The Pill May Hurt Women's Muscles

Active women who take oral contraceptives makes it harder for women to gain muscle, according to a report by researchers at Texas A&M University.

The scientists wanted to see how birth control pills affect women's bodies. They took 73 women between the ages of 18 and 31 and split them into two groups, based on whether they were on the pill.

The women did a 10-week program of weight training, especially for the upper body. They were encouraged to eat enough protein to help build muscle.

They found that both groups made similar gains in strength and muscle size. But, they also found that women on the pill gained about 2.1 percent lean muscle mass. Women who do not take the pill gained about 3.5 percent.

Anabolic hormones -- those that build muscle -- were also higher in women who do not use oral contraceptives.

The researchers said in a news release that they were surprised by the differences in muscle gains.