Effacement - The thinning of the cervix.

Eclampsia - A severe, possibly life-threatening form of preeclampsia (toxemia), in which the expectant mother suffers from seizures or convulsions.

Ectopic pregnancy - A dangerous condition in which the fertilized egg implants outside the uterus, usually in the fallopian tubes.

Edema - Swelling, often in the face, fingers, ankles, and feet, as a result of fluid retention.

External cephalic version - A procedure in a which a doctor attempts, through pressure applied to a woman's abdomen, to turn the fetus from a breech position to a head down, or vertex presentation, for delivery.

Electronic fetal monitoring - A method in which electronic instruments -- placed internally or externally -- are used to record the fetus's heartbeat and contractions of the uterus.

Embryo - The early stage of development of a fertilized egg, lasting approximately eight weeks following ovulation.

Engorgement - The swelling of the glands in the breast that produce milk.

Epidural - A method of labor-pain relief in which medication is injected into the lower back to relieve pain from the waist down.

Episiotomy - The surgical incision made in the perineum to widen the vaginal opening for delivery of the baby's head.