Peri implantation intercourse lowers fecundability

Two or more acts of intercourse during the peri-implantation window is associated with a lower probability of pregnancy given prior intercourse during the fertile window.

Anne Zweifel Steiner, M.D., M.P.H., David Pritchard, M.S., Steven L. Young, M.D., Ph.D., Amy H. Herring, Sc.D.

Volume 102, Issue 1, Pages 178–182


To determine the impact of sexual intercourse around the time of implantation on the probability of achieving a pregnancy.

Time-to-pregnancy cohort using day-specific probability of pregnancy modeling to account for intercourse during the fertile window.

Community cohort.

Women trying to conceive naturally, ages 30–44, without known infertility.


Main Outcome Measure(s):
Positive pregnancy test.

A total of 564 women provided 1,332 complete cycles for analysis. Intercourse frequency during the fertile window and during the peri-implantation window were significantly correlated. Cycles in which couples had 2 or more days with intercourse during the implantation window were significantly less likely to result in a positive pregnancy test compared with cycles in which couples did not have intercourse in this window, after adjusting for age, race, history of regular menstrual cycles, previous pregnancy, and body mass index (fecundability ratio, 0.62; 95% confidence interval, 0.42–0.91).

Intercourse during the peri-implantation window may be detrimental to natural fertility. Methods that allow couples to time intercourse to the fertile window may decrease time to pregnancy by not only increasing the probability of fertilization but also decreasing the probability of failed implantation.

  • Lauren Johnson

    Congratulations to Dr. Steiner and colleagues on this provocative finding from the TTC cohort. The authors demonstrate that two or more acts of intercourse in the
    peri-implantation window was associated with lower cycle fecundability among women
    without a history of infertility attempting to conceive naturally. The authors’
    ability to control for frequency of intercourse during the fertile window is a
    key strength of this analysis and provides the best evidence to date that
    uterine contractions around the time of implantation may be detrimental. Nicely

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