kartagener's syndrome See immotile cilia syndrome.

karyotype A test that displays the chromosome after relevant cells are grown in tissue culture. A normal female karyotype is designated 46,XX and a normal male karyotype 46,XY. Examples of karyotypes are illustrated in WebPage8.

Klinefelter syndrome A trisomy with a karyotype of 47,XXY -- i.e. a male with an extra X-chromosome. A cause of azoospermia.

Kremer test An in vitro (laboratory) test of the interaction between sperm and cervical mucus, in which the mucus to be tested is drawn into two fine glass tubes (another two tubes are filled with mucus that is known to be good) to give a 4-way test between: husband’s (or male partner’s) sperm and wife’s (or female partner’s) mucus; husband’s sperm and known good mucus; known good sperm with wife’s mucus; known good sperm with known good mucus. Because of the laboriousness of the test it’s usual to administer estrogen for at least a week in the follicular phase to ensure that the mucus is optimal.

K-selection A reproductive strategy where survival of a species is optimized by placing a premium on individual survival despite fluctuations of the environment. Favors large animals (and large animals favor this strategy) -- animals that get pregnant more than once and the offspring of which require postnatal care before sexual maturity is reached. Spacing of pregnancy is important for survival of mother and offspring, and thus favors the evolution of a genetic basis for subfertility -- an intriguing notion that's the theme of WebPage 2. The opposite reproductive strategy to r-selection. The word comes from the environment's Karrying capacity.

 

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lacunae Latin for “lakes”: one lacuna, two lacunae. Refers particularly to spaces that form within the syncytiotrophoblast (which therefore continues to line the spaces), separating the SCT into strips of land and little peninsulas that will develop into chorionic villi, as the lakes coalesce into one large intervillous space, into which maternal arteries will open, delivering blood to the placenta as it is being formed.

laparoscopy A “minimally invasive” surgical operation at which instruments are passed through the wall of the abdomen: (1) for the diagnosis of abnormalities of the abdominal or pelvic organs (such as the fallopian tubes, ovaries and uterus) and to diagnose endometriosis; or (2) therapeutically, to reach the fallopian tubes for certain assisted conception procedures (see gamete intrafallopian transfer and zygote intrafallopian transfer). Carries the risks of surgery (damage to internal organs, hemorrhage, infection) and the risks of general anesthesia.

laparotomy A surgical operation in which the abdomen is opened. Needed for microsurgery operations on the fallopian tubes (although some operations formerly done only at laparotomy are now possible at laparoscopy). For infertility surgery, the scar from a laparotomy is usually a low, horizontal one, just above the pubic bone. Several days in hospital are needed; most people are off work about 3 weeks; and some numbness or sensitivity below the scar can be expected for several months, as nerves to the skin regrow.

large bowel The colon; see bowel.

last menstrual period (LMP) The normal period immediately preceding conception. For convenience, obstetricians calculate the duration of a pregnancy as starting with this date, even though of course it does not truly begin until fertilization (or, some would say, implantation). See also implantation bleeding.

leukemia inhibitory factor (LIF) A signalling molecule originally discovered in association with leukemia, but now known to have many functions, including the support of pregnancy by the endometrium as it forms decidua.

leuprolide See leuprorelin.

leuprorelin A GnRH agonist made by Abbott and sold as Lupron in the US. Called leuprorelin in Australia and Europe, and sold there as Lucrin. Administered by daily injection under the skin or as a depot preparation once per month.

Leydig cells Cells of the testis lying between the testicular tubules in which sperm are formed (hence their other name, interstitial cells), and responsible for the production of the male sex hormone testosterone under the influence of luteinizing hormone.

LH surge A sudden and huge increase in production of luteinizing hormone by the pituitary gland in response to sustained and substantial levels of estradiol in the blood in women, midway through the ovarian cycle. Causes ovulation about 36 hours after it starts (about 20 hours after its peak). If not suppressed during assisted conception (see GnRH-agonists and GnRH-antagonists) it can start before human chorionic gonadotropin has been given, so spoiling the timing of egg retrieval. Timely production of the LH surge in adult women depends on female conditioning of the hypothalamus and/or the pituitary gland before birth. Detectable by testing the urine with a special kit, described in WebPage 19. See also follicle tracking.

LH See luteinizing hormone.

LIF See leukemia inhibitory factor.

linkage analysis Read chromosomal cross-over first, then come back. Because it can take lots of cross-overs (i.e. lots of generations) to send two genes that live as neighbours on a chromosome into different directions (i.e. they end up in different people), we can do family studies to work out how closely people are related by seeing how long the runs are of identical genes.

LMP See last menstrual period.

long protocol A treatment protocol for using GnRH-agonists that involves their use for more than a week before injections of follicle stimulating hormone (FSH) start for induction of superovulation in assisted conception programs. The advantage is that any temporary rise in luteinizing hormone levels and progesterone levels has dissipated before the development is under way of those ovarian follicles from which eggs will be obtained at egg retrieval. The disadvantage, compared with the short protocol, is that higher (hence more expensive) doses of GnRH-agonist and FSH are needed. The GnRH can be started with menstruation or during the luteal phase of the previous cycle. See also ultrashort protocol. The details are in the box, The long, short and ultrashort of GnRH-agonists, in WebPage 20.

low responder Early experience with superovulation for in vitro fertilization, particularly at the original US program in Norfolk VA, saw women patients classified into three classes of responders, depending on how many eggs were obtained at egg retrieval. Poorer than usual outcomes could occur with either a low response or a high response (the high responders generally have polycystic ovaries, with a risk of ovarian hyperstimulation syndrome (OHSS). Many maneuvers have been used to try and retrieve more eggs among low responders, such as starting high dose FSH on day 1, the adding of growth hormone, the avoidance of GnRH-agonists etc., all generally without improving the results. Day 3 serum FSH levels can be high in low responders, indicating a depletion of eggs in the ovaries.

LPD See luteal phase defect.

Lucrin See leuprorelin.

LUF See luteinized unruptured follicle.

lumen The hollow center of a cylindrical organ or tissue, such as that of a fallopian tube or a blood vessel. Adjective: luminal.

Lupron See Lucrin.

lupus anticoagulant An antibody first noted in the disease systemic lupus erythematosus or “lupus”, that has the ability to stop blood clotting. A cause of recurrent miscarriages. Closely related to a family of anti-phospholipid antibodies, especially anticardiolipin antibody. Also called the lupus inhibitor.

luteal phase defect (LPD) A luteal phase that is shorter than optimal for a fertilized egg to undergo implantation. Very likely if the luteal phase is shorter than normal (11 to 16 days), but not all luteal phases within this range are innocent. Often caused by a prior defect of the follicular phase or of the development of the ovulating tertiary follicle (the preovulatory follicle) and hence there can be a defect of the egg itself (if ovulation has actually occurred) or there can be a luteinized unruptured follicle -- any of which will either increase the risk of miscarriage or will prevent pregnancy altogether for that cycle. Synonymous with luteal phase insufficiency.

luteal phase The part of the ovarian cycle between ovulation and the start of a new follicular phase, so dominated by the presence of the corpus luteum and the progesterone it produces. Normally between 11 and 16 days in length. Extended by the action on the corpus luteum of human chorionic gonadotropin (hCG) if implantation of the embryo is successful. Shorter cycles can interfere with implantation (a luteal phase defect). Corresponds with the secretory phase of the menstrual cycle.

luteinized unruptured follicle (LUF) Occurs when a reasonably mature tertiary follicle (or preovulatory follicle) receives an LH surge that’s enough to make it start producing progesterone, but is not enough to cause it to release its egg through ovulation. The result is that the egg is trapped in the follicle, which to a greater or lesser extent then functions like a corpus luteum, though this stage of the follicle’s life is often shorter, giving rise to a luteal phase defect (LPD). For more (and for the conditions its common in), read the box, Fake ovulation, in WebPage 7.

luteinizing hormone (LH) The hormone, or gonadotropin, produced by the pituitary gland to cause, in women, ovulation of a mature follicle in the ovary, resulting in formation of the corpus luteum; in men, stimulates the production of testosterone by the Leydig cells of the testis. Suppressed by GnRH-agonists and GnRH-antagonists, so that (for ovulation induction) an injection of human chorionic gonadotropin (hCG), which acts the same way, has a predictable time course of action. A small amount of LH is essential for normal function of the tertiary follicle and the corpus luteum. See also LH surge and serum LH. Recombinant LH is under development by Serono as Luveris, but its clinical role in place of hCG is not yet established.

lutropin Generic name for recombinant luteinizing hormone. See Luveris.

Luveris Recombinant luteinizing hormone (LH) made by Serono.