Glossary of Common Fertility Terms
Assisted Reproductive Technology (ART) – Treatments and procedures involving the handling of human eggs and sperm for the purpose of establishing a pregnancy. Types of ART include in vitro fertilization (IVF), oocyte donation, preimplantation genetic diagnosis (PGD) intracytoplasmic sperm injection (ICSI), assisted hatching, fragment removal, embryo cryopreservation, frozen embryo transfer and oocyte donation.
Blastocyst – An embryo that is approximately five days old and consists of some 100 cells that form an outer layer surrounding a fluid core. The outer cells develop into the placenta, which protects the fetus created from the inner cells. Blastocysts are used in five-day in vitro fertilization transfers, typically allowing for the replacement of two embryos instead of three or four. This larger number is customary when embryos are transferred on the third day of development.
Corpus Luteum – After a woman ovulates, the fluid filled sac in which the egg matures (the follicle) becomes the corpus luteum. It continues to produce androgen, estrogen and progesterone, hormones that prepare the uterine lining to accept and nurture the fertilized egg.
Culture Systems – In most cases of in vitro fertilization, eggs and sperm are united in a laboratory dish. The solution, or medium, is a solution of salts and nutrients that replicate conditions within the female body. In other cases, embryos may grow on a layer of cells from humans or cows. These “helper cells” provide nutrients and remove harmful compounds from the vicinity of the developing embryos.
Cytoplasmic Transfer – A laboratory-based micromanipulation technique that involves the injection of the cytoplasm from a healthy egg from a donor into the core of another woman’s egg. The intent is to overcome deficiencies that preclude normal development of embryos created after the deficient egg is fertilized.
Fluorescence In-situ Hybridization (FISH) – A laboratory technique, used in preimplantation genetic diagnosis, to distinguish abnormal cells taken from a human embryo. FISH uses probes – small pieces of DNA that are “labeled” with a fluorescent dye. When applied to the cell being studied, the probes attach to matching chromosomes, showing the geneticist whether the cell has an unbalanced make-up, indicating a genetic abnormality. Embryos with certain identifiable chromosomal abnormalities that may prevent implantation, contribute to pregnancy loss or result in a child born with a genetic disease are not transferred into the female during in vitro fertilization.
Fragment Removal – Performed in conjunction with assisted hatching, this laboratory-based technique involves removal of tiny pieces of cytoplasm from between the individual cells of an embryo to help it develop normally.
Geneticist – A specialist in the areas of biology that deal with genetic make-up and heredity. Geneticists in the field of human reproductive medicine focus on eggs and sperm, as well as the embryos and offspring resulting from fertilization.
Human Chorionic Gonadotropin (HCG) – A hormone produced following ovulation, it aids the corpus luteum in production of progesterone, required to prepare the uterine lining for implantation of the fertilized egg.
Hydrosalpinges – A condition caused by infection and a severe blockage of the female’s fallopian tubes by a hydrosalpinx. This mass can cause a build up and overflow of fluid into the uterus, where it is toxic to developing embryos.
Hypothalmic Amenorrhea – This results when the hypothalamus, a gland in the brain, stops producing gonadotropin-releasing hormone (GnRH), which stimulates the pituitary gland to release the appropriate levels of follicle-stimulating hormone (FSH and luteinizing hormone (LH) needed for egg development and ovulation.
Hysteroscopy – An outpatient diagnostic procedure in which the physician uses a fiber optic scope, inserted through the vagina and cervical canal, to examination of the inside of the uterus. If adhesions or blockages exist, they often can be removed during the same procedure.
Intracytoplasmic Sperm Injection (ICSI) – A micromanipulation procedure, ICSI is used most commonly in cases of severe male infertility. It involves injection of a single sperm directly into the core of an egg.
In Vitro Fertilization (IVF) – An assisted reproductive technology, IVF involves combining an egg and sperm in a laboratory dish to facilitate fertilization. If fertilization occurs, a limited number of resulting embryos are transferred to the uterus.
Laparoscopy – This outpatient procedure allows a physician to view the ovaries, as well as the outside of the fallopian tubes and uterus, with a scope inserted through a small incision below the woman’s navel. If necessary, growths and blockages may be removed during the same procedure.
Laparotomy – Major surgery performed on an inpatient basis, it allows for the examination of the pelvic area and removal of growths, scar tissue or other obstructions affecting the reproductive organs.
