When you're not pregnant, the hairs on your head grow in a regular cycle. Each hair:

• Usually grows about one-half inch per month for anywhere from two to six years
• Then goes into a “resting” phase for 2 or 3 months
• Then gradually falls out, usually when you're brushing or washing your hair

The growth cycle then starts again. At any one time, about 10 percent of the hair on your scalp is in a resting phase, and about 90 percent is growing.

During pregnancy, hairs tend to stay in the resting phase longer. And much more of your hair is in the resting phase at any one time. Therefore, fewer hairs fall out each day. This causes your hair to seem thicker and fuller.

After delivery, this resting phase shortens. More hairs fall out, and you start to grow new hair. But the normal hair loss that was delayed by pregnancy tends to take place all at one time. This may cause your hair to seem thinner than usual.

Other hair growth. Some women also develop more hair on their chin, upper lip, cheeks, arms and legs during pregnancy. You also may notice new hairs (sometimes even just one or two) on your breasts, belly and back.

Pregnancy hormones and increased cortisone cause this type of hair growth during pregnancy. This growth usually lessens within about six months after pregnancy.

Hair Changes: What You Can Do
Hair growth on the face, arms and legs during pregnancy is normal. Your hair growth should return to its regular cycle within six months after delivery.

To get rid of unwanted hair growth, you can safely tweeze, wax or shave. Avoid using bleaches or depilatories that can be absorbed into the skin. Permanent hair-removal techniques (such as electrolysis) are thought to be safe during pregnancy. But they can be painful or uncomfortable.

You can do several things to have a healthier head of hair during pregnancy and after delivery:

• Eat a diet high in fruits and vegetables. These may provide protection for the hair shafts and encourage hair growth.
• Be gentle with your hair when it is fragile and wet. Avoid fine-tooth combs.
• Avoid using blow dryers and other heated hair instruments. If you must use a hair dryer, use the cooler settings.
• Avoid pigtails, cornrows, tight braids and tight hair rollers. They can pull and stress your hairs.

When to Talk to Your Health Care Provider

Some hair thinning in the months after delivery is normal. Your hair should return to its normal growing cycle without any special treatment. This hair thinning is usually not serious enough to cause bald spots or permanent hair loss.

If you have a lot of hair loss or lose quarter-size patches of hair, you may not be getting enough vitamins or minerals. It may also be a sign of a medical problem unrelated to your pregnancy (such as a skin disease or a thyroid disorder). Talk to your health care provider if you feel that your hair loss is unusual or excessive.