A polymorphism for blood clotting factor "five" that makes coagulation occur more readily, therefore causing thrombophilia. Pronounced "Layden".

"Factor 13". A component of the coagulation system.

The hollow organ, about 10 to 12 centimeters long, that effectively joins the ovary to the uterus on each side. Composed of the fimbrial end, the ampulla, the isthmus and the interstitial segment.

Looking inside the fallopian tube with a tiny (half a millimeter diameter) flexible, fiberoptic instrument, from the direction of the uterus. See also salpingoscopy.

Technical speak for the monthly chance of pregnancy, or monthly fertility rate, either for an individual (measured over time) or for a population (the number of conceptions occurring in one month). For any individual with unexplained infertility and in milder cases of subfertility, chiefly determined by the duration of infertility (or, in cases of secondary infertility, in which past fecundability is being estimated, determined by time to pregnancy). Once calculated this way, an estimate of the chance of still getting pregnant naturally (as opposed to undergoing assisted conception) will chiefly be determined by the time left for conception.

Entry of a sperm cell into an egg: their "marriage". The egg is activated by this event, so that: (1) "cortical granules" are expelled that stop further sperm binding to the egg; (2) the second division of meiosis is completed, with expulsion of the second polar body; and (3) the machinery of the egg is got going, which will form pronuclei of the male and female chromosomes prior to syngamy.

Highly purified Metrodin, with no residual luteinising hormone, thus equivalent in activity to recombinant FSH. Called Metrodin HP outside the US. Made by Serono.

A controversial and emotionally hazardous way of dealing with a higher-order multiple pregnancy (such as quadruplets, quintuplets, or higher) in which, all the embryos or fetuses are at risk of being lost before viability. The technique involves carrying out transvaginal ultrasound and injecting a lethal substance (such as air or a solution of potassium) into the visibly beating heart of one or more of the embryos, so reducing the number of surviving embryos to three, two or one. Generally regarded as a more stressful procedure than even an induced abortion, both for the person undergoing the operation and for the ultrasound doctor asked to do it. Few people regard the availability of fetal reduction to mean that the greatest care does not need to be taken to avoid higher-order multiple pregnancies in assisted conception programs. There's a hazard: loss of the remaining fetuses from miscarriage; but the risk of this, with an experienced ultrasound doctor or fetal medicine specialist, is low.

An unborn baby. The product of conception from the time the embryo is fully formed (from head to limbs - about 8 weeks from the last menstrual period) - until delivery. Sometimes spelt foetus.

A polymer that is formed from the circulating protein fibrinogen when blood clots (see coagulation system). Also important in the formation of the placenta, so abnormalities of fibrinogen can cause recurrent miscarriage.

A very soluble protein found in the blood that forms the progressively less soluble protein fibrin when blood clots, through the action, first of thrombin and then of factor XIII.

A benign "tumor" of the muscular wall of the uterus (the myometrium). More common with increasing age, but can occur in women in their twenties. Can be single or multiple, and can be located on the outside of the uterus (a subserous fibroid), within the wall of the uterus (an intramural fibroid), or protruding into the cavity of the uterus (a submucous fibroid. The closer it is (or they are) to the endometrial cavity, the more likely it is that a fibroid will disturb reproduction (either as miscarriages or sometimes as infertility) and disturb menstrual bleeding. Surgery for removal of a fibroid, or myoma, is called a myomectomy.

Latin for a fringe, particularly the fringed, open end of the fallopian tube referred to as the fimbrial end. Plural: fimbriae.

Also "fimbriated end": the open, outside end of the fallopian tube in contact with the surface of the ovary, from which it "picks up" the ovulated egg from the ruptured follicle. It's composed of delicate fimbriae -- finger-like projections of the tube lined by cells with tiny hairs (cilia), which beat towards the inside of the tube, carrying the sticky cumulus mass containing the egg into the ampulla before fertilisation. Easily damaged by infection (salpingitis) or careless surgery, after which it may be blocked, resulting in a hydrosalpinx, or have its correct movement inhibited by adhesions.

An operation for sterilisation or "tubal ligation" in which the fimbrial end of each fallopian tube is removed. It has a higher failure rate than most other sterilisation operations on the tubes and it also is more difficult to reverse if the woman intends to regain fertility. It can result in a hydrosalpinx, which can jeopardise success with in vitro fertilisation, and the microsurgery operation to reverse it, salpingostomy, is much less often followed by pregnancy than tubal anastomosis operations are.

Microsurgery of the fallopian tube's fimbrial end, involving careful dissection of fimbriae that have become stuck together from adhesions. Generally gives a better outcome than salpingostomy (which must be resorted to if the fimbriae are too damaged to dissect).

Known as "FISH". A form of DNA testing for genetic diagnosis in which a special region of a chromosome is stained with a dye that emits colored light when exposed to ultraviolet light. For example, a marker for chromosome 21 will normally show two spots of light, whereas three spots of light would indicate trisomy 21 (Down syndrome). Useful because the technique is accurate with just one cell, making diagnosis possible in an IVF embryo before transfer (see preimplantation genetic diagnosis), and speeding up prenatal diagnosis while awaiting a full karyotype. Being replaced in some labs by comparative genomic hybridisation.

Normal structure in the ovary that contains the egg, or oocyte. All are formed as primordial follicles before birth and remain microscopic in size until growth starts (folliculogenesis), a month or two before the cycle in which the particular follicle will be a candidate to ovulate. About 3 mm in diameter at the start of a cycle, and about 2 cm in diameter when ready to ovulate. The follicle makes more and more estrogen (particularly estradiol) as it grows. In ovarian monitoring for assisted conception, the number growing and their rate of growth are monitored by transvaginal ultrasound.

