Birth control shot linked to weight gain

GALVESTON, Texas, March 5 (UPI) -- Women who get the birth control shot gained an average of 11 pounds and increased their body fat by 3.4 percent over three years, U.S. researchers said.

However, researchers at the University of Texas Medical Branch in Galveston said women who switched to non-hormonal contraception began to slowly lose the weight and fat mass they gained -- nearly 4 pounds over two years, while those who used oral contraception after the shots gained an average of four additional pounds in the same time span.

The amount of weight gain was dependent on the length of time depot medroxyprogesterone acetate, commonly known as the birth control shot, was used, as the rate of weight gain slowed over time.

The study, published in the American Journal of Obstetrics and Gynecology, said depot medroxyprogesterone acetate is an injected contraceptive administered to patients every three months, which is used by some 2 million American women.

"Women and their doctors should factor in this new data when choosing the most appropriate birth control method," lead author Dr. Abbey Berenson said in a statement.

The study tracked 703 women in two age groups age 16-24 and 25-33 using Depot medroxyprogesterone acetate, oral or non-hormonal -- bilateral tubal ligation, condom or abstinence -- contraception for three years.

When researchers compared all three groups, depot medroxyprogesterone acetate users were more than twice as likely as women using non-hormonal or oral birth control to become obese over the next three years, the study said.