Ultrasound imaging of the pelvic organs for diagnosing abnormalities of (particularly) the uterus and the ovaries; for monitoring the development of ovarian follicles with ovulation induction and assisted conception programs; and for following the course of early pregnancy. Among the pioneers were Dr Karl Popp, who used a mechanical sector scanner vaginally in Hamburg in 1984, and Dr John Anderson, who used the first vaginal linear array scanner at Sydney IVF in 1985, leading to its widespread use subsequently in Australia and the US.

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 localised 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.

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.

A uterine anomaly in which the Mullerian 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).

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.

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.

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.

(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.

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.

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 luteinising 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.

Due to trisomy 21. Chromosome 21 is the smallest of the "autosomes" (the non-sex chromosomes): trisomies of the other autosomes tend to be lethal at an earlier stage of embryonic or fetal development, and so are seen much more rarely. Diagnosis of Down's syndrome requires a karyotype, obtainable from pregnancy tissue by chorionic villus sampling (CVS) or amniocentesis. Screening for increased risk in pregnancy can be performed by triple screen or by looking for nuchal translucency at transvaginal ultrasound.

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.

Overgrowth of the endometrium, caused usually by prolonged action of estrogen unopposed by progesterone (i.e. prolonged anovulation), as is the case in, particularly, the polycystic ovary syndrome. Potentially dangerous, because it can turn to cancer of the endometrium. Can be suspected by an echogenic appearance of the endometrium on transvaginal ultrasound and is confirmed by pathological examination of tissue obtained at curettage.

A polyp of the endometrium (lining of the uterus), sometimes without symptoms, sometimes with abnormal bleeding such as intermenstrual bleeding, premenstrual spotting or heavy periods. A cause of infertility (and of failure of assisted conception to result in pregnancy). Diagnosable with transvaginal ultrasound.

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.

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.

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.

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 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 fertilisation in which the oocyte is 'empty', that is it loses its pronucleus, and either (1) the male pronucleus from a single fertilising 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 fertilising 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.

The proportion of transferred embryos in an in vitro fertilisation 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.

(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).

(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).

In our context, the frequent estimation of serum estradiol (or perhaps estimating the cervical score) and performance of transvaginal ultrasound to estimate how close a woman is to ovulation.

A measurement done at transvaginal ultrasound of tissue in the neck of the fetus; if excessive, it implies a substantially increased risk that the fetus is affected by Down syndrome and Turner syndrome.

The frequent estimation of serum estradiol (or perhaps estimating the cervical score) and performance of transvaginal ultrasound to estimate how close a woman is to ovulation.

(PCO) The full name (almost never used) is micro-polycystic ovaries: it's a diagnosis best made on transvaginal ultrasound, with lots of medium-sized follicles visible around the rim of the ovaries; can be part of the polycystic ovary syndrome. (The 'cysts' are not real cysts. Think of them as stalled follicles. They don't need to be treated.) A very common condition: about 20% of women have it, though only a few women have the full syndrome.

(PROST) A form of assisted conception in which in vitro fertilisation (IVF) is used to produce fertilisation of one or more recovered eggs (oocytes). Useful if the potential fertilising ability of sperm (spermatozoa) is in doubt. Transfer is made on the day after egg retrieval and IVF, before the fertilised egg divides (it's at the pronuclear stage); the transfer is made to the fallopian tube to obtain advantages similar to gamete intrafallopian transfer (GIFT) and is made possible by laparoscopy (with anesthesia) or, less successfully, by transvaginal ultrasound (without anesthesia). Synonymous with zygote intrafallopian transfer (ZIFT).

A fallopian tube obstructed at its outer, fimbrial end and containing pus as a result of acute salpingitis. If the infection does not settle promptly with antibiotics, and becomes an abscess, surgical drainage can be needed (performed at transvaginal ultrasound in the operating room or at laparoscopy, perhaps with a salpingectomy).

Measurement of estradiol in blood serum. Used especially for monitoring the development of ovarian follicles in assisted conception, usually together with transvaginal ultrasound. The cycle might be a natural one or, more usually, when there is ovulation induction or superovulation. The result should be available within 4 hours of the test for this purpose.

An early miscarriage, usually within a week or two of the period that had been expected. Traditionally, no curettage was needed; these days a subclinical miscarriage is one that has not resulted in a gestational sac visible on transvaginal ultrasound.

The third stage of growth of the follicle, in which the egg is enclosed by a thick layer of round-shaped follicle cells among which an antrum, or fluid-filled space, has formed; this antrum will come to dominate the size of the follicle. The first stage of the follicle visible with transvaginal ultrasound (when it reaches about 4 mm in diameter). Further growth of the early tertiary follicle is determined by follicle stimulating hormone. Synonym: antral follicle.

Tests that check if the fallopian tubes are open, usually by passing fluid through the cervix to fill the endometrial cavity and then demonstrate it coming out the ends of the tubes. The two common tests are to pass a blue dye at laparoscopy or a solution opaque to x-rays, namely a hysterosalpingogram. Once upon a time, carbon dioxide gas was used and listened for with a stethoscope (a Rubin's test); a high-tech version of Rubin's test uses transvaginal ultrasound to show the gas.

Traditionally, any bleeding from the uterus during pregnancy while the cervix is (still) closed. Today, as well, there would need to be a normal embryo and, a little later, normal fetal heart movement pattern on transvaginal ultrasound to separate it from an inevitable miscarriage.

A computer enhanced transvaginal ultrasound or a multi-probe abdominal ultrasound that produces a composite, constructed three-dimensional image of the uterus, which can then be viewed from any perspective. Excellent for displaying the form of the uterus in the investigation of uterine anomalies and recurrent miscarriages.

The womb, in which pregnancy is gestated from the time of implantation of the embryo until delivery or miscarriage; formed from the joining of the two Mullerian ducts (in the absence of anti-Mullerian hormone); composed of the main, upper part (the uterine fundus) and a lower neck, or cervix, which connects it to the upper part of the vagina; most of its wall is made of muscle tissue (the myometrium), but with an inner lining of glands (the endometrium) and, on the outer surface, a thin covering of uterine serosa. Best seen on transvaginal ultrasound, especially a three-dimensional ultrasound; its cavity is best displayed with a hysterosalpingogram (or, strictly, a hysterogram).

A sac-like structure attached to the under-surface of the developing embryo. The first part of the embryo to become visible on transvaginal ultrasound after the gestational sac, but not by itself as reassuring as seeing a beating fetal heart that the pregnancy will most likely avoid miscarriage. Not as important for a human embryo's nutrition as it is for a fertilised egg incubated by a hen, and in mammals contains no yolk, but the yolk sac's lumen is continuous with the lumen of the embryo's developing gut, or intestine, and shares an absorptive function. Cells from the yolk sac become incorporated into the fetus in many ways, including forming the primitive germ cells.

(ZIFT) A form of assisted conception in which in vitro fertilisation (IVF) is used to produce fertilisation; transfer is made on the day after egg retrieval and IVF, before the fertilised egg divides (it's at the zygote, or pronuclear stage). Useful if the potential fertilising ability of sperm is in doubt. The transfer is made to the fallopian tube to obtain advantages similar to gamete intrafallopian transfer (GIFT) and is made possible by laparoscopy (with anesthesia) or by transvaginal ultrasound (without anesthesia). Synonymous with pronuclear-stage transfer (PROST).