Pregnancy affects the entire body, including hair, skin and nails. So Hair loss during and after pregnancy can be due to hormonal problems. An overactive or under active thyroid can cause hair to fall out. If this is the case, your physician can treat the hair loss by treating the hormone imbalance.  Hormonal changes that cause hair loss during pregnancy will often resolve themselves as the body returns to pre-pregnancy hormone levels and the normal cycle of hair growth and loss starts again. Hair loss during pregnancy may also be a sign of a vitamin or mineral deficiency. Hair loss is especially common just after pregnancy.

Causes

A number of things can cause excessive hair loss. For example, about 3 or 4 months after an illness or a major surgery, you may suddenly lose a large amount of hair. This hair loss is related to the stress of the illness and is temporary.

Hormonal Problems may cause hair loss. If your thyroid gland is overactive or under active, your hair may fall out. This hair loss usually can be helped by treatment thyroid disease. Hair loss may occur if male or female hormones, known as androgens and estrogens, are out of balance. Correcting the hormone imbalance may stop your hair loss.

Some Medicines can cause hair loss. This type of hair loss improves when you stop taking the medicine. Medicines that can cause hair loss include blood thinners (also called anticoagulants), medicines used for gout, medicines used in chemotherapy to treat cancer, vitamin A (if too much is taken), birth control pills and antidepressants.

Stress is another factor linked to hair loss. While it has not been proved definitively, emotional trauma has been loosely associated with hair loss, but milder strains and worries probably do the same thing. Stresses placed on the body may also cause a woman’s hair to jump ship. For example, crash dieting, in which a woman loses a large amount of weight rapidly, may also cause her to lose her tresses, too. Since stress is often transient, if its cause clears up, the resultant hair loss should disappear as well.