amniotic sac - a thin-walled sac that surrounds the fetus during pregnancy. The sac is filled with amniotic fluid - liquid made by the fetus and the amnion (the membrane that covers the fetal side of the placenta) that protects the fetus from injury and helps to regulate the temperature of the fetus.

anesthesia - medications that cause loss of sensation; includes pudendal block, epidural anesthesia, spinal anesthesia, and general anesthesia.

Braxton Hicks contractions - relatively brief, painless contractions of the uterus that may begin during the second half of pregnancy.

colostrum - a fluid in the breasts that nourishes the baby until the breast milk becomes available. Colostrum contains fats, carbohydrates, white blood cells, protein, and antibodies.

edema - swelling due to the buildup of fluid.

episiotomy - an incision through the vaginal wall and the perineum (the area between the thighs, extending from the anus to the vaginal opening) to help deliver the fetus.

epidural anesthesia (Also called a epidural block.) - the infusion of numbing medications through a thin catheter that has been inserted into the space that surrounds the spinal cord in the lower back, causing loss of sensation of the lower body.

group B Streptococcus (GBS) - bacteria found in the genital tract of women that can cause serious illness in pregnancy and in the newborn.

preeclampsia - a condition characterized by pregnancy-induced high blood pressure, protein in the urine, and swelling (edema) due to fluid retention.