Egg retrieval procedure for obtaining eggs (oocytes), involving the passing of a needle into a mature (or preovulatory follicle), either directly at laparoscopy or (more usually) via the vagina guided by transvaginal ultrasound.

Cells of the follicle that surround the egg (the oocyte). An increase in number is what causes the follicle to grow. In tertiary follicles they are responsible for converting androgens (from surrounding ovarian thecal cells) into estrogens, particularly estradiol. A tertiary follicle's cells are also called granulosa cells.

(FSH) The hormone, or gonadotropin, produced by the pituitary gland that in women stimulates the tertiary follicle to grow; in men it stimulates spermatogenesis. Obtained from human sources in a mixture with luteinising hormone (LH) as (1) human menopausal gonadotropin (hMG), extracted from the urine of women who have been through the menopause (Humegon, Metrodin and Pergonal); and (2) human pituitary gonadotropin (hPG), from human pituitary glands removed at autopsies (now obsolete). Today, pure FSH is made synthetically with gene technology (recombinant FSH), such as Gonal-F and Puregon.

Serial transvaginal ultrasounds of the ovary during the follicular phase to track the growth of one or more tertiary follicles, accompanied usually by serial estimations of serum estradiol, serum LH and serum progesterone, for the two-fold purpose of estimating follicular maturity (to time intercourse, a mid-cycle-dependent investigation such as a postcoital test, or an egg retrieval) and identifying the onset of the LH-surge, which can affect the timing of the intervention. Sometimes accompanied by injection of human chorionic gonadotropin to trigger ovulation at a precisely anticipated time.

The process by which a primary follicle or a tertiary follicle stops growing, leading to disappearance (apoptosis) of its follicle cells and the oocyte, or egg, they contain. Such a follicle is called an atretic follicle.

The part of the ovary's monthly cycle before ovulation, dominated by the presence of firstly, a cohort of growing tertiary follicles, then the dominant follicle, and the estradiol these follicles produce. Normally around 14 days in length, but quite variable, often being much longer for the first few menstrual cycles after the first period (menarche), and typically getting shorter in the months or years leading up to egg depletion and menopause. Corresponds with the proliferative phase of the endometrial, or menstrual cycle.

A follicle is "recruited" at two distinct stages of development. Early or continuous recruitment refers to the ongoing, continuous recruitment of primordial follicles to start their growth and become antral follicles, a process that is independent of major hormones, starts before birth and ends when there are no follicles left, this taking place around the time of menopause. Cyclical recruitment refers to the much later recruitment of medium-sized tertiary follicles into the ovarian cycle due to a temporary elevation of follicle stimulating hormone, which occurs at the end of each luteal phase, thus initiating a new follicular phase; the group of "recruits" susceptible to this late recruitment is called a cohort. Time-wise for a particular follicle, the two episodes of recruitment occur 8 months apart: in other words, it takes 8 months for a follicle to grow from its resting state before it can have a chance of making estrogen and then undergoing ovulation. Not all early-recruited follicles undergo later cyclical recruitment: some are lost through early atresia, many reach the stage at which they could be cyclically recruited at a stage when FSH is low (most stages of the ovarian cycle) and undergo atresia then. Readers will appreciate that ovulation induction, including intentional superovulation, can have no effect on the rate at which follicles are used up in ovaries or on the age at which menopause will occur (the different recruitment points involved are 8 months apart, with the early recruitment point governing the rate eggs are used up and the late recruitment point deciding how many follicles can respond to provide useable eggs.

Strictly, the process by which follicles are first formed in the ovaries before birth; in the woman, it means the growth of a primordial follicle into an early tertiary follicle -- a transition that confers receptiveness of the follicle to follicle stimulating hormone (FSH) The stimulus for initiation of follicular development and its timing for individual follicles remains a mystery.

Recombinant follicle stimulating hormone made by Organon. Called Puregon in Europe, Australia and Asia. On an equivalent dose basis, produces serum FSH that are somewhat slower to rise than with the use of hMG preparations, but which are ultimately higher: in other words, follicles and serum estradiol levels take a little longer to respond than they do to Humegon, but the number of mature, preovulatory follicles available for egg retrieval is the same or more. I find that 200 U (units) of Puregon per day produces a similar result to 225 U of Humegon or Metrodin. Generically known as follitropin beta.

Generic name for recombinant FSH, as found in Gonal-F (or follitropin alpha) and Puregon (Follistim), or follitropin beta. Although there are slight differences in the two preparations, their clinical action is equivalent.

The commonest cause of severe mental retardation in males, caused by a long "triple repeat sequence" in a part of a gene for intelligence located on an X-chromosome, rendering this sex chromosome susceptible to breakage, which can be revealed either in a karyotype performed under special laboratory conditions or using a special PCR DNA test; females have two X-chromosomes and so may be carriers for this devastating condition, which will affect one-in-two of their male children; the carrier state in females can have clinical effects, namely a susceptibility to reduced numbers of ovarian follicles and hence primary ovarian failure and premature menopause, so should be looked for before assisted conception attempts are made in these clinical circumstances.

Not often carried out at no cost, "free" here means the androgen (testosterone) in blood that is not bound to carrier proteins such as sex hormone binding globulin, so it's immediately available for action in the tissues. A more sensitive test than serum testosterone and likely to be increased in the polycystic ovary syndrome. An indirect measure of serum free testosterone, which can be performed instead.

The body, or the main part, of the uterus (i.e. the part of the uterus that is not cervix). Sometimes refers to the dome-shaped topmost part of the uterus.