Luteinizing Hormone (LH) – The increase in LH (produced by the pituitary gland) during the middle of a woman’s cycle triggers ovulation, the release of a ripened egg from a follicle. In the male, LH contributes to development of reproductive tissue.
Micromanipulation – The mechanical manipulation of oocytes, sperm or embryos under a microscope. Intracytoplasmic sperm injection (ICSI), assisted hatching and embryo biopsy are all forms of micromanipulation.
Microsurgical Sperm Aspiration – Procedures using an operating microscope to obtain sperm that can be used in conjunction with Intracytoplasmic Sperm Injection (ICSI) in certain cases of male infertility.
Microsurgical Epididymal Sperm Aspiration (MESA) – A microsurgical procedure to extract fluid and sperm directly from an epididymal tubule, where sperm is stored. The sperm is prepared in the laboratory for use with ICSI.
Ovulatory Dysfunction – Any one of a number of conditions that affect menstruation and ovulation. Ovulatory dysfunction results from congenital defects, hormonal deficiencies and/or the aging process. Types include amenorrhea, lack of a period; anovulation, when no eggs are released during ovulation; oligo-ovulation, characterized by longer cycles and infrequent ovulation and luteal phase defects, other types of ovulatory dysfunction.
Polar Body – Two microscopic structures that are produced by the ripening egg and degenerate after fertilization. Examination of the polar bodies provides an indication of the egg’s chromosomal content.
Polycystic Ovarian Syndrome (PCOS) – A genetically-linked hormonal imbalance that prevents ovulation. PCOS also may cause overproduction of estrogen, abnormal thickening of the uterine lining, very heavy and/or irregular periods, as well as acne and facial hair. The latter are caused by an overproduction of male hormones, including testosterone.
Preimplantation Genetic Diagnosis (PGD) – A technique that involves examination of the chromosomes contained in the polar body, taken from an egg, or a blastomere from a developing embryo. Using a special technique, scientists and geneticists look for genetic abnormalities that can affect embryo implantation, contribute to miscarriage or cause genetic disease in offspring.
Premature Ovarian Failure – Also called early menopause, this can result from exposure to certain chemicals, chemotherapy and radiation for cancer treatment. Other causes are certain genetic disorders and conditions that affect the cycle-regulating hormones or damage the ovaries so they no longer produce eggs.
Reproductive Endocrinologist – A gynecologist who has received board certification in reproductive endocrinology and infertility, following additional fellowship training in the causes, evaluation and treatment of infertility.
Single Sperm Freezing – This technique may be used in cases of severe male infertility, when sperm are collected through microsurgery and very few remain following in vitro fertilization. To facilitate the thawing and identification of sperm for a subsequent IVF cycle, a few are placed inside an empty zona pellucida (the outer membrane of a human or hamster egg) prior to cryopreservation.
Testicular Biopsy – A procedure that allows for microscopic examination of a tissue sample containing the semniferous tubules that contain sperm. The sample, removed through a small incision in the scrotum, can help determine the causes of infertility and suggest a course of treatment.
Testicular Sperm Extraction (TESE) – A procedure for extracting sperm by removing a small sample of testicular tissue through an incision in the testes. In the laboratory, the tissue is processed to extract sperm for use with intracytoplasmic sperm injection and in vitro fertilization.
Ultrasound – A diagnostic procedure that produces a two-dimensional picture used for the examination, evaluation and measurement of the abdominal cavity and reproductive organs, as well as the developing follicles. Saline sonograms are ultrasounds that use warm saline to expand the fallopian tubes for better visualization.
Varicocelectomy (Varicocele Repair) – Microsurgery performed to tie off swollen veins around the male testes. This prevents the pooling of blood that can raise testicular temperatures and potentially affect sperm production.
Vasovasostomy (Vasectomy Reversal) – Microsurgical removal of scarred sections, and recon-nection of the inner and outer layers of the vas deferens after a vasectomy, allowing sperm to travel out of the epididymis and into the ejaculate.
Vasoepididymostomy (Epididymal Repair) – A microsurgical technique used in cases where the epididymal tubule is blocked, it involves stitching both layers of the vas deferens directly to the epididymis and its inner tubule at a point above the obstruction, allowing fluids to bypass the blockage.