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Prospective evaluation of the impact of intermenstrual bleeding on natural fertility

Natalie M Crawford¹, David A Pritchard², Amy H Herring²

¹Department of Obstetrics and Gynecology, University of North Carolina, Chapel Hill, North Carolina.

Fertility and Sterility

|January 29, 2016

Abstract

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.

Keywords:

Bleeding fecundability intermenstrual bleeding luteal bleeding natural fertility

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