Causes of Hair Growth

Irregular menstrual cycles can cause excess hair growth due to hormone levels.

Unwanted hair growth—particularly on the face, chest, abdomen, or back—can be triggered by several hormonal conditions, all of which involve an imbalance in androgens (male hormones) in the female body.

Polycystic Ovary Syndrome (PCOS): This common hormonal disorder affects women of reproductive age and is characterized by elevated androgen levels, irregular periods, and often, multiple small cysts on the ovaries. The excess androgens stimulate hair follicles, leading to hirsutism, or the growth of coarse, dark hair in areas typically associated with male-pattern hair.

Ovarian Hyperthecosis: A more severe form of hormonal imbalance, hyperthecosis occurs when the ovaries produce excessive androgens due to the presence of hormone-producing cells in the ovarian tissue. It can cause intense, widespread hair growth, often more severe than in PCOS. This condition may also increase the risk of ovarian tumors or cancer, especially in postmenopausal women, making it important to diagnose and monitor closely.

Specific thyroid problems could cause unwanted hair.

Obesity can cause the development of a synthetic androgen hormone that causes excess hair growth.

Puberty, pregnancy, and menopause can also cause excess hair growth. During the regular systemic changes in a woman's life, hormone production varies. It is not uncommon for hormones during these times to be unbalanced. 

Increased male hormones called androgens can be present, which may result in unwanted hair growth.

Both pregnancy and menopause involve major hormonal shifts that can affect hair growth in unexpected ways, including the appearance of unwanted body or facial hair.

During Pregnancy: The body produces higher levels of estrogen and androgens to support the developing fetus. These hormonal changes can increase hair growth all over the body. Some women may notice new, darker hair appearing on the abdomen, face, chest, or back. This is usually temporary and tends to return to normal postpartum as hormone levels stabilize.

During Menopause: Estrogen levels drop significantly, while androgen levels decline more slowly. This creates a relative increase in androgens, which can stimulate the growth of coarse, dark hair in areas typically more common in men, such as the chin, upper lip, or chest. This condition is known as hirsutism and can persist or worsen with age.

In both stages, the imbalance or shift in estrogen and androgen levels is the key factor driving changes in hair patterns. While pregnancy-related hair growth often fades after childbirth, menopause-related hair growth may be more persistent and require ongoing management.