Linea nigra - The line running from the navel to the pubic hair that can darken during pregnancy.

Latent labor - This first and longest phase of labor includes the early part of the effacement and dilation of the cervix and effacement.

Lightening (dropping) - Late in pregnancy, a feeling of lessened pressure on the upper abdomen as the fetus moves down into the pelvis. Once a baby "drops," it becomes easier for the mother-to-be to breathe, but pressure on her bladder is increased.

Lochia - Vaginal discharge in which excess uterine tissue is expelled after delivery. This bleeding can last two to four weeks after birth.

Low birth weight - A baby born weighing less than 5 pounds, 8 ounces.

Labor - Labor begins when prostaglandin hormones start to soften the cervix and the natural hormone oxytocin causes contractions that dilate the cervix. Signs that preceed labor can include persistent diarrhea, bloody show, and spontaneous rupture of the amniotic sac.

Lactation consultant - A health care provider specializing in breastfeeding, education, and support.

Lamaze method - A childbirth method intended to prevent or lessen labor pain through breathing techniques and through concentration on distracting stimuli, such as staring at a focal point.

Lanugo - The fine, downy hair covering a baby's body in the latter stages of gestation. Sometimes present at birth, lanugo often appears on a baby's shoulders and back. It will shed within one or two weeks.