Abortion: The termination of a pregnancy through the expulsion of the fetus from the uterus.
Abortion, spontaneous: Miscarriage that has not been induced artificially.
Alpha fetoprotein: A substance produced by the fetus. High levels in a mother's blood can indicate a neural tube defect or multiple pregnancy.
Amino acid: A building block of protein which is used by the body to build muscle and other tissue.
Amniocentesis: A prenatal test in which a small amount of amniotic fluid is removed for analysis.
Amniotic fluid: The fluid that surrounds a developing fetus.
Amniotic sac: The bag in which the fetus and amniotic fluid are contained during pregnancy.
Anencephaly: A severe congenital defect in which the fetus has no brain.
Anesthesia: Medically induced loss of sensation. General anesthesia involves the entire body; local anesthesia involves only a particular area.
Anomaly: Malformation or abnormality of a body part.
Antibiotic: A drug used to combat infection.
Antibody: A protein produced by the immune system to destroy foreign substances.
Apgar scoring system: A method of evaluating a baby's health immediately after birth.
Apnea: A temporary involuntary cessation of breathing.
Areola: The pink or brown area of skin around the nipple of the breast.
Aspirate: To inhale liquid into the lungs, or to remove liquid from the lungs with a suction device.