What hair changes are common during pregnancy?

Hair changes in pregnancy are very common, and body hair changes are common as well. Many women develop mild hirsutism that may be due to levels of male hormone production by the ovary and adrenal gland.

In nonpregnant patients, hair grows in the anagen phase and rests in the telogen phase. About 15-20% of all hairs are in the telogen phase at any given time. During pregnancy, however, more scalp hairs are in the anagen phase, so more growth is documented. During the telogen resting phase, it is normal for hair to fall out so new hair can regrow. During late pregnancy, fewer hairs are in the telogen phase; immediately postpartum, more hairs are in the telogen phase. This often results in a dramatic loss of hair immediately postpartum; this is termed telogen effluvium. Although this may be disturbing, it is normal.

Normal hair loss is probably in the range of 60-100 hairs a day and most patients do not notice a dramatic loss unless 40% of all hair is lost. This process spontaneously resolves in about 1-5 months, but has been reported to last more than a year. The frontal and parietal areas are usually most affected. No effective treatment is known.