Peri-implantation intercourse lowers fecundability

Abstract

Objective To determine the impact of sexual intercourse around the time of implantation on the probability of achieving a pregnancy. Design Time-to-pregnancy cohort using day-specific probability of pregnancy modeling to account for intercourse during the fertile window. Setting Community cohort. Patient(s) Women trying to conceive naturally, ages 30-44 without known infertility. Intervention(s) None. Main Outcome Measure(s) Positive pregnancy test Result(s) A total of 564 women provided 1,332 complete cycles for analysis. Intercourse frequency during the fertile window and during the peri-implantation window was 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 to cycles in which couples didn’t 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). Conclusions 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.

Lifestyle and pregnancy loss in a contemporary cohort of women recruited before conception: The LIFE Study

“…We first modeled each lifestyle behavior separately during each of the sensitive windows then included potential confounders that were identified a priori based on a review of the literature: female age (18), couples ages modeled as the difference (years) given their known correlation and reports of male age being associated with loss (10), couples’ BMI (continuous) (19,20) sexual frequency (21), and prior history of loss conditional on gravidity (22). Using Cox’s proportional hazards model (23), we modeled time to loss (post-conception days) to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) after first assessing potential non-linear relationships using splines.…”

Optimal timing for elective egg freezing

“…For women ages 25–40, the probability of marriage prior to the Horizon Age was calculated from the National Survey of Family Growth (Supplemental Figure 1a (7-year Horizon shown)) (12). The data for unassisted conception rates after 6 months was derived from 626 women enrolled in an ongoing time-to-pregnancy study, Time to Conceive, as previously described (Supplemental Figure 1b (7-year Horizon shown)) (13). After unassisted conceptions, the age-based LBR versus miscarriage was estimated from a large prospective national register linkage study of over 1.2 million pregnancies in Denmark (Supplemental Figure 1c (7-year Horizon shown)) (14).…”

Sperm intrusion into the implantation-stage blastocyst and its potential biological significance

“…This phenomenon might reflect a scenario of parent–offspring conflict [ 14 ] and could possibly explain at least in part a reported observation of why frequent coitus around implantation in women may reduce the probability of a positive pregnancy test [ 15 ]. However, a high-powered and a better-controlled study conducted subsequently failed to confirm that frequent coitus around implantation indeed affected fecundability in women [ 16 ].…”