Obstetrician-gynecologist (Ob-gyn)
A physician who specializes in the treatment of female disorders and pregnancy.

Oligomenorrhea
Infrequent and irregular menstrual cycles.

Oligo-ovulatory
A term describing a woman who ovulates infrequently.

Oligospermia
A low sperm count.

Ongoing pregnancy
A clinical pregnancy which is continuing but undelivered at time of reporting.

Oocyte
The immature ovum, the unfertilized female gamete or sex cell (egg) produced in the ovaries each month, that contains the genetic information to be transmitted by the female.

Oocyte retrieval
A surgical procedure to collect the eggs contained within the ovarian follicles, either via laparoscopy or ultrasound-guided follicular aspiration through which a needle is inserted into the follicle, the fluid and egg are aspirated into the needle, and then placed into a culture medium-filled dish.

Oolemma
The plasma membrane of the oocyte.

Ovarian cyst
A fluid-containing enlargement of the ovary.

Ovarian failure
The inability of the ovary to respond to any gonadotropic hormone stimulation, usually due to the absence of follicular tissue on a genetic basis or postmenopausal condition (absence of oocytes).

Ovarian reserve
The biologic “age” of an individual’s oocytes: diminished ovarian reserve, which may be reflected by an elevated early follicular phase FSH and/or estradiol level, correlates with reduced chances for success following in vitro fertilization.

Ovarian wedge resection
Surgical removal of a portion of a polycystic ovary to produce ovulation.

Ovaries
The sexual glands of the female which produce the hormones estrogen and progesterone, and in which the ova are developed.

Ovary
The female gonad; produces eggs and female hormones.

Ovulation
The release of a ripened egg from its follicle.

Ovulation Induction
A type of infertility treatment that uses hormone therapy to stimulate oocyte (egg) development and release.

Ovulation induction or controlled ovarian hyperstimulation (COH)
Pharmacologic stimulation of the ovaries, generally with gonadotropins and/or clomiphene citrate, with the objective of stimulating the development of multiple follicles and hence multiple eggs.

Ovum
The unfertilized female gamete or sex cell (egg) produced in the ovaries each month, that contains the genetic information to be transmitted by the female.

Ovum donation cycle (standard)
A Donor/Recipient IVF cycle in which the eggs retrieved from the donor are transferred to one recipient after fertilization.