Oligohydraminos		A thin-walled hollow structure in early embryonic development that contains a cluster of cells called the inner cell mass from which the embryo arises.
Prostaglandin		Decreased amount of amniotic fluid, which may indicate fetal urinary tract defect.
Progesterone		A hormone synthesized by the syncytiotrophoblast that functions as an insulin antagonist and promotes lipolysis to increas the amounts of circulating free fatty acids available for maternal metabolic use
Estrogen		One of a number of hormone-like substances that participate in a wide range of body functions such as the contraction and relaxation of smooth muscle.
Intervillous Space		Developmental stage of the fertilized ovum in which there is a solid mass of cells.
Meiosis		A thin membrane surrounding the fetus during pregnancy. It's the inner of the two fetal membranes and contains the amniotic fluid.
Conception		The outermost of the two fetal membranes which surrounds the embryo and develops villi to give rise to the placenta.
Endometrium		A fork-shaped structure, specifically the fold of skin where the labia minora meets above the perineum.
Zygote		The space between the vessels of the mother and the embryo.
Teratogen		The union of male spermand female ovum; fertilization
Wharton's Jelly		Implantation of a fertilized ovum in the endometrium.
Trophoblast		The cell formed by the union of a sperm and an ovum, which develops into the embryo.
Blastocyst		One of the rounded portions into which the placenta's uterine surface is divided.
Luteinizing Hormone		A female hormone that is made mainly by the corpus luteum in the ovary and by the placenta. It prepares the endometrium of the uterus to receive and sustain the fertilized egg.
Nidation		Process of cell division whereby both daughter cells have the same number and pattern of chromosomes as the original cell.
Chorion		Hormone produced by the anterior pituitary during the first half of the menstrual cycle, stimulating development fo the graafian follicle.
Decidua		Endometrium or mucous membrane lining of the uterus in pregnancy that is shed after childbirth.
Follicle-Stimulating Hormone		A gelatinous substance within the umbilical cord and is a rich source of stem cells.
Human Choronic Gonadotropin		The process of cell division that occurs in the maturation of sperm adn ova that decreases their number of chromosomes by half.
Human Placental Lactogen		A hormone produced by the chorionic villi and found in the urine of pregnant women.
Morula		The inner lining of the uterus.
Amnion		A female hormone produced by the ovaries. Deficiencies can lead to osteoporosis.
Mitosis		Any agent that can disturb the development of an embryo or fetus.
Cotyledon		The outer layer of teh blastoderm that will eventually establish the nutrient relationship with the uterine endometrium.
Fourchette		Hormone responsible for stimulation ovulation and development of the corpus luteum.