The International Council on Infertility Information Dissemination, Inc

LAD -- See Leukocyte Antibody Detection Assay.

Laparoscope -- A small telescope that can be inserted into a hole in the abdominal wall for viewing the internal organs; the instrument used to perform a laparoscopy. Used to diagnose and treat a number of fertility problems including endometriosis, abdominal adhesions, and polycystic ovaries. Also used in egg retrieval for in vitro fertilization. Examination of the pelvic region by using a laparoscope is called a laparoscopy.

Laparoscopy (LAP) -- Examination of the pelvic organs through use a small telescope called a laparascope.

Laparotomy -- Major abdominal surgery where reproductive organ abnormalities can be corrected and fertility restored, such as tubal repairs and the removal of adhesions.

Leukocytosis --- Increase in the number of Leukocytes (White Blood Corpusles) generally caused by infection and usually transient.

Leukocyte Antibody Detection Assay (LAD) -- Test indicates a woman's physiologic response to pregnancy. Women who test for high levels of leukocyte antibodies have a history of carrying pregnancies longer than women who exhibit low levels. Women who have low levels of leukocyte antibodies generally had pregnancies that ended by week 12, or their immune systems did not respond to the stimulus of pregnancy by creating blocking antibodies. Only women with low levels of LAD are candidates for immunization with their husbands' white blood cells (leukocytes), so it is recommended that this assay be done prior to initiating an immunization protocol.

Leukocyte Immunization Therapy (LIT) -- Injecting a woman with her husband's or a donor's white blood cells to increase her fetal blocking antibodies and lower her NK cells.

Leydig Cell -- The testicular cell that produces the male hormone testosterone. The Leydig cell is stimulated by LH from the pituitary gland.

LIT -- See Leukocyte Immunization Therapy.

Listeria are bacteria which can cause an infection known as listeriosis. The bacteria are very resistant to common food preservation agents such as heat, salt, nitrite, and acids. It can also multiply in refrigerated foods. Listeria is often present in the intestines of seemingly healthy animals. The bacteria can contaminate milk and meat products produced from infected animals and can also contaminate vegetables fertilized with contaminated manure. Since the early 1980s Listeria infections have been traced to food products such as coleslaw, milk, soft cheeses, hot dogs, and luncheon meats. Pregnant women are advised to avoid foods, such as soft cheeses, that are easily contaminated with Listeria. Taking precautions such as thoroughly cooking foods, eating only pasteurized milk products, washing fruits and vegetables, and washing hands after contact with raw meat also reduces the chances of contracting listeriosis. The federal government has established programs to test for Listeria in ready-to-eat foods and to recall food containing the bacteria. Healthy people are generally resistant to listeriosis but pregnant women are very susceptible to the infection. Listeria infections in pregnant women may result in miscarriages or stillbirths. Meningitis (brain infections) and septicemia (bacteria in the bloodstream) may occur in infants born to women with listeriosis.

Listeriosis: is a serious infection caused by eating food contaminated with the bacterium Listeria monocytogenes, has recently been recognized as an important public health problem in the United States. The disease affects primarily pregnant women, newborns, and adults with weakened immune systems. It can be avoided by following a few simple recommendations. Pregnant women are about 20 times more likely than other healthy adults to get listeriosis. About one-third of listeriosis cases happen during pregnancy.

Low Responder -- A woman who does not produce many follicle with injectable fertility medications.

Lupron -- An injectable medication used to down-regulate the pituitary gland and prevent the release of substances such as Luteinizing Hormone (LH) and Follicle Stimulating Hormone (FSH). Without LH or FSH, the ovary will not produce follicles that will in turn decrease the production of Estrogen and Progesterone.

Lupus -- See Systemic Lupus Erythematosus.

Lupus Anticoagulant -- An antibody causing elevation in partial thromboplastin time (the time needed for plasma to form a clot after the addition of calcium and a phospholipid reagent; used to evaluate the clotting system), associated with venous and arterial thrombosis (clotting within an artery or vein).

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

Luteal Phase Defect (or Deficiency) (LPD) -- A condition that occurs when the uterine lining does not develop adequately because of 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 miscarriage.

Luteinized Unruptured Follicle Syndrome (LUFS) -- A condition in which the follicle develops and changes into the corpus luteum without releasing the egg. This sometimes goes hand-in-hand with PCO. The use of non-steroidal anti-inflammatory drugs such as Advil, Motrin, and Aleve, near ovulation may also contribute to LUFS.

Luteinizing Hormone (LH) -- A pituitary hormone that stimulates the gonads. In the man LH is necessary for spermatogenesis (Sertoli cell function) and for the production of testosterone (Leydig cell function). In the woman LH is necessary for the production of estrogen. When estrogen reaches a critical peak, the pituitary releases a surge of LH (the LH spike), which releases the egg from the follicle.

Luteinizing Hormone Surge (LH Surge) -- The spiking release of luteinizing hormone (LH) that causes release of a mature egg from the follicle. Ovulation test kits detect the sudden increase of LH, signaling that ovulation is about to occur (usually within 24-36 hours).

Lymphocyte --- cell present in the blood and lymphatic tissue. Less than 1% are present in the circulating blood. These cells travel from the blood and lymph nodes and back into circulation. Lymphocytes are derived from the stem cells from which all blood cells arise.