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Contraception Corner

Family Planning for Obese Women: Challenges and Opportunities*

Barbara Clark, RN, MSN, MPH; David Grimes, MD

Many women who rarely consult a physician otherwise will present for a contraceptive prescription, affording a chance to evaluate and counsel for significant health risks—including obesity.

Obesity affects womenÍs reproductive health in terms of contraceptive choices, fertility, and pregnancy. For example, obesity can compromise the efficacy of some contraceptives and increase the technical difficulty of contraceptive procedures. It can also cause pregnancy complications and infertility.

Due to the growing incidence of obesity, physicians will be encountering increasing numbers of women with obesity-related problems. Between 1994 and 2000, the percentage of obese women—ie, body mass index (BMI) 30—rose from 14.6% to 23.3% in those aged 20 to 29 years, from 25.8% to 32.5% in those aged 30 to 39 years, and from 26.9% to 35.4% in those aged 40 to 49 years (Figure).1 The easiest way to determine whether a woman is overweight or obese is to measure BMI. Women with a BMI of 25 to 29.9 are considered overweight, whereas a BMI of 30 is classified as obese.2

Figure not available online

FIGURE. Change in proportion of obese women in the United States by age group, 1988 to 2000.1 NHANES = National Health and Nutrition Examination Survey; BMI = body mass index.

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CONTRACEPTIVE CHOICES


Obese women face particular challenges when choosing contraception because of the association between obesity and decreased efficacy, more health risks, and additional technical problems for some contraceptive methods. Obesity is not always a disadvantage, however: Researchers have found that overweight women who use depot medroxyprogesterone acetate (DMPA) injections have a decreased risk of dysfunctional menstrual bleeding.3 This is a significant finding, as increased/excessive menstrual bleeding often leads women to discontinue DMPA.

Effectiveness

Several recent studies have indicated that obesity can decrease the effectiveness of some forms of hormonal contraception. Although one study on oral contraceptives (OCs) found no association between body weight and accidental pregnancy, a retrospective cohort analysis of 755 women found that those in the highest weight quartile ( 70.5 kg) were at a significantly higher risk of unintended pregnancy—ie, relative risk (RR) of 1.6, 95% confidence interval (CI), 1.1-2.4; this has been supported by other research, and is particularly true for overweight women using low-dose OCs.4-7 A subsequent case-control study in the same population found a similar relationship between pregnancy risk and BMI: A BMI 27.3 raised the risk of pregnancy by 60%, with an odds ratio (OR) of 1.58, 95% CI, 1.11-2.24, and a BMI 32.2 increased the risk by 70% (OR 1.72, 95% CI, 1.04-2.82).8 Among overweight women, this association translates to an additional two to four pregnancies per 100 woman-years of OC use. The researchers hypothesized that excess weight may decrease OC efficacy via alterations in metabolism. A multicenter study of 3,319 women who used the transdermal contraceptive patch also found a significant association between obesity (baseline weight 90 kg) and pregnancy risk (P < .001).9

Weight Gain

Obese women may decide against using OCs or stop using them prematurely due to concern over gaining weight. However, a systematic review of randomized controlled trials found that OCs did not lead to weight gain.10 Accounting for approximately 20% of the 3.5 million unintended pregnancies per year in the United States, women who quit OCs prematurely either fail to immediately substitute another contraceptive method, or may adopt a less reliable method.5

Health Risks

Obese women who use OCs are also at risk for venous thromboembolism (VTE). A meta-analysis showed a significant association in OC users between a BMI of 25 kg/m2 and VTE, and this association grew stronger with a BMI 35 kg/m2. Furthermore, the incidence rises dramatically after age 39 years.11

Technical Difficulties

Insertion of an intrauterine device (IUD) in obese women can pose technical difficulties. It can be difficult to determine the size and direction of the uterus and to visualize the cervix. Using a larger speculum or placing a condom with the tip removed over the speculum blades can improve exposure. Ultrasonographic evaluation before and during IUD insertion my also help.

There are conflicting reports about complications in obese women undergoing tubal sterilization. A retrospective study of women who underwent laparoscopic tubal sterilization found that obesity did not lead to increased complications, mean operating time, or blood loss.12 In a prospective, multicenter cohort study of 9,475 women receiving this procedure, however, obese women had an increased risk of complications (RR 1.7, 95% CI, 1.2-2.6).13 Another cohort study showed low incidences of anesthetic, surgical, and early postsurgical complications for both obese and normal-weight groups.14 The incidence of surgical difficulties was higher in the obese group, though, resulting in a higher technical failure rate and longer surgical time. Therefore, for couples who desire permanent contraception, vasectomy in the male partner may be preferable to tubal sterilization in the obese female partner.

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CONTRACEPTIVE FAILURE

Family planning is critical for women whose health would be threatened by an unplanned pregnancy, and this group includes obese women. When contraception fails in obese women, the consequences can be serious. During pregnancy, obese women are at risk for many conditions that can threaten maternal and fetal health (eg, hypertension, diabetes). In a cohort of 8,092 subjects, researchers reported that overweight women (BMI 25 to 29.9 kg/m2) had ORs of 3.4 for diabetes, 1.9 for hypertension, 1.7 for preeclampsia, and 1.5 for cesarean delivery.15 Obese women (BMI 30 kg/m2) had even higher ORs of 15.3, 4.8, 2.7, and 1.7, respectively.

Abortion also carries risks. For example, a study of 163 obese women who underwent a surgical second-trimester abortion reported that procedure difficulty, operative time, blood loss, and complications increased as BMI rose.16 In addition, in women who have a BMI > 80 kg/m2, it may be impossible to visualize the cervix with a Graves speculum. Placing the patient in a deep Trendelenburg position, increasing lighting, and using lateral retraction may help.17 Medical abortion may be more appropriate for obese women. During the first and second trimesters, research shows that three doses of misoprostol (800 mcg administered vaginally every 12 hours) is a safe and effective approach.18

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COUNSELING

When discussing contraception with obese women, physicians should review the effects of obesity on contraceptive choice, fertility, and pregnancy. This is also an opportune time to counsel the patient about weight loss. According to the US Preventive Services Task Force, intensive counseling and behavioral interventions help to promote sustained weight loss in obese adults.19

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CONCLUSION

Obesity has a significant impact on womenÍs reproductive choices. Further research may facilitate the contraceptive decision, but guiding obese women to an appropriate contraceptive choice is only one part of part of the challenge—and the opportunity. The physician should also use this occasion to promote weight loss by setting up an intervention program or referring the patient for specialized counseling.

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Barbara Clark, RN, MSN, MPH, is a freelance writer in Arlington, Va. David Grimes, MD, is vice president of biomedical affairs, Family Health International; and clinical professor, Department of Obstetrics and Gynecology, University of North Carolina at Chapel Hill School of Medicine. *This article is based on: Grimes DA, Shields WC. Family planning for obese women: challenges and opportunities, published in Contraception. 2005(72)1:1-4.

References

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2. Agency for Healthcare Research and Quality. WhatÍs new from the USPSTF: screening for obesity in adults. Available at: http://www.ahrq.gov/clinic/3rduspstf/obesity/obeswh.htm. Accessed June 30, 2005.
3. Connor PD, Tavernier LA, Thomas SM, Gates D, Lytton SM. Determining risk between Depo-Provera use and increased uterine bleeding in obese and overweight women. J Am Board Fam Pract. 2002;15(1):7-10.
4. Vessey M. Oral contraceptive failures and body weight: findings in a large cohort study. J Fam Plann Reprod Health Care. 2001;27(2):90-91.
5. Rosenberg MJ, Waugh MS, Long S. Unintended pregnancies and use, misuse, and discontinuation of oral contraceptives. J Reprod Med. 1995;40(5):355-360.
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10. Gallo MF, Grimes DA, Schulz KF, Helmerhorst FM. Combination estrogen-progestin contraceptives and body weight: systematic review of randomized controlled trials. Obstet Gynecol. 2004;103(2):359-373.
11. Nightingale AL, Lawrenson RA, Simpson EL, Williams TJ, MacRae KD, Farmer RD. The effects of age, body mass index, smoking, and general health on the risk of venous thromboembolism in users of combined oral contraceptives. Eur J Contracept Reprod Health Care. 2000;5(4):265-274.
12. Singh KB, Huddleston HT, Nandy I. Laparoscopic tubal sterilization in obese women: experience from a teaching institution. South Med J. 1996;89(1):56-59.
13. Jamieson DJ, Hillis SD, Duerr A, Marchbanks PA, Costello C, Peterson HB. Complications of interval laparoscopic tubal sterilization: findings from the United States Collaborative Review of Sterilization. Obstet Gynecol. 2000;96(6):997-1002.
14. Chi IC, Wilkens L. Interval tubal sterilization in obese women—an assessment of risks. Am J Obstet Gynecol. 1985;152(3):292-297.
15. Rode L, Nilas L, Wojdemann K, Tabor A. Obesity-related complications in Danish single cephalic term pregnancies. Obstet Gynecol. 2005;105(3):537-542.
16. Dark AC, Miller L, Kothenbeutel RL, Mandel L. Obesity and second-trimester abortion by dilation and evacuation. J Reprod Med. 2002; 47(3):226-230.
17. Lichtenberg ES, Borgatta L, Grimes DA, Stubblefield PG, Paul M, eds. A ClinicianÍs Guide to Medical and Surgical Abortion. New York, NY: Churchill Livingstone; 1999:169-182.
18. Carbonell JL, Rodriguez J, Delgado E, et al. Vaginal misoprostol 800 microg every 12 h for second-trimester abortion. Contraception. 2004;70(1):55-60.
19. US Preventive Services Task Force. Screening for obesity in adults: recommendations and rationale [Agency for Health Care Research and Quality Web site].
    Available at: http://www.ahrq.gov/clinic/3rduspstf/obesity/obesrr.htm. Accessed June 30, 2005.

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