About one-third of women report that they seem to gain weight when using a new birth control method, and Gina N. Secura, PhD, MD, from the Washington University School of Medicine, in St. Louis, and colleagues found that after one year of using a new contraceptive, women who perceived weight gain had actually put on an average of 8.8 pounds. Those who reported weight gain had a 74.6% sensitivity and a 84.4% specificity for identifying actual weight gain, the researchers discovered.
The team reported in the American Journal of Obstetrics & Gynaecology, ‘Self-reported weight change is easy to obtain and in most women represents true weight gain. Understanding that some contraceptive methods have higher rates of perceived weight gain could prove helpful to clinicians when counselling their patients.’ Very few studies have, like this one, assessed how women perceive the effect of various contraceptive methods on their weight and whether this perception is accurate, but others have noted a consistent association between depot medroxyprogesterone acetate (DMPA) and weight-gain.
For the study, the researchers examined data from 4,133 new contraceptive method users participating in the Contraceptive CHOICE Project. This was a prospective cohort study to assess the use of long-acting reversible contraception, and the researchers utilised its data to see if self-reported weight gain was useful as a screening tool for actual weight-gain. Via telephone survey, weight change was assessed at three, six, and 12 months.
They found that 34% of the women had perceived weight gain, and this was more likely to occur in participants using the implant method (relative risk=1.29; 95% CI: 1.10–1.51) or DMPA (RR=1.37; 95% CI: 1.14–1.64) than copper intrauterine device users. Of the 114 women who actually gained five pounds or more, 85 had perceived it, whereas of the 167 who did not gain this level of weight, 141 perceived no weight gain.
The researchers concluded, ‘It may be useful, as well as simple and cost effective, to have women report perceived weight changes to their primary care provider at regular intervals. This perceived change may be a trigger for an objective assessment. If validated, the clinician may suggest weight loss strategies or consider screening for diseases associated with obesity, such as diabetes or hypertension.’