Common OB/GYN Terms

Antepartum - Before birth. Also called prenatal.

Amniotic Sac or "Bag of Waters" - The thin membrane that encloses the baby and the amniotic fluid. At full term, there is roughly a quart of amniotic fluid surrounding the baby. About one third of this fluid is constantly being replenished every hour.

Bladder - The body organ that holds urine. It is located between the pubic bone and the uterus. Because of the size of the uterus during pregnancy, the bladder cannot store much urine and has to be emptied frequently. The urethra is the bladder opening.

Braxton-Hicks Contractions - Usually painless uterine contractions present from the earliest days of pregnancy which the mother may feel from about the fifth month on. These contractions help to enlarge the uterus. They may occur more frequently and become greater in intensity as the mother gets closer to the start of true labor.

Breech - One or both feet or buttocks first - occurs in 3.5 percent of births.

C-Section - Cesarean section, delivery of the baby through an incision in the abdomen.

Cephalic or vertex - Head first - occurs in more than 95 percent of births.

Cervix - The neck or mouth of the uterus (womb). This is the part of the uterus that stretches or opens for the birth of the baby.

Contractions - The rhythmic tightening and relaxation of the uterine muscles, which results in the effacement and dilation of the cervix and the eventual delivery of the baby. True labor contractions usually come in a regular pattern, gradually get closer together, and gradually increase in intensity. The frequency of the contractions is measured from the beginning of one contraction to the beginning of the next contraction; the duration refers to length of one contraction; and the intensity refers to the strength of the contractions.

Dilation - The opening up of the cervix so that the baby can pass from the uterus to the vagina or birth canal. Measured in centimeters from 0 to 10.

EDC - Expected date of confinement; your estimated date of delivery or due date.

Effacement - The thinning and shortening of the cervix. In the primigravida, effacement is usually complete before the cervix begins to open up. Measured in percentages from 0 to 100.

Engagement - The entrance of the baby's presenting part into the upper oval of the mother's pelvis. In primigravida, engagement often takes place about two weeks before the baby's birth. In experienced mothers, it can occur as late as the onset of labor.

Episiotomy - A small surgical incision of the perineum made to enlarge the vaginal opening. If an episiotomy is necessary, it is done just before the birth of the baby.

FHT - Fetal heart tones (the baby's heart beat). The normal range is 110 to 160 Beats per minute.

Fundus - The top or uppermost portion of the uterus.

Labor - The physiological process by which the fetus is delivered from the uterus.

Lightening - The sensation the mother feels when the baby "drops" down or gradually settles into the pelvis as the presenting part becomes engaged.

Membranes - A thick, protective sheath that holds fluid around the baby.

Multigravida - A woman pregnant with her second or subsequent child.

Multipara - A woman who has given birth to more than one child.

Perineum - The external tissues surrounding the urethra, vagina, and anus; the space between the vagina and anus. The elasticity of these tissues varies with the individual and has a bearing on whether or not an episiotomy needs to be done.

Placenta - An organ which supplies nourishment to the baby during the pregnancy. Also called "afterbirth".

Postpartum - After the birth.

Presentation - Refers to the part of the baby which can first be felt through the cervix upon vaginal exam; the part of the baby which will first enter the birth canal.

Primigravida - A woman pregnant with her first child.

Shoulder (transverse lie) - Baby laying on its side the uterus - occurs in less than 1.5 percent of births.

Station - The location of the baby's head in relation to the bones of the mother's pelvis. "Minus" numbers indicate that the baby has not started moving down into the pelvis; "plus" numbers indicate that the baby's moving down into the pelvis.

Uterus - The muscular organ of the body that holds the baby. It weighs about 2 ounces in a non-pregnant woman. Just before birth, it may weigh up to 2 pounds. Also called the womb.

Vagina - The birth canal.

Vulva - The "lips" around the opening of the vagina.