Helpful terms

in alphabetical order

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  • Adhesions

    Scar tissue in and around the inside of the pelvic region. Adhesions may interfere with transport of the egg and / or implantation of the embryo in the uterus.

  • Amenorrhea

    Refers to a woman who has never had a menstrual period.

  • Anovulation

    The failure to ovulate.

  • Antibodies

    Proteins made by the body to attack or fight foreign substances. Antibodies normally prevent infection; however they can be made against sperm, sometimes causing fertility problems. Either the male or female partner may produce sperm antibodies.

  • Antisperm antibodies

    Antisperm antibodies attach themselves to the sperm and can inhibit movement. In men, this is sometimes in response to injury or surgery to the testes when the blood-sperm barrier has been breached. Antisperm antibodies may impair the sperms' ability to fertilize an egg

  • Assisted Hatching

    A small hole is made in the outer shell around the embryo (the zona pellucida) before transfer to the uterus

  • ART (Assisted Reproductive Technology)

    A term used to describe advanced scientific interventions, such as IVF, which are used to treat infertility

  • A type of fertility treatment in which sperm is washed and injected directly into the uterus around the time of ovulation.


  • Blastocyst

    A stage of embryo development approximately 5 or 6 days after egg collection.

  • Blastomere

    A single cell within a pre-implantation embryo up to the morula stage of development. Each blastomere is totipotent and has the ability to develop into a whole embryo if it was removed and grown on its own.

  • Blighted ovum

    A non-viable pregnancy which shows a gestational sac with no fetus on ultrasound.

  • Beta hCG test

    A blood test used to detect early pregnancy and to monitor progress of the pregnancy during the first weeks


  • Canceled cycle

    An ART cycle in which ovarian stimulation was carried out but was stopped before eggs were retrieved. Cycles are canceled for many reasons: there may be too few or too many eggs developing; the uterine lining may not be optimal for embryo replacement; the patient may become ill; or the patient may choose to stop treatment.

  • Chromosome

    A thread-like strand of DNA and protein the nucleus of the cell that carries genetic information. Humans have 23 pairs of chromosomes in each cell of their bodies (apart from a mature egg and sperm which have 23 single chromosomes)

  • Clomiphene

    Citrate A fertility drug taken orally that stimulates ovulation through the release of gonadotropins from the pituitary gland.

  • Compaction

    A stage of early embryo development between the 8-cell and the blastocyst stage. Around Day 4 of in vitro culture, when the embryo consists of approximately 8 cells, the cells merge together and this is called compaction. At this stage the embryo is referred to as a morula.

  • Corpus Luteum

    After ovulation, the follicle from which the egg was released is referred to as a Corpus Luteum. The Corpus Luteum produces progesterone, which is responsible for preparing and supporting the uterine lining for implantation.

  • Cryopreservation

    Freezing embryos from a couple's ART cycle.

  • Cumulus Oophorus

    A protective layer of cells surrounding the egg.


  • D & C (Dilation & Curettage)

    D & C is a minor surgical procedure in which the physician first dilates or opens the cervix and then inserts a thin spoon shaped instrument and uses it to remove material from the internal lining of the uterus. Dilation therefore stands for opening the cervix and curettage means the scraping of the uterine wall.

  • Donor egg cycle

    An embryo is formed from the egg of one woman (the donor) and then transferred to another woman who is unable to use her own eggs (the recipient). The donor relinquishes all parental rights to any resulting offspring.

  • Dysmenorrhea

    Painful menstruation; may be a sign of endometriosis.


  • Ectopic pregnancy

    A pregnancy in which the fertilized egg implants in a location outside of the uterus—usually in the fallopian tube, the ovary, or the abdominal cavity. Ectopic pregnancy is a dangerous condition that must receive prompt treatment.

  • Egg

    A female reproductive cell, also called an oocyte or ovum.

  • Egg Donation

    See Donor Egg Cycle.

  • Egg retrieval (oocyte retrieval)

    A surgical procedure to collect the eggs contained in the ovarian follicles.

  • Ejaculate

    Semen discharged during the process of ejaculation.

  • Ejaculation

    The expulsion of seminal fluid from the uthrethra of the penis during orgasm.

  • Embryo

    An egg that has been fertilized by a sperm and undergone one or more divisions.

  • Embryologist

    A highly trained scientist specializing in reproductive laboratory procedures.

  • Embryo transfer

    Placement of embryos into a woman's uterus through the cervix after in vitro fertilization.

  • Endocrinology

    The study of the body's hormone secreting glands.

  • Endometrium

    The lining of the uterus that grows thick each month and is lost through menstruation or remains intact to nurture an embryo if conception takes place.

