Prospective evaluation of the impact of intermenstrual bleeding on natural fertility.
OBJECTIVE: To evaluate the impact of an episode of intermenstrual bleeding on the probability of conception in a menstrual cycle (fecundability). DESIGN: Prospective, time-to-pregnancy cohort study. SETTING: Community-based cohort. PATIENT(S): Women trying to conceive, ages 30 to 44 years, without known infertility. INTERVENTION(S): Not applicable. MAIN OUTCOME MEASURE(S): Current cycle and subsequent cycle fecundability. RESULT(S): A total of 549 women provided 1,552 complete cycles for analysis. Intermenstrual and luteal bleeding were reported in 36% and 34% of cycles, respectively. Ninety-three percent of all intermenstrual bleeding was luteal. Cycles in which women had intermenstrual bleeding or luteal bleeding were statistically significantly less likely to result in conception (fecundability ratio [FR] 0.23; 95% confidence interval [CI], 0.16-0.34; and FR 0.22; 95% CI, 0.14-0.33). Women with an episode of intermenstrual and luteal bleeding had a statistically significant increase in the probability of pregnancy in the subsequent cycle (FR 1.61; 95% CI, 1.15-2.25; and FR 2.01; 95% CI, 1.52-2.87, respectively). CONCLUSION(S): Intermenstrual bleeding statistically significantly decreases the odds of conceiving in that cycle but does not appear to negatively impact a woman's immediate future reproductive potential. CLINICAL TRIAL REGISTRATION NUMBER: NCT01028365.
Crawford, NM; Pritchard, DA; Herring, AH; Steiner, AZ
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