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Published on: November 28, 2018
Time trends in human fecundability in Sweden
Thomas H Scheike1, Lars Rylander, Lisbeth Carstensen
1Department of Biostatistics, University of Copenhagen, Denmark. T.Scheike@biostat.ku.dk
Epidemiology (Cambridge, Mass.)
|January 29, 2008
Summary
Subfertility, defined as taking over a year to achieve pregnancy, decreased across birth cohorts in Sweden. This trend suggests improving couple fecundability over time, despite some age-related increases.
Area of Science:
- Reproductive epidemiology
- Demographic health trends
Background:
- Assessing trends in human fertility is challenging, with ongoing debate regarding male reproductive health impacts.
- Time-to-pregnancy (TTP) serves as a key functional indicator of couple fecundability.
Purpose of the Study:
- To analyze trends in subfertility using Time-to-pregnancy (TTP) data.
- To investigate the influence of maternal age and birth cohort on subfertility.
Main Methods:
- Analysis of TTP data from 832,000 primiparous women in Sweden (1983-2002).
- Subfertility (TTP ≥ 1 year) was examined in relation to maternal age, calendar time, and birth cohort.
- Consideration of retrospective sampling biases inherent in birth registry data.
Main Results:
- A general decrease in subfertility was observed across successive birth cohorts.
- A temporary rise in subfertility occurred in the early 1990s.
- Subfertility increased with maternal age, with a notable exception for women in their late 30s in earlier cohorts.
Conclusions:
- The study identified a declining trend in subfertility over the study period.
- Potential contributing factors include reduced sexually transmitted diseases, shifts in sexual behavior, or broader societal changes.
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