The age pattern of fecundability: an analysis of French Canadian and Hutterite birth histories.
Level 4 - case-series / case-control
Historical demographic cohort modeling (graded by design analogy, not clinical CEBM)
PubMed 11521455 · doi:10.1080/19485565.2000.9989008
What was done
The authors applied a convolution model of fecundability to assess age-related patterns of effective fecundability in populations without deliberate birth control. The analysis evaluated two historical cohorts: mid-20th-century Hutterite birth histories and 17th-to-18th-century French Canadian birth histories.
What was found
The abstract provides no specific numerical values, rates, or confidence intervals. It reports that effective fecundability was higher in French Canadians than in Hutterites, peaking at age 20 in Hutterites and in the early to mid-20s in French Canadians. Fecundability declined almost linearly from age 20 to 45 in Hutterites, but declined slowly until the early 30s before falling more rapidly in French Canadians. Postpartum amenorrhea was longer among French Canadians, resulting in similar average numbers of children between both groups.
Why it matters
The study models natural human fecundability patterns across reproductive ages in non-contracepting historical populations, showing how biological fecundability and postpartum amenorrhea interact to shape overall fertility.
Limits
The abstract reports no sample sizes or quantitative estimates. The findings depend on mathematical modeling assumptions applied to historical demographic records, which may be subject to historical recording inaccuracies and cannot directly capture unmeasured modern biological or environmental factors.
Cited by
- context A woman's ability to conceive declines linearly starting from age 20.