Weight Influences a Woman's Birth Control Preference

One side effect commonly reported with the birth control pill is weight gain. For this reason, many women go off of the pill and may or may not try alternative, non-hormonal forms of contraception — such as condoms or withdrawal. A study out of the Penn State College of Medicine examined how current weight and weight perception influenced birth control choices.

There are two types of birth control pills — the first contains estrogen and progestin, the second contains only progestin. Many women believe that the estrogen is causing them to gain weight, however, studies concluded that this is a temporary side effect more times than not – and the “gain” is water retention, not fat. Regardless, some women say goodbye to the pill for the sake of their waistlines.

So while research denies the belief that hormonal oral contraceptives add pounds, there are non-hormonal options as well. Long-acting reversible contraceptives (LARCs) — such as intrauterine devices (IUDs) – are one of those options and have been deemed more effective than nonprescription methods.

But does a woman’s body mass index (BMI) have anything to do with their birth control of choice? The researchers determined that it does. They looked at 987 women with private insurance in Pennsylvania ages 18 to 40.

“Women may be worried about weight gain when they’re making decisions about birth control, so clinicians need to be aware of that,” Cynthia H. Chuang, MD, a professor of medicine and public health sciences, said in a news release.

The women were categorized based on contraception method:

• LARCs — 83 women (8.4%)
• Non-LARC prescription methods — 490 women (49.6%)
• Nonprescription methods/no method — 414 women (42%)

The multinomial logistic regression model was controlled for pregnancy intentions, sexual behavior, and sociodemographic characteristics.

It turns out that women who were overweight or obese were significantly more likely to use LARCs than women who were at a normal weight or underweight (23% and 21% vs. 6% and 6%, respectively).

“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. As a result, they are choosing both more effective methods (LARCS) and less effective, non-prescription methods,” Chuang explained.

Further evaluation revealed that compared to women with normal weights, overweight and obese women were also more likely to use non-prescription birth control methods or no method at all. But the results weren’t statistically significant.

Another piece of this study looked at how women’s perception of their weights influenced birth control methods. While half of the women said that they were overweight, only about 42% actually were overweight or obese. However, perception didn’t correlate with contraception choices.

“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 concluded. “It could be an opportunity to counsel women about LARCs, which are more effective forms of contraception.”

The full study, “Does body mass index or weight perception affect contraceptive use?” can be found in the journal Contraception.

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