Last March, I reported on a study showing that women who used the progesterone-only birth control shot, Depo Provera, gained an average of 11 pounds over three years and experienced a 3 percent increase in body fat. That compares with an average weight gain of 3 to 4 pounds and less than half the increase in body fat for those who used other forms of contraception. I had asked study author Abbey Berenson what distinguished the one quarter of Depo users who gained a significant amount of weight—upwards of 20 pounds—from those who didn't gain much at all. She told me she didn't know but would be looking at that in her next study.
Well, those results were published this week in the journal Obstetrics & Gynecology. It found that women who start getting Depo shots and go on to gain an average of 24 pounds over three years have these things in common:
Early gainers: Their weight increased soon after starting the shots—an increase of 5 percent over their starting body weight within the first six months.
Not obese: They tended to have a body mass index under 30, or less than 175 pounds for a 5-foot, 4-inch woman.
Moms: They had children before going on Depo Provera.
Hungrier: They experienced an increase in appetite after being on the shots for six months.
Bottom line: Women who don't gain significant amounts of weight within their first six months on Depo probably don't need to worry about longer-term weight increases as a result of the contraceptive. Those who do gain more than a couple of pounds would be better off switching to a different form of contraception.