Body weight and risk of oral contraceptive failure.
ABSTRACT To examine the hypothesis that higher body weight increases the risk of oral contraceptive (OC) failure.
We conducted a retrospective cohort analysis of data from 755 randomly selected female enrollees of Group Health Cooperative of Puget Sound who completed an in-person interview and dietary questionnaire between 1990 and 1994 as control subjects for a case-control study of ovarian cysts. Among the 618 women who were OC ever-users, we used Cox proportional hazards regression models to estimate the relative risk (RR) of pregnancy while using OCs associated with body weight quartile.
During 2822 person-years of OC use, 106 confirmed pregnancies occurred (3.8 per 100 person-years of exposure). After controlling for parity, women in the highest body weight quartile (70.5 kg or more) had a significantly increased risk of OC failure (RR 1.6, 95% confidence interval [CI] 1.1, 2.4) compared with women of lower weight. Higher elevations of risk associated with the highest weight quartile were seen among very low-dose OC users (RR 4.5, 95% CI 1.4, 14.4) and low-dose OC users (RR 2.6, 95% CI 1.2, 5.9), controlling for parity, race, religion, and menstrual cycle regularity.
Our findings suggest that body habitus may affect metabolism sufficiently to compromise contraceptive effectiveness. Consideration of a woman's weight may be an important element of OC prescription.
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ABSTRACT: Abstract Background: Recent studies have examined the relationship between body mass index (BMI) and sexual behaviors, but little information exists on this relationship among racially diverse, low-income women using objectively measured clinical data. The purpose of this study was to examine the association between BMI and sexual behaviors, rates of sexually transmitted infections (STIs) and unintended pregnancy, and contraceptive adherence among adolescent and young adult women. Methods: As part of a larger study, 1,015 Hispanic (54.2%), Black (18.6%) and White (24.8%) women aged 16 to 24 years seeking family planning services at publicly funded reproductive health clinics provided data on their baseline sexual behaviors, and contraceptive use and pregnancy history over 12 months. Objective clinical data were available from medical records at baseline (i.e., height, weight, and Papanicolaou [Pap] smear results), and over a 12-month period (i.e., STI results). Multivariable analyses were used to compare sexual behaviors, STI rates, contraceptive compliance, and unintended pregnancy rates between obese, overweight, and normal weight participants after adjusting for age, race/ethnicity, and other confounders. Results: Overall, 423 (36.6%), 304 (26.3%), and 288 (24.9%) participants were classified as normal weight, overweight, and obese, respectively. No statistically significant association was observed between BMI and sexual behaviors, STI rates (overweight odds ratio [OR] 0.67; 95% confidence interval [95% CI] [0.4, 1.08]; obese OR 0.68; 95% CI [0.42, 1.10]); contraceptive compliance (overweight OR 0.89; 95% CI [0.69, 1.16]; obese OR 0.89; 95% CI 0.68, 1.16]), or unintended pregnancy (overweight OR 1.08 95% CI [0.73, 1.60]; obese OR 1.09; 95% CI [0.72, 1.63]). Conclusion: STI history and contraceptive compliance did not vary by BMI. Therefore, all women should receive equal contraceptive counseling (including condoms) to reduce the risk of unplanned pregnancy and STIs.Journal of Women's Health 10/2013; DOI:10.1089/jwh.2012.4116 · 1.90 Impact Factor
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ABSTRACT: Purpose This study aimed to describe frequency of sexual intercourse and whether body size was associated with weekly sexual intercourse among a diverse group of women using oral contraceptives. Methods This longitudinal, prospective cohort study recruited participants (n=185) from several clinics in Charlotte, NC. Body mass index (BMI) and waist-to-hip ratio (WHR) were used as measures of body size and sexual intercourse frequency was determined from self-reported information provided on daily diaries. Mean monthly frequencies of sexual intercourse were calculated and linear mixed models were used to assess if means remained constant over time. Generalized estimating equations were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Results Mean monthly frequency of sexual intercourse was similar for women classified as normal/underweight or obese by BMI during each month of data collection, but was highest for women classified as overweight. After adjustment, obesity-sexual intercourse associations were attenuated (BMI >30 vs. <25.0: OR=0.78, 95% CI: 0.43, 1.42 and WHR >0.85 vs. <0.85: OR=1.11; 95% CI: 0.62, 2.01). Conclusions This study found no association between BMI or WHR and weekly sexual intercourse. However, more research is warranted given the importance of this possible relationship for future studies of fertility, contraceptive effectiveness, and sexual health.Annals of Epidemiology 09/2014; 24(9). DOI:10.1016/j.annepidem.2014.06.004 · 2.15 Impact Factor
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ABSTRACT: Background Body mass index (BMI) may influence ovulation inhibition resulting from transdermal hormone delivery. Investigation of this effect is important given the high prevalence of obesity in the US. Study Design This open-label, uncontrolled, Phase 2b trial stratified 173 women (18–35 years) according to three BMI groups (Group 1, n = 56, ≤ 30 kg/m2; Group 2, n = 55, > 30 kg/m2 and ≤ 35 kg/m2; and Group 3, n = 47, > 35 kg/m2). Women used a contraceptive patch containing 0.55 mg ethinyl estradiol (EE) and 2.1 mg gestodene (GSD). The EE/GSD patch was used weekly for three 28-day cycles (one patch per week for 3 consecutive weeks followed by a 7-day, patch-free interval) and its effect on ovulation was assessed by the Hoogland score, a composite score that comprises transvaginal ultrasound and estradiol (E2) and progesterone levels every 3 days in Cycles 2 and 3. Evaluation of PK parameters was a secondary aim of the study, and blood samples for analytic determination of EE, GSD and SHBG were taken during the pre-treatment cycle, Cycle 2 and Cycle 3. Compliance was assessed using diary information and serum drug levels. Results In the per-protocol set, there were only six ovulations during the study, and no participant ovulated in both study cycles. One ovulation occurred in Group 1, three in Group 2, and two in Group 3. Ovulation inhibition was unaffected by BMI; in all groups, most participants had Hoogland scores of 1 or 2 (i.e. follicle-like structures < 13 mm (Group 1, ≤ 30 kg/m2, 80.0% in Cycle 2, 85.7% in Cycle 3; Group 2, > 30 kg/m2 and ≤ 35 kg/m2, 61.4% in Cycle 2, 75.0% in Cycle 3; Group 3, > 35 kg/m2, 78.0% in Cycle 2, 72.5% in Cycle 3). Serum levels of follicle-stimulating hormone, luteinizing hormone, E2 and progesterone were similar between groups. Body weight had a limited effect on EE clearance that was unlikely to be clinically relevant. Conclusion The EE/GSD patch provided effective ovulation inhibition, even in women with higher BMI. Implications This is the largest-to-date study of physiologic endpoints and found no clinically important differences in ovarian suppression among obese and normal-weight users of the EE/GSD contraceptive patch, thus providing reassurance that obese women can achieve the same high level of contraceptive protection as normal-weight users.Contraception 09/2014; 90(3). DOI:10.1016/j.contraception.2014.04.018 · 2.93 Impact Factor