  • Endometriosis

    A medical condition involving the presence of tissue similar to the uterine lining in locations outside of the uterus, such as the ovaries, fallopian tubes, and abdominal cavity, which may contribute to infertility.

  • Estrogen

    Female sex hormone produced by the ovary.


  • Fallopian Tubes

    Ducts through which eggs travel to the uterus from the ovary after they are released from a follicle. This is where fertilization normally occurs inside the body when sperm swims up the tube and meets the egg.

  • Fibroid

    A fibrous non-malignant tumor in the uterus. May affect fertility.

  • Fertilization

    The penetration of the egg by the sperm and the resulting combination of genetic material before an embryo is formed.

  • Fetus

    The unborn offspring from the eighth week after conception to the moment of birth.

  • Follicle

    A fluid-filled structure in the ovaries that contains a developing egg.

  • Follicle Stimulating Hormone (FSH)

    A hormone produced by the pituitary gland that stimulates egg maturation in the ovaries.

  • Fragmentation (of embryos)

    Sometimes when a cell divides in the pre-implantation embryo it is not a clean split and small fragments of cell are lost. Microscopically, this gives the embryo a poorer appearance, leading to a lower grade. Fragmented embryos are less likely to implant than those without any fragmentation. We will always choose the least fragmented embryos for transfer.

  • Frozen embryo cycle

    An ART cycle in which frozen (cryopreserved) embryos are thawed and transferred to the woman.


  • Gamete

    A reproductive cell and either a sperm or an egg.

  • Gestation

    The period of time from conception to birth.

  • Gestational carrier (a gestational surrogate)

    A woman who carries an embryo that was formed from the egg of another woman. The gestational carrier usually has a contractual obligation to return the infant to its intended parents.

  • Gestational sac

    A fluid-filled structure that develops within the uterus early in pregnancy. In a normal pregnancy, a gestational sac contains a developing fetus.

  • Gonadotropins

    Hormones that control reproductive function. Human menopausal Gonadotropin (HMG), Follicle stimulating hormone (FSH) and Luteinizing hormone (LH).

  • Gonadotropin Releasing Hormone (GnRH)

    A substance released from the hypothalamus in a pulsatile manner approximately every 90 minutes. This hormone acts on the pituitary gland enabling it to secrete LH and FSH, which stimulate the gonads.


  • Hatching (of embryos)

    Before an embryo can implant in the uterus, it must first escape from its outer shell (zona pellucida); this process is called hatching.

  • Hirsutism

    Overabundance of hair growth often found in woman with excess androgens.

  • Host uterus (Gestational Carrier or Surrogate)

    A couple's embryo may be transferred into another woman's uterus who then carries the pregnancy to term and returns the baby to the genetic parents immediately after birth.

  • Human chorionic gonadotropin (hCG)

    This hormone is produced during early pregnancy and keeps the corpus luteum producing progesterone. hCG is also used to trigger ovulation during fertility treatments.

  • Hyperstimulation

    The stimulation of multiple ovulations with fertility drugs.

  • Hyperthyroidism

    Overproduction of thyroid hormone by the thyroid gland. This leads to an increase in metabolism and can cause estrogen to ‘burn up' too rapidly, thereby interfering with ovulation.

  • Hypothalamus

    A part of the brain that is the “hormonal regulation center.” The hypothalamus is located adjacent to and just above the pituitary gland.

  • Hypothyroidism

    Underproduction of thyroid hormone by the thyroid gland. The resulting lowered metabolism can interfere with the normal breakdown of hormones and may lead to lethargy. Women may suffer from elevated levels of prolactin and estrogen, which can interfere with fertility.

  • Hysterectomy

    Surgical removal of the uterus.

  • Hysterosalpingogram

    A procedure used to assess the anatomy of the cavity of the uterus and the fallopian tubes.

  • Hysteroscopy

    A thin telescope is passed through the cervix and is used to visualize the inside of the uterus.


  • ICSI (intracytoplasmic sperm injection)

    A procedure in which a single sperm is injected directly into an egg; this procedure is most commonly used to overcome male infertility problems.

  • Induced or therapeutic abortion

    A surgical or other medical procedure used to end a pregnancy.

  • A type of fertility treatment in which sperm is washed and injected directly into the uterus around the time of ovulation.

  • An ART procedure that involves removing eggs from a woman's ovaries and fertilizing them outside her body. The resulting embryos are then transferred into the woman's uterus through the cervix.


  • No terms available


  • Karyotyping

    A test performed to analyze chromosomes for the presence of genetic defects.

  • Klinefelter's Syndrome

    A genetic abnormality characterized by having one Y (male) chromosome and two X (female) chromosomes. This condition may cause a fertility problem.


  • Laparoscopy

    A surgical procedure in which a fiber optic instrument (a laparoscope) is inserted through a small incision in the abdomen to view the inside of the pelvis.

