Wesselink AK, et al. - The relationship between female and male age with fecundability was investigated in this study. In this pre-conception cohort study of North American pregnancy planners, increasing female age was related to an approximately linear decline in fecundability. While researchers found little relationship between male age and fecundability, the small number of men in this study over age 45 years limited the ability to draw conclusions on fecundability in older men.

Methods

• For this research, they designed a web-based preconception cohort study.
• This study was conducted on the pregnancy planners from the United States and Canada.
• In this study, participants enrolled between June 2013 and July 2017.
• Participants were 21-45 years old females or ≥ 21 years old males.
• Qualified participants were not using fertility treatments.
• Couples were followed until pregnancy or for up to 12 menstrual cycles.
• They examined data from 2,962 couples who had been trying to conceive for ≤3 cycles at study entry and reported no history of infertility.
• They utilized life-table methods to estimate the unadjusted cumulative pregnancy proportion at 6 and 12 cycles by female and male age.
• They utilized proportional probabilities regression models to estimate fecundability ratios, the per-cycle probability of conception for each age category relative to the referent (21-24 years), and 95% confidence intervals.

Results

• Among females, the unadjusted cumulative pregnancy proportion at 6 cycles of attempt time ranged from 62.0% (age 28-30 years) to 27.6% (age 40-45 years); the cumulative pregnancy proportion at 12 cycles of attempt time ranged from 79.3% (age 25-27 years) to 55.5% (age 40-45 years).
• Similar patterns were seen among males, although differences between age groups were smaller.
• After adjusting for potential confounders, they observed a nearly monotonic decline in fecundability with increasing female age, with the exception of 28-33 years, where fecundability was relatively stable.
• Fecundability ratios were 0.91 (95% confidence interval: 0.74-1.11) for ages 25-27, 0.88 (95% confidence interval: 0.72-1.08) for ages 28-30, 0.87 (95% confidence interval: 0.70-1.08) for ages 31-33, 0.82 (95% confidence interval: 0.64-1.05) for ages 34-36, 0.60 (95% confidence interval: 0.44-0.81) for ages 37-39, and 0.40 (95% confidence interval: 0.22-0.73) for ages 40-45, compared with the reference group (ages 21-24 years).
• The relationship was stronger among nulligravid women.
• Male age was not appreciably connected with fecundability after adjustment for female age, although the number of men over age 45 years was small (n=37).