Amniocentesis: A procedure in which amniotic fluid and cells are taken from the uterus for testing. The procedure uses a needle to withdraw fluid and cells from the sac that holds the fetus.
Amnionicity: The number of amniotic (inner) membranes that surround fetuses in a multiple pregnancy. When multiple fetuses have only one amnion, they share an amniotic sac.
Amniotic Sac: Fluid-filled sac in a woman’s uterus. The fetus develops in this sac.
Birth Defects: Physical problems that are present at birth.
Cerebral Palsy: A disorder of the nervous system that affects movement, posture, and coordination. This disorder is present at birth.
Cesarean Birth: Birth of a fetus from the uterus through an incision made in the woman’s abdomen.
Chorion: The outer membrane that surrounds the fetus.
Chorionic Villus Sampling (CVS): A procedure in which a small sample of cells is taken from the placenta and tested.
Chorionicity: The number of chorionic (outer) membranes that surround the fetuses in a multiple pregnancy.
Complication: A disease or condition that happens as a result of another disease or condition. An example is pneumonia that occurs as a result of the flu. A complication also can occur as a result of a condition, such as pregnancy. An example of a pregnancy complication is preterm labor.
Diabetes Mellitus: A condition in which the levels of sugar in the blood are too high.
Diagnostic Tests: Tests that look for a disease or cause of a disease.
Discordant: A large difference in the size of fetuses in a multiple pregnancy.
Eclampsia: Seizures occurring in pregnancy or after pregnancy that are linked to high blood pressure.
Egg: The female reproductive cell made in and released from the ovaries. Also called the ovum.
Embryo: The stage of development that starts at fertilization (joining of an egg and sperm) and lasts up to 8 weeks.
Fetus: The stage of human development beyond 8 completed weeks after fertilization.
Fraternal Twins: Twins that have developed from two different fertilized eggs.
Genetic Disorders: Disorders caused by a change in genes or chromosomes.
Gestational Diabetes: Diabetes that starts during pregnancy.
Identical Twins: Twins that have developed from a single fertilized egg that are usually genetically identical.
In Vitro Fertilization (IVF): A procedure in which an egg is removed from a woman’s ovary, fertilized in a laboratory with the man’s sperm, and then transferred to the woman’s uterus to achieve a pregnancy.
Menstrual Cycle: The monthly process of changes that occur to prepare a woman’s body for possible pregnancy. A menstrual cycle is defined as the first day of menstrual bleeding of one cycle to the first day of menstrual bleeding of the next cycle.
Multiple Pregnancy: A pregnancy where there are two or more fetuses.
Obstetrician–Gynecologist (Ob-Gyn): A doctor with special training and education in women’s health.
Ovaries: Organs in women that contain the eggs necessary to get pregnant and make important hormones, such as estrogen, progesterone, and testosterone.
Ovulation: The time when an ovary releases an egg.
Placenta: An organ that provides nutrients to and takes waste away from the fetus.
Postpartum Depression: A type of depressive mood disorder that develops in the first year after the birth of a child. This type of depression can affect a woman’s ability to take care of her child.
Preeclampsia: A disorder that can occur during pregnancy or after childbirth in which there is high blood pressure and other signs of organ injury. These signs include an abnormal amount of protein in the urine, a low number of platelets, abnormal kidney or liver function, pain over the upper abdomen, fluid in the lungs, or a severe headache or changes in vision.
Prenatal Care: A program of care for a pregnant woman before the birth of her baby.
Preterm: Less than 37 weeks of pregnancy.
Screening Tests: Tests that look for possible signs of disease in people who do not have signs or symptoms.
Sperm: A cell made in the male testicles that can fertilize a female egg.
Twin–Twin Transfusion Syndrome (TTTS): A condition of identical twins in which one twin gets more blood than the other during pregnancy.
Ultrasound Exam: A test in which sound waves are used to examine inner parts of the body. During pregnancy, ultrasound can be used to check the fetus.
Umbilical Cord: A cord-like structure containing blood vessels. It connects the fetus to the placenta.
Uterus: A muscular organ in the female pelvis. During pregnancy, this organ holds and nourishes the fetus. Also called the womb.