Infertility Terms & Definitions
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): A surgical procedure where small incisions are made in the abdomen and in the navel, where a fiber optic scope is inserted to examine and repair any of the pelvic organs.
Laparotomy: Major abdominal surgery where reproductive organ abnormalities can be corrected and fertility restored, such as tubal repairs and the removal of adhesions.
Leiomyoma: (Fibroid or Myoma). A non-cancerous, benign tumor of the uterine muscle and connective tissue.
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.
Leukocytosis: Increase in the number of Leukocytes (White Blood Corpusles) generally caused by infection and usually transient.
Leydig Cell: The testicular cell that produces the male hormone testosterone. The Leydig cell is stimulated by LH from the pituitary gland.
LH Surge: See Lutenizing Hormone Surge.
LIT: See Leukocyte Immunization Therapy.
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 and pre-menstrual phase of a woman's cycle lasting approximately ten to sixteen days. During this phase 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 properly 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 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.
