Four-month-old babies may using crying to demonstrate when they need something. They are able to recognize signs of hunger, discomfort, such as bored or wet diapers, or when they are sleepy.

By 18 months a baby should have developed the ability to walk alone, including standing up, balancing, and taking steps. Babies who cannot walk by 18 months should be evaluated by their physician.

Extra-uterine growth is affected by the patient's monthly hormonal cycle. The resulting bleeding does not have an exit route.

Functional hypothalamic amenorrhea (FHA) relates to excessive physical or emotional stress that results in amenorrhea (absent periods).

POI is a condition in which a woman's ovaries stop producing hormones and producing eggs at a young age.

NuvaRing is a small, flexible vaginal ring which you put in for 3 weeks, take it out, then put a new one in a week later.