  • Live birth

    The delivery of one or more babies with any signs of life.

  • Luteal Phase

    Post-ovulatory phase of a woman's cycle. The corpusluteum produces progesterone, which cause the uterine lining to thicken to support the implantation and growth of the embryo.

  • Luteal Phase Defect (or deficiency)

    A condition that occurs when the uterine lining does not develop adequately due to inadequate progesterone stimulation or because of the inability of the uterine lining to respond to progesterone stimulation.LPD may prevent embryonic implantation or cause an early abortion.

  • Luteinizing hormone (LH)

    A pituitary hormone that stimulates the ovary. When estrogen reaches a critical peak, the pituitary releases a surge of LH (the LH spike) that releases an egg from the follicle.

  • Luteinizing hormone (LH) Surge

    The mid-cycle release of LH that causes an egg to be ovulated. Ovulation detection kits detect the sudden increase in LH signaling that ovulation is about to occur, usually within 24-36 hours.


  • Male factor

    Any cause of infertility due to low sperm count or problems with sperm function that make it difficult for a sperm to fertilize an egg under normal conditions.

  • Miscarriage (also called spontaneous abortion)

    A pregnancy ending in the spontaneous loss of the embryo or fetus before 20 weeks of gestation.

  • Morula

    A stage of embryo development after 4 days of culture in vivo (inside the body). Between the 8-cell stage and the blastocyst stage of development, all the cells of the embryo merge together, this is referred to as a morula.

  • Motility (of sperm)

    The ability of sperm to move and swim normally.

  • Multi-fetal pregnancy reduction

    A procedure used to decrease the number of fetuses a woman carries and improve the chances that the remaining fetuses will develop into healthy infants. Multi-fetal reductions that occur naturally are referred to as spontaneous reductions.

  • Multiple-infant birth

    A pregnancy that results in the birth of more than one infant.

  • Multiple-fetus pregnancy

    A pregnancy with two or more fetuses.


  • No Terms available


  • Oocyte

    The female reproductive cell, also called an egg.

  • Ovarian Cyst

    A persistent fluid-filled sac inside the ovary. Cysts can produce hormones that interfere with ART cycles.

  • Ovarian Hyper Stimulation Syndrome (OHSS)

    A potentially life-threatening condition following ovulation induction treatment. OHSS arises when too many follicles develop and hCG is given to release the eggs. This condition may be prevented by withholding hCG when ultrasound monitoring indicates that there are a large number of follicles in the ovaries. IF OHSS is evident during an IVF cycle, all the embryos may be frozen at the pro nuclear stage (the day after the egg collection) and replaced at a later date when the condition has subsided as pregnancy can exacerbate the symptoms of OHSS.

  • Ovarian monitoring

    The use of ultrasound and/or blood or urine tests to monitor follicle development and hormone production.

  • Ovarian stimulation

    The use of drugs (oral or injected) to stimulate the ovaries to develop follicles and eggs.

  • Ovulation

    The release of an egg from an ovarian follicle.

  • Ovulatory dysfunction

    A cause of infertility due to problems with egg production by the ovaries.

  • Ovum

    Another name for the egg.


  • Patent

    The condition of being open or unblocked (as with the fallopian tubes).

  • Pelvic Inflammatory Disease (PID)

    An infection of the pelvic organs that may lead to tubal blockage and pelvic adhesions.

  • Pituitary gland

    The mater gland. The pituitary gland is situated in the brain by the hypothalamus and controls all hormonal functions, including the gonads, the adrenal glands and the thyroid gland.

  • Polar body

    The discarded genetic material resulting from female germ cell division. When an egg matures it discards half of its genetic material so that the egg cell is ready to fuse with half the male genes inside a sperm. This discarded genetic material can be seen in the egg as a small round piece of cytoplasm at the edge of the egg cell. The presence of a polar body tells us whether an egg is mature or immature.

  • Polycystic ovaries

    A condition found in women who don't ovulate, characterized by excessive production of male sex hormones (androgens) and the presence of cysts on the ovary. PCO can be without symptoms although some women who do show symptoms are said to have PCOS.

  • Polycystic Ovary Syndrome (PCOS)

    A condition where the symptoms of having polycystic ovaries are evident. PCOS symptoms may include weight gain, acne and excessive hair growth.

  • Pregnancy (biochemical)

    A positive pregnancy test that shows no evidence of a gestational sac or viable fetus on ultrasound. Can be classified as a very early miscarriage.

  • Pregnancy (clinical)

    A pregnancy documented by ultrasound that shows a gestational sac containing a viable fetus in the uterus. For ART data collection purposes, pregnancy is defined as a clinical pregnancy rather than a biochemical pregnancy (i.e., a positive pregnancy test).

  • Progesterone

    The hormone produced by the corpus luteum after ovulation that supports the development and maintenance of the uterine lining.

  • Pro nuclear Stage (2PN)

    A fertilized egg (zygote). In IVF, the pro nuclear stage is the morning after the egg collection.

  • Pronuclei (PN)

    The evidence of fertilization. In a normally fertilized egg, two spherical structures (pronuclei) can be seen in the middle of the egg 16-22 hours post insemination. One of the spheres contains the female genetic material and the other contains the male genetic material before they fuse to form the genes of the embryo.


  • No Terms Available



    A national, nonprofit consumer organization offering education, advocacy, and support to those experiencing infertility.

  • Retrograde ejaculation

    A male infertility problem in which sperm travel into the bladder instead of out of the penis. This is due to a failure in the sphincter muscle at the base of the bladder. Medical intervention is necessary in order to conceive.


  • Salpingectomy

    Surgical removal of the fallopian tubes.

  • Semen

    The fluid portion of the ejaculate consisting of secretions from the seminal vesicles and prostate gland, and several other glands in the male reproductive tract.

  • Semen analysis

    A laboratory test to assess semen quality. Semen analysis includes, sperm count, morphology, motility, semen viscosity and volume.

  • Semen viscosity

    The liquid flow or consistency of the semen.

  • Society for Assisted Reproductive Technology (SART)

    An affiliate of the American Society for Reproductive Medicine composed of clinics and programs that provide ART. SART reports annual fertility clinic data to the CDC.

  • Sperm

    The male reproductive cell.

  • Sperm agglutination

    Sperm clumping caused by antibodies or by infection.

  • Sperm antibodies

    Antibodies that are made against sperm.

  • Sperm count

    The number of sperm in the ejaculate.

  • Sperm morphology

    The number or percentage of sperm which look microscopically normal.

  • Sperm motility

    The ability of sperm to move and swim normally.

  • Superovulation

    The stimulation of multiple ovulation with fertility drugs.

  • Stillbirth

    The birth of an infant with no signs of life after 20 or more weeks of gestation.

  • Stimulated cycle

    An ART cycle in which a women receives oral or injected fertility drugs to stimulate her ovaries to produce more follicles.


  • TESA

    Testicular Sperm Aspiration.

  • Testes

    The male reproductive gland; source of sperm and male sex hormones normally occurring paired in an external scrotal sac.

  • Testicular biopsy

    A minor surgical procedure used to take a small sample of testicular tissue for microscopic examination. Sperm may be retrieved using a testicular biopsy when there is a tubal blockage which is preventing sperm from being ejaculated.

  • Testosterone

    The male hormone.

  • Tubal factor infertility

    Structural or functional damage to one or both fallopian tubes that reduces fertility.


  • Ultrasound

    A technique used in ART for visualizing the follicles in the ovaries, the gestational sac, or the fetus.

  • Umbilical Cord

    Two arteries and one vein encased in a gelatinous tube leading from the baby to the placenta. The umbilical cord is used to exchange nutrients and waste between the mother and the developing baby.

  • Un-descended testes (Cryptorchidism)

    The failure of the testes to descend from the abdominal cavity by one year of age. If this condition is not treated promptly, sperm counts may be reduced in later life.

  • Unexplained infertility

    Infertility for which no cause has been determined despite a comprehensive evaluation of both partners.

  • Unstimulated cycle

    An ART cycle in which the woman does not receive drugs to stimulate her ovaries to produce more follicles. Instead, follicles develop naturally. She may produce only one or two follicles.

  • Urologist

    A physician specializing in the genitourinary tract.

  • Uterine factor

    A disorder in the uterus (e.g.,fibroid tumors) that reduces fertility.

  • Uterus

    The hollow muscular organ in which a fetus develops during pregnancy.


  • Vagina

    The canal leading from the cervix to the outside of a woman's body.

  • Varicocele

    A dilation of veins that carry blood out of the scrotum which leads to elevated scrotal temperature. A major cause of male infertility.

  • Vas Deferens

    The tubes through which sperm move from the testicles (epidermis) towards the seminal vesicles and prostate gland. These tubes are closed during a vasectomy.

  • Vasectomy

    A surgical procedure to block sperm from being released in the ejaculate. Vasectomy is used as a form of birth control.


  • No Terms Available


  • X Chromosome

    The female chromosome. Females have two X chromosomes in their genotype.


  • Y Chromosome

    The Male chromosome Males have one Y and one X chromosome in their genotype.


  • Zona Pellucida

    The outer ‘shell' surrounding the egg. The Zona Pellucida serves two purposes; firstly allowing only one sperm to enter the egg for fertilization and secondly to hold the cells of the developing embryo together before compaction.

  • Zygote

    A fertilized egg which has not yet divided.