marasmus
A severe case of malnutrition.
mastitis
An infection of a milk duct in the breast, most commonly between 10 and 28 days after delivery. Symptoms include swelling, tenderness, redness, and fever; treated with antibiotics.
meconium
A newborn's first bowel movements, which are dark, sticky, and usually greenish-black, and last for the first few days of the infant's life. If meconium is visible in the amniotic fluid prior to delivery, it can be a sign that the fetus is in distress.
membranes
Also know as the bag of waters, this thin sac contains the amniotic fluid and the fetus. The membranes will either rupture spontaneously during labor or be ruptured to speed up labor.
metatarsus valgus
Commonly known as a "duck walk." Generally corrects itself.
metatarsus varus
Commonly known as "pigeon toed." Generally corrects itself but may need surgery in severe cases.
microcephaly
A small skull with small cranial capacity. Usually indicates mental retardation.
micromelia
A birth defect in which arms or legs are abnormally short.
milia
Tiny pimples on a newborn's face, usually around the nose or chin, and also sometimes on a baby's torso, arms, and legs. Caused by clogged pores, milia will disappear on their own, usually within a few weeks.
miscarriage
The involuntary loss of a pregnancy before 20 weeks, estimated to end 15 to 20 percent of all pregnancies. More than 80 percent of miscarriages occur in the first 12 weeks of pregnancy, many before a woman even knows she's pregnant.
Mongolian spot
Large bluish birthmarks, usually on the lower back or buttocks, more common in darker skinned babies. Usually fade or disappear as a baby grows.
Moro reflex
The automatic response to loud noises or sudden movements in which a newborn will extend his arms and legs, arch his back, and sometimes cry out. Newborns can have this reaction even during sleep, but lose it after a few months.
mucus plug
A collection of mucus, often tinged with blood, that blocks the cervix during pregnancy; known as the "bloody show" when discharged prior to labor. The texture and amount of mucus discharged varies greatly from woman to woman.
