Obstetrician-Gynecologist (OB-GYN) — A doctor who specializes in the diseases and the routine physical care of the reproductive system of women, including treating women through pregnancy and childbirth.

Obstructive Azoospermia — The result of a blockage in the male reproductive tract. Sperm production may be normal but the sperm are trapped inside the epididymis. See Azoospermia.

OHSS — See Hyperstimulation.

Oligomenorrhea — Infrequent menstrual periods.

Oligo-ovulation — Infrequent ovulation, usually less than six per year.

Oligospermia — Having few sperm.

OPK/OPT — See Ovulation Predictor Kit/Test.

Oocyte (Egg) — The female reproductive cell.

Oophorectomy — Surgical removal of the ovaries.

Ovarian Failure — The failure of the ovary to respond to FSH stimulation from the pituitary because of damage to or malformation of the ovary. Diagnosed by elevated FSH in the blood.

Ovarian Cyst — A fluid-filled sac inside the ovary. An ovarian cyst may be found in conjunction with ovulation disorders, tumors of the ovary, and endometriosis. See also Chocolate Cyst.

Ovarian Drilling — During a laparoscopy, an electrosurgery needle is used to burn 10-12 small holes into each ovary. This procedure may help reduce androgen levels and restore cycles in women with polycystic ovaries.

Ovarian Hyperstimulation Syndrome (OHSS) — See Hyperstimulation.

Ovarian Wedge Resection — Surgical removal of a pie-shaped wedge of a polycystic ovary in order to help ovulation.

Ovary — The female gonad; produces eggs and female hormones.

Ovulation — The release of the egg (ovum) from the ovarian follicle.

Ovulation Induction — Medical treatment performed to initiate ovulation. See also Clomiphene Citrate, Humegon, Pergonal, Repronex, Follistim, Gonal-F, Fertinex and Metrodin.

Ovulation Predictor Kit/Test — A test kit a woman can use at home to predict forthcoming ovulation based on a surge of luteinizing hormone.

Ovulatory Dysfunction — A problem existing in the ovary where either something is abnormal in the process of developing the follicle or the egg is not released from the follicle.

Ovulatory Failure (Anovulation) — The failure to ovulate.

Ovum — The egg; the reproductive cell from the ovary; the female gamete; the sex cell that contains the woman’s genetic information.