Contraception, weight gain: Weigh evidence and myths
Contraception, weight gain: Weigh evidence and myths
Counter perceptions with evidence-based counseling
When it comes to weight, patients may discontinue use of hormonal contraception if extra pounds are encountered. Can the method be the culprit?
Add information from an updated review of studies examining the relationship between combined hormonal contraceptive use and weight change to your counseling database. The review continues to find no evidence that combination hormonal contraceptives increase weight.1 The evidence was not strong enough to be sure that these contraceptives do not cause some weight gain, but no major effect on weight was found, researchers conclude.1
When it comes to the Pill and weight gain, women and providers continue to believe that an association exists.1 Such beliefs can lead to avoidance of the method: Four out of 10 women in a 2001 survey said weight gain is a reason to avoid the Pill and they named increased weight as the No. 1 concern when asking about the Pill’s side effects.2 In a national study of adult women, weight gain was the most frequently cited reason for discontinuing oral contraceptive (OC) use.3
To perform the review update, initially published in 2003,4 researchers searched computerized databases for all relevant randomized controlled trials to evaluate the association between combined hormone contraceptive use and change in body weight. Each of the trials included weight measurements for women who were using combination contraceptives for at least three cycles of treatment. Investigators could find no evidence that supported a causal association between combination contraceptives and weight gain.1
Women tend to gain weight over time,5 says Laureen Lopez, PhD, a researcher at Family Health International in Research Triangle Park, NC, and co-author of the review. While on the Pill, they may associate the increase in pounds with Pill use, she surmises.
"One of the concerns is that people may go off a very effective contraceptive thinking that it causes weight when there does not appear to be evidence that it is causing it," Lopez notes.
What about DMPA?
For women who don’t choose the Pill, patch (Ortho Evra, Ortho-McNeil Pharmaceutical, Raritan, NJ), or contraceptive vaginal ring (NuvaRing, Organon, West Orange, NJ), the progestin-only contraceptive injection (depot medroxyprogesterone acetate [DMPA], Pfizer, New York City) represents an attractive birth control option. The shot is popular among adolescents; about 10% of adolescent girls ages 15-19 years use DMPA as their contraceptive method.6,7
A just-published study that looked at adolescent girls initiating DMPA, OC, or no hormonal contraceptive method, found a significant relationship between baseline obesity status and subsequent weight gain.8 Teens who were obese (body mass index kg/m2 30 or above) prior to use of DMPA gained significantly more weight than obese girls starting the Pill or no contraceptive method. In addition, obese adolescents using DMPA gained more weight than did nonobese adolescents using DMPA, OC, or no hormonal contraception method.8
Among teens who were not obese, investigators reported no statistically significant effect of contraceptive method on weight. However, weight gain was greatest among nonobese teens using DMPA, with an average gain of 4 kg at 18 months. This amount of weight gain could be cause for concern in populations vulnerable to obesity, note researchers.
Previous studies have shown variable results when it comes to weight gain in adolescents using DMPA.9-11 According to the DMPA package insert, women using DMPA gain an average of 5.4 pounds in the first year.12 Clinicians need to understand the clinical and behavioral context within which weight gain occurs with DMPA so they can provide better counseling on the method, helping teens to achieve increased method satisfaction and prolonged use, researchers conclude.8
Added weight is becoming more common in adolescents: 15.5% of adolescents ages 12-19 were classified as overweight in 2000; an additional 14.9% of adolescents were at risk for becoming overweight.13 More research should be directed at use of contraception in overweight adolescents, suggests Andrea Bonny, MD assistant professor of pediatrics at Case Western Reserve University in Cleveland and lead author of the DMPA study.
Options for the obese?
Obese women have not been singled out for study in contraception; recent literature14 suggesting that overweight women may be at increased risk for pregnancy while on the Pill may lead more researchers to examine weight’s impact on method efficacy and side effects, says Bonny.
"It would be interesting to start looking at the pharmacokinetics and the pharmacodynamics and seeing if we could tailor drugs based on a woman’s weight to maximize efficacy and minimize side effects," she says.
Limited research has been published on the effects of weight on newer methods such as the contraceptive path and ring. In the clinical trial of the transdermal contraceptive, women who weighed more than 198 pounds comprised 3% of the study population but experienced 30% of the pregnancies recorded in the investigation.15 For the ring, weight does not appear to be a factor in effectiveness; results of a 2005 study indicate similar efficacy in women of all weights enrolled in the investigation.16
As the authors of Contraceptive Technology advise, the best contraceptive method is the one that is medically appropriate and is used every time by someone happy with the method.12 By comparing the risks of contraception vs. the risks of pregnancy in the absence of contraception, clinicians can help very heavy women choose a safe, effective method that is appropriate for their needs.
References
- Gallo MF, Lopez LM, Grimes DA, et al. Combination contraceptives: Effects on weight. The Cochrane Database Systematic Reviews 2006, Issue 1. Art. No.: CD003987.pub2. DOI: 10.1002/14651858.CD003987.pub2.
- National Association of Nurse Practitioners in Women’s Health. Weight, Sexuality, and Women’s Birth Control Decisions. Washington, DC; January 2001. Accessed at: www.npwh.org/executive_summary.htm.
- Rosenberg M. Weight change with oral contraceptive use and during the menstrual cycle: Results of daily measurements. Contraception 1998; 58:345-349.
- Gallo MF, Grimes DA, Schulz KF, et al. Combination contraceptives: effects on weight. Cochrane Database Syst Rev 2003; (2):CD003987.
- Flegal KM, Troiano RP. Changes in the distribution of body mass index of adults and children in the U.S. population. Int J Obes Relat Metab Disord2000; 24:807-818.
- Matson SC, Henderson KA, McGrath GJ. Physical findings and symptoms of depot medroxyprogesterone acetate use in adolescent females. J Pediatr Adolesc Gynecol 1997; 10:18-23.
- Risser WL, Gefter LR, Barratt MS, et al. Weight change in adolescents who used hormonal contraception. J Adolesc Health 1999; 24:433-436.
- Bonny AE, Ziegler J, Harvey R, et al. Weight gain in obese and nonobese adolescent girls initiating depot medroxyprogesterone, oral contraceptive pills, or no hormonal contraceptive method. Arch Pediatr Adolesc Med 2006; 160:40-45.
- Moore LL, Valuck R, McDougall C, et al. A comparative study of one-year weight gain among users of medroxyprogesterone acetate, levonorgestrel implants, and oral contraceptives. Contraception 1995; 52:215-219.
- Matson SC, Henderson KA, McGrath GJ. Physical findings and symptoms of depot medroxyprogesterone acetate use in adolescent females. J Pediatr Adolesc Gynecol 1997;10:18-23.
- Risser WL, Gefter LR, Barratt MS, et al. Weight change in adolescents who used hormonal contraception. J Adolesc Health 1999; 24:433-436.
- Pfizer. Depo-Provera Contraceptive Injection. Physician Information. Accessed at: www.pfizer.com/pfizer/download/uspi_depo_provera_contraceptive.pdf.
- Ogden CL, Flegal KM, Carroll MD, et al. Prevalence and trends in overweight among US children and adolescents, 1999-2000. JAMA 2002; 288:1,728-1,732.
- Holt VL, Scholes D, Wicklund KG, et al. Body mass index, weight, and oral contraceptive failure risk. Obstet Gynecol 2005; 105:46-52.
- Zacur HA, Hedon B, Mansour D, et al. Integrated summary of Ortho Evra/Evra contraceptive patch adhesion in varied climates and conditions. Fertil Steril 2002; 77(2 Suppl 2):S32-35.
- Westhoff C. Higher body weight does not affect NuvaRing’s efficacy. Presented at the American College of Obstetricians and Gynecologists Annual Clinical Meeting. San Francisco; May 2005.
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