Hershey, PA—Even though birth control pills usually don’t cause weight game, some women avoid hormonal contraceptive methods because of the fear of putting on extra pounds, according to a new study.

The research, published in the journal Contraception, found that women who are overweight or obese are less likely than women who are not overweight or obese to use the birth control pill and similar agents.

Weight gain is one of the most commonly cited reasons why women stop using hormonal contraception; that unfounded concern could be playing a role in unintended pregnancies, suggested co-author Cynthia H. Chuang, professor of medicine and public health sciences at Penn State School of Medicine.

The birth-control shot has been associated with weight gain in younger women, but oral contraception rarely has that effect, Chuang explained. Regardless, many women attribute their extra weight to “the Pill.”

To determine if weight or their perception of weight gain influenced the type of birth control they used, the researchers examined demographic and survey data from almost 1,000 privately insured women in Pennsylvania.

Using body mass index (BMI) as a measure, they determined that overweight and obese women were more likely than women who are not overweight or obese to choose forms of birth control known as long-acting reversible contraceptives (LARCs), and less likely to use methods like the pill, the shot, the patch, and the ring.

Nonprescription methods such as condoms, withdrawal, and natural family planning, or no method, also were more likely to be employed by overweight and obese women, according to the study.

Long-acting reversible contraceptives include intrauterine devices, commonly known as IUDs, and the contraceptive implant. LARCs do not contain estrogen, which some some women believe causes weight gain.

“What we think may be happening is that women who are overweight and obese may be more likely to choose methods other than the pill or the shot because of fear of weight gain,” Chuang said. “As a result, they are choosing both more effective methods (LARCS) and less effective, non-prescription methods.”

Overall, 23% of overweight and 21% of obese women were found to be using LARCs, which are the most effective forms of birth control, versus 6% of under-weight and normal-weight women in the study.

“We were actually glad to see that overweight and obese women were at least more likely to choose LARCs because I was expecting to see these women more likely to use non-prescription methods,” Chuang said.

Use of the less effective nonprescription products did not reach statistical significance in the study.

Interestingly, half of the women in the study perceived themselves to be overweight, although only around 42% could be categorized as overweight or obese based on BMI. Perception, however, did not appear to influence birth-control choice.

Healthcare professionals should be aware that weight concerns affect contraception choice, Chuang added, “It could be an opportunity to counsel women about LARCs, which are more effective forms of contraception.”

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