(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. 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).

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).

Nonsteroidal anti-inflammatory drugs, e.g. aspirin, ibuprofen (Advil, Nurofen etc), mefanamic acid (Ponstan), naproxen sodium (Aleve, Naprosyn, or in Naprogesic in combination with dextropropoxyphene), which stop the production of prostaglandins; useful for dysmenorrhea and prior to a hysterosalpingogram. Excessive use at the time of ovulation might predispose to a luteinised unruptured follicle, so NSAIDs should not be used for ovulation pain if you are trying to get pregnant.

An x-ray like a hysterosalpingogram in which a catheter is passed through the cervix and uterus, and then wedged into the fallopian tube to fill it with fluid visible on x-ray. High pressure can be applied, so some tubes that seem blocked on hysterosalpingogram (or on passing dye at laparoscopy) can be shown in fact to be open.

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.

Overcoming a localised obstruction of the isthmus or the interstitial segment of the fallopian tube by pushing a wire or a catheter through it, enabling (in some cases) the tube to be 're-canalised' and so to remain open after being blocked before; it's an attractive alternative to tubal anastomosis and can be performed either during the investigation of tubal infertility with hysteroscopy, laparoscopy and falloposcopy or at the time of carrying out a hysterosalpingogram. Because not all tubes that seem to be blocked are in fact blocked (sometimes a normal tube will not allow fluid to pass through it for hormonal reasons or because of a spasm), care needs to be taken to investigate the tube properly before canalisation is undertaken.

Infertility for which no obvious cause has been found after the following tests have been done with normal results: a sperm count or postcoital test; a test of ovulation, such as a serum progesterone that is satisfactorily high; and a laparoscopy (used to show that the tubes are open and that there is no endometriosis or other obvious abnormality). Although a hysterosalpingogram (HSG) can substitute for laparoscopy in excluding blockage of the fallopian tubes, an HSG can miss peritubal adhesions and will miss endometriosis. Infertility should not be considered unexplained unless a thorough, careful laparoscopy has been done.

A uterine anomaly that comes about when the uterus forms (in the embryo) from just one Mullerian duct; the uterus will be a little smaller than normal (making a miscarriage or premature labor more likely), and will be connected by a fallopian tube to just one ovary, contributing slightly to infertility (since, on average, only half of ovulations have a chance of resulting in pregnancy). Reproduction, however, can be normal, and a woman might go through life with a unicornuate uterus and not know it. Diagnosed by hysteroscopy and laparoscopy, by hysterosalpingogram or -- particularly effectively -- by three-dimensional ultrasound. Often there is a simultaneous abnormality of the kidneys, such as one kidney instead of two, diagnosable by abdominal ultrasound or, more specifically, by a special kidney x-ray study called an intravenous pyelogram.

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).