Birth Control and Weight Gain: Understanding the Connection

Birth-control contraceptives have been associated with weight gain. The hormone estrogen is the culprit. Estrogen reacts with the kidneys, allowing them to retain sodium and in turn hold excess water. Generally, weight gain is seen as a negative attribute, but for some weight gain is beneficial.

The Pill

• National Women's Health Resource Center defines the combination pill as containing both estrogen and progestin hormones. Pills high in estrogen levels, such as Yaz and Seasonique, can cause a change in eating habits that may contribute to weight gain.

The Shot

• Depo-Provera is the injected liquid and only consists of progesterone. Dr. Lois M. Jessen also sites progestin for fluid retention and the added production of androgen, which are male hormones that induce weight gain.

Fluid Retention

• Renin-angiotensin is a hormone responsible for regulating the body's blood pressure and water balance. The addition of estrogen levels in birth control releases extra secretions of renin-angiotensin into the kidneys, which causes more water to be held, accompanied with sodium retention.

Metabolism

• Birth control can cause a rise in insulin levels, termed insulin resistance, according to Dr. Frederick R. Jelovsek. This insulin resistance turns the carbohydrates in the body into fatty cells rather than useful energy.

Dosage

• Contraceptives that contain a level higher than 30 micrograms can cause weight gain.