## DEFINITIONS

**Assisted reproductive technology (ART):** All treatments or procedures
that include the *in vitro* handling of human oocytes and sperm or
embryos for the purpose of establishing a pregnancy. ART does not
include artificial (intrauterine) insemination.

**Biochemical pregnancy:** Evidence of conception based only on
biochemical data in the serum or urine before ultrasound evidence of a
gestational sac.

**Blastocyst:** An embryo with a fluid-filled blastocoele cavity
(usually developing by five or six days after fertilization).

**Cancelled cycle:** An ART cycle in which ovarian stimulation or
monitoring has been carried out with the intent of undergoing ART but
which did not proceed to follicular aspiration, or in the case of a
thawed embryo, to transfer.

**Clinical pregnancy rate:** Number of clinical pregnancies expressed
per 100 initiated cycles, aspiration cycles, or embryo transfer cycles.
When clinical pregnancy rates are given, the denominator must be
specified.

**Clinical/definitive pregnancy:** Evidence of pregnancy by clinical
(fetal heartbeat) or ultrasound parameters (ultrasound visualization of
a gestational sac, embryonic pole with heartbeat). It includes ectopic
pregnancy. Multiple gestational sacs in one patient are counted as one
clinical pregnancy.

**Clomiphene citrate:** An anti-estrogen drug used to induce ovulation.

**Controlled ovarian hyperstimulation (COH):** Medical treatment to
induce the development of multiple ovarian follicles to obtain multiple
oocytes at follicular aspiration.

**Donor oocyte:** Oocytes or embryos arise from assisted reproductive
technology (ART) cycle of a donor patient (or couple) and are
transferred into a recipient.

**Ectopic pregnancy:** A pregnancy in which implantation takes place
outside the uterine cavity.

**Embryo transfer (ET):** Procedure in which the embryo(s) are placed in
the uterus or fallopian tube.

**Embryo transfer cycle:** Assisted Reproductive Technology (ART) cycle
in which one or more embryos are transferred into the uterus or
fallopian tube.

**Embryo:** Product of conception from the time of fertilization to the
end of the embryonic stage eight weeks after fertilization.

**Endometrium:** Uterine lining sheds monthly to produce a menstrual
period.

**Estrogen:** The female sex hormone produced by the ovaries,
responsible for the development of female sex characteristics. Estrogen
is largely responsible for stimulating the uterine lining to thicken
during the first half of the menstrual cycle in preparation for
ovulation and possible pregnancy.

**Fertilization:** The penetration of the ovum by the spermatozoon and
fusion of genetic materials resulting in the development of a zygote.

**Follicle-stimulating hormone (FSH):** The pituitary hormone
responsible for the stimulation of estrogen production from the follicle
cells around the egg.

**Gestational sac:** A fluid-filled structure containing an embryo that
develops early in pregnancy usually within the uterus.

**Gonadotropin-releasing hormone (GnRH):** A hormone secreted by the
hypothalamus that prompts the pituitary gland to release follicle
stimulating hormone and luteinizing hormone into the blood stream.

**Human chorionic gonadotropin (hCG):** A hormone produced by the
placenta during pregnancy that is often used with clomiphene or hMG to
cause ovulation.

**Human menopausal gonadotropin (hMG):** An ovulation drug containing a
mixture of follicle stimulating hormone and luteinizing hormone derived
from the urine of postmenopausal women.

**Hypothalamus:** A thumb-sized area in the base of the brain that
regulates the pituitary.

***In vitro* fertilization (IVF):** An Assisted Reproductive Technology
(ART) procedure that involves *extracorporeal* fertilization.

**Infertility:** Failure to conceive after at least one year of
unprotected *coitus* (intercourse).

**Intracytoplasmatic (intracytoplasmic) sperm injection (ICSI):** IVF
procedure in which a single spermatozoon is injected through the zona
pellucida into the oocyte.

**Intrauterine Insemination (IUI):** Placement of spermatozoa that have
been separated from the seminal fluid into the endometrial cavity
through a small catheter.

**Live birth:** A birth in which a fetus is delivered with signs of life
after complete expulsion or extraction from its mother, beyond 20
completed weeks of gestational age. (Live births are counted as birth
events, e.g. a twin or triplet live birth is counted as one birth
event.)

**Live-birth delivery rate:** Number of live-birth deliveries expressed
per 100 initiated cycles, aspiration cycles or embryo transfer cycles.
When delivery rates are given, the denominator must be specified.

**Luteinizing hormone (LH):** The hormone that triggers ovulation and
stimulates the corpus luteum to secrete progesterone.

**Micromanipulation** (also referred to as **assisted fertilization):**
The use of special micromanipulative technology that allows operative
procedures to be performed on the oocyte, sperm or embryo.

**Oocyte:** An immature female reproductive cell, one that has not
completed the maturing process to form an ovum (gamete).

**Ovarian Hyperstimulation Syndrome (OHSS):** Ovarian enlargement to a
diameter of more than 6 cm as a result of stimulation of multiple
follicles. This condition may be fatal in severe cases.

**Ovulation:** The expulsion of a mature egg from its follicle in the
outer layer of the ovary. It occurs on approximately day 14 of a 28-day
cycle and is usually determined clinically by a serum progesterone
level.

**Pituitary gland:** A small gland just beneath the hypothalamus that
secretes follicle stimulating hormone and luteinizing hormone, which
stimulate egg maturation and hormone production by the ovary.

**Progesterone:** An ovarian hormone secreted by the corpus luteum
during the second half of the menstrual cycle. Progesterone helps
prepare the endometrium to receive and nourish an embryo.

**Semen Analysis:** Quantitation of various parameters of a recently
ejaculated semen specimen analyzed after liquefaction has occurred.

**Ultrasound:** High frequency sound waves that produce an image on a
monitor screen of internal organs.

**Zygote:** The diploid cell, resulting from the fertilization of an
oocyte by a spermatozoon, which subsequently develops into an embryo.