Design: systematic review and meta-analysis of observational studies, GRADE certainty low to very low
Population: 34 studies of postmenopausal women without prior cardiovascular disease; 18 studies pooled
Primary outcome: cardiovascular morbidity and mortality by reproductive factor
Effect: later menopause 0.94 per 5 years (95% CI 0.90-0.98); parity 0.99 (0.96-1.01); pregnancy loss 1.22 (0.93-1.61)

A systematic review gathered 34 observational studies, 18 of them poolable, on reproductive factors and cardiovascular outcomes in postmenopausal women with no prior cardiovascular disease. Effect estimates were combined on the log scale, with risk of bias assessed by Joanna Briggs Institute tools and certainty by GRADE.

Only one factor held up. Later age at menopause was associated with fewer cardiovascular events, with a pooled estimate of 0.94 per five-year increase (95% CI 0.90-0.98) — though no clear association appeared for cardiovascular mortality. Number of children (0.99, 0.96-1.01) and age at first childbirth (0.99, 0.97-1.00) showed little or no association. A history of pregnancy loss gave 1.22 (0.93-1.61) overall, and the estimate moved when individual studies were removed.

Evidence on type of menopause — surgical against natural — and on hormonal contraceptive use was too limited and too heterogeneous to pool at all. Certainty across the review ranged from low to very low, with substantial heterogeneity in most analyses.

The practical value here is subtractive. A reproductive history taken for cardiovascular risk stratification is worth taking, but this review does not support weighting parity or age at first birth, and the pregnancy-loss association is