No association between body size and frequency of sexual intercourse among oral contraceptive users.

PURPOSE: This study aimed to describe the 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 or 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.

Comparison of prospective and retrospective measurements of frequency of sexual intercourse.

Measurements of sexual intercourse frequency are informative for research on pregnancy, contraception, and the transmission of sexually transmitted infections; however, efficiently collecting data on this sensitive topic is complex. The purpose of this study was to determine whether retrospective recall of sexual intercourse frequency was consistent with information obtained through the use of prospective daily diary methods corresponding to the same time period in a diverse sample of women. A total of 185 women participated in a longitudinal, prospective cohort study of oral contraceptive users and 98 of these women provided complete information on sexual intercourse frequency on diaries (prospective) and postcards (retrospective). Linear mixed models were used to test for variation in response within categories of demographic and other variables. The mean number of days women had sexual intercourse per week was 1.5 days using prospective diary information versus 2.0 days when using 3-month retrospective recall (p < 0.001). Mean differences for the various sociodemographic subgroups were positive for all groups indicating that women consistently reported a higher frequency of sexual intercourse on the retrospective postcards than they recorded on their prospective diaries; however, these mean differences did not vary significantly. If confirmed in other samples, the use of retrospective methods may be adequate to accurately collect data on sexual intercourse frequency-and may be preferable. Using only retrospective measurements could decrease study costs, the burden to participants, and have a higher response rate.