By Rebecca H. Allen, MD, MPH
Assistant Professor, Department of Obstetrics and Gynecology, Warren Alpert Medical School of Brown University, Women and Infants Hospital, Providence, RI
Dr. Allen reports she is a consultant for Activis and Bayer and receives grant/research support from Bayer.
Synopsis: In this prospective cohort study, perceived weight gain was found to be an adequate predictor of actual weight gain. Depot medroxyprogesterone acetate and the contraceptive implant were associated with more weight gain than the copper IUD.
Source: Nault AM, et al. Validity of perceived weight gain in women using long-acting reversible contraception and depot medroxyprogesterone acetate. Am J Obstet Gynecol 2013;208:48.e1-8.
The authors performed a two-part analysis of the Contraceptive CHOICE Project, a prospective cohort study in which women in the St. Louis, Missouri, region received a reversible contraceptive method of their choice for up to 3 years at no cost. First, body mass index was calculated at enrollment and women were asked at 3-, 6-, and 12-month telephone interviews whether their weight had changed by 5 pounds or more. This perceived weight change was categorized as weight gain, no change, or weight loss. Second, a smaller cohort of women from the main study then were asked to return at 12 months for an objective weight measurement. They had to have been using the levonorgestrel IUS (LNGIUS), copper T380A IUD (Cu-IUD), contraceptive implant, or depot medroxyprogesterone acetate (DMPA) for at least the prior 11 months. Participants were classified as having had weight gain if the calculated weight change was ≥ 5 pounds, no change if the calculated weight was < 5-pound difference in either direction, or weight loss if the calculated weight change was ≤ 5 pounds or less.
A total of 4133 women met inclusion criteria for the first part of the study, and 281 of those had an objective weight measurement at 12 months. Women who perceived weight gain were more likely to be African American, parous, uninsured, and less educated. Forty-six percent of DMPA users, 41% of implant users, 34% of LNGIUS users, 29% of copper IUD users, and 26% of pill/path/ring users reported a perceived weight gain. The mean weight change for the 281 women with objective measurements was a 2.2 pound increase. Women who perceived weight gain experienced a mean of 10.3 pounds gained. Women who perceived no change to their weight experienced a mean of 1.5 pounds gained. Women who perceived weight loss experienced a mean of 9.5 pounds lost. The sensitivity and specificity of perceived weight gain was 74.6% and 84.4%, respectively, and the positive predictive value was 77%. Having established that perceived weight gain was reasonably predictive of actual weight gain, the authors then used the larger cohort to perform a multivariable analysis. After adjusting for race, the implant (relative risk [RR] 1.29; 95% confidence interval [CI], 1.10-1.51) and DMPA (RR 1.37; 95% CI, 1.14-1.64) users were significantly more likely to perceive weight gain compared with copper IUD users.
COMMENTARY
Long-acting reversible contraception (LARC), due to its high efficacy and continuation rates, is considered to be in the top tier of contraceptive efficacy. We should encourage more women who need long-term contraception to choose IUDs and implants. The Contraceptive CHOICE Project investigators have previously reported continuation rates at 12 months of 88% for the LNGIUS, 84% for the Cu-IUD, and 83% for the subdermal implant.1 Satisfaction rates were also higher for LARC methods compared to other methods of contraception such as oral contraceptives and DMPA. One component of contraceptive continuation and satisfaction is weight gain, whether actual or perceived. Clinically, we see many women requesting to change contraceptive methods because of perceived weight gain, although whether the weight gain is due to the method or changes in diet and activity is often not known. This is an important conversation to have with your patient. This study assigns an overall average 2.2 pound potential weight gain across all methods. Although most women are adverse to any weight gain, the benefit of LARC and security against pregnancy may be worth the gamble, especially since pregnancy is associated with weight gain that often persists into the postpartum. Therefore, switching women from a highly effective contraceptive will likely increase their risk of pregnancy at the cost of a few pounds. The choice is highly personal and worth the discussion.
This particular study examined the validity of perceived weight gain among women using LARC methods and DMPA against actual weight gain — a highly practical outcome for our population. It has long been known that DMPA use can be associated with weight gain, especially in women who are already obese.2,3 In the trials for the contraceptive implant, however, mean weight gain in U.S. users was 2.8 pounds in the first year and 3.7 pounds after 2 years. Additionally, only 2.3% of the study population requested that the implant be removed due to weight gain.4 Interestingly, the authors found that more women using both implants and DMPA, compared to IUDs and the pill/patch/ring, reported perceived weight gain. Perceived weight gain with the contraceptive implant has not been previously described. Although perceived weight gain was not a perfect measure of actual objective weight gain, it was a reasonable approximation associated with decent sensitivity, specificity, and predictive value. Nevertheless, the authors did not report the actual weight gain with each method among the 281 women, which would have been helpful information. In addition, there is no information on diet and exercise habits in the participants.
The investigators propose that providers caring for women using these contraceptives should ask them about weight gain, and that perceived weight gain can be just as concerning to women as actual weight gain. They suggest interventions, such as weight loss counseling and screening for diseases associated with obesity, including hypertension or diabetes. They do not mention any strategies for changing the contraceptive method or at what weight gain threshold it should be changed. Because of the known association, women on DMPA are likely already monitored closely for weight gain. In our clinic, all patients on DMPA have their weight and blood pressure checked at each injection visit. Implant users typically present only for their annual gynecologic exams after implant insertion, unless side effects are bothersome. Changes in weight are already addressed as part of an annual exam evaluation, but this study may make us pay more attention in contraceptive implant users.
References
- Peipert JF, et al. Obstet Gynecol 2011;117:1105-1113.
- Berenson AB, Rahman M. Am J Obstet Gynecol 2009;200:329 e1-8.
- Bonny AE, et al. Arch Pediatr Adolesc Med 2006;160:40-45.
- Merck. www.merck.com/product/usa/pi_circulars/n/nexplanon/nexplanon_pi.pdf. Accessed Jan. 22, 2013.
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