The perception that weight gain is a common side effect of contraceptive use has been challenged in new guidance from the Faculty of Sexual and Reproductive Healthcare (FSRH).
Weight gain is often cited as a reason why women do not initiate or do not continue contraception, but a review of current evidence for the effect of contraceptive methods on weight concludes that women of reproductive age tend to gain weight over time regardless of use of any contraceptive method.
Public Health England has pointed out that rates of obesity are increasing among women of reproductive age. An increasing number of women who become pregnant are obese – around 19% of women of reproductive age in England are obese, 3.6% are severely obese, and of these obese women 5.3% will become pregnant each year.
The guidance also states that while some users of contraception do gain weight during use, there is no evidence that intrauterine contraception (the IUD and IUS), the implant, the progestogen-only pill or combined hormonal contraception (the combined pill, the patch and the vaginal ring) cause significant weight gain.
Data is currently insufficient to confirm or exclude a causative relationship between use of the contraceptive injection and weight gain.
Women gaining weight over time is not linked to hormonal contraception
The guidance is intended for use by contraceptive providers to support women in making contraceptive choices.
Dr Sarah Hardman, Director of the Clinical Effectiveness Unit of the Faculty of Sexual and Reproductive Healthcare (FSRH), said: “Women often tell us that they do not want to start or to continue contraception because they are worried that it will make them gain weight.
In studies, women gain on average a similar amount of weight over time whether they are using hormonal contraception or not. In other words, women may gain some weight during use of a contraceptive method, but so, on average, do women who are not using contraception.”
“After looking at all the studies available, we can say that average weight gain during use of contraceptive pills, the implant and the hormonal coil is modest and is not significantly different to weight gain with no contraception or non-hormonal contraception."
She added that studies don’t rule out the possibility that some women might gain some extra weight when they are using the contraceptive injection, but stressed that effective contraception was really important to enable women to avoid unplanned pregnancy, and hormonal contraception can have additional benefits like helping with heavy, painful periods.
“Women are all individual: not everyone has the same experience with any method of contraception, ' she said. "The studies confirm that weight change can vary widely between individual women using the same method of contraception (or none). If a woman feels that her contraceptive method isn’t suiting her, I would encourage her to speak to her contraceptive provider about different options so that she can continue to have the benefit of effective contraception.”