Diminishing estrogen levels can potentially influence almost every bodily system, including hair production. As such, the appearance of thinning hair is often associated with menopause. It is important to note that the physical and mental indications of declining hormone levels, such as thinning hair, can occur before menstrual periods have ended.

This period of declining hormones is called the climacteric or perimenopause. Perimenopause can last several years and often includes many of the characteristic symptoms of menopause.

Pregnancy & Nursing

When a woman is pregnant, the amount of estrogen and another hormone, progesterone... is dramatically affected to create the proper environment for the developing child and to prepare the mother for nursing. While the primary role of these hormones is to support the baby, they also affect other bodily functions.

Since thinning hair, hair loss and hair texture are linked to hormone levels, a woman may experience excessive daily hair loss or a change in hair texture during pregnancy and nursing. In most cases, this is usually a normal, temporary condition. Her normal hair-growth-and-loss sequence should regain its proper balance after about six months.

Oral Contraceptives

Since the pill alters the amount of estrogen's in the body (either in the form of estrogen or progestin). And a woman who begins or stops taking oral contraceptives may experience temporary shedding that can continue for up to six months. In addition there are other common drugs that can cause hair loss