For women, a sudden loss of hair can be quite a shock. Before you hit the panic button, know there’s a good chance the hair loss, or alopecia, is temporary, if it’s related to your hormones. It can help to understand how your hair normally grows. Did you know only 90% of your hair grows at a time? The remaining 10% goes into a resting phase and falls out naturally within a few months to make room for new hair to grow. However, estrogen, progesterone, and thyroid hormones can disrupt this normal process. Estrogen, Pregnancy, and Your Hair Between 40% and 50% of women have excessive hair loss during pregnancy because the level of estrogen hormones is higher. The hair loss usually occurs within the first five months. Rest assured, it won’t lead to permanent bald spots. Not all women lose hair when they’re pregnant, however. Some women have the opposite experience. Their hair grows thicker and fuller than ever, and they love the new look. Excessive hair loss after delivery is even more common as estrogen hormones dip back to a normal level. Hair loss usually starts about three months after the baby is born and stops within six months to a year. A change in estrogen levels that leads to hair loss can be caused by factors other than pregnancy. These include stopping hormonal birth control, miscarriage, stillbirth, and abortion. Androgen, Menopause, and Hair Loss During menopause, the levels of the female hormones estrogen and progesterone fall, and the level of the male hormone androgen rises. This makes hair grow more slowly and shrinks hair follicles, which weakens hair. You may hear this type of hair loss referred to as “androgenetic alopecia.” The resulting hair loss is often temporary. After menopause, up to two-thirds of women continue to experience thinning hair or bald spots. If it bothers you, talk with your doctor. Effective hair loss medications are available for women, as well as hair transplantation procedures. Thyroid Problems While hair loss in women can be linked to life stages, it can also occur at more seemingly random times due to fluctuations in thyroid hormones. The same is true for men. Thyroid hormones are made by the thyroid gland. You may think of these hormones as controlling your metabolism, but they also control hair growth. If the thyroid gland doesn’t produce enough hormone, it’s known as hypothyroidism. If the gland produces too much hormone, it’s known as hyperthyroidism. You may also hear the respective terms “underactive thyroid” and “overactive thyroid.” One clue your hair loss may be related to your thyroid is the hair loss pattern. Thyroid-related hair loss affects the whole scalp rather than individual patches. You may also notice hair loss on other parts of your body, including your eyebrows. Hair loss caused by a thyroid problem is usually temporary. Hair starts growing normally over a period of several months as the underlying condition is treated. A thyroid condition is definitely not something you want to self-diagnose. And, while hair loss can be caused by hormones, it can also be caused by heredity or other factors. Talk with your doctor to get an appropriate diagnosis and explore appropriate treatment options.