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.

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

An assisted conception procedure in which unfertilised eggs plus sperm (i.e. gametes) are transferred to the fallopian tube, so that fertilisation occurs in the normal place. Because in vitro fertilisation 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.

A GnRH-antagonist made by Organon. The first to be FDA approved for women undergoing in vitro fertilisation), 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 luteinising hormone. Marketed as Antagon in the US and as Orgalutran elsewhere.

A step of major reorganisation 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).

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.

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.

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.

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 next generation. 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 fertilisation the contributing sperm and egg are haploid.

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).

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 fertilisation, 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.

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.

A GnRH-analog that briefly stimulates the pituitary gland to release follicle stimulating hormone (FSH) and luteinising 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).

Synthetic hormones related to the natural hormone GnRH, or gonadotropin releasing hormone.

A GnRH-analog that (unlike GnRH-agonists) immediately stops the pituitary gland from releasing the gonadotropins follicle stimulating hormone (FSH) and luteinising 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 luteinising hormone is added to the stimulation regimen.

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

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.

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 luteinising 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.

A hormone produced by the hypothalamus of the brain to regulate production and release of the gonadotropins follicle stimulating hormone and luteinising 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.

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

High responder: discussed under low responder.

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

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

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.

Ovarian follicle cells from a tertiary follicle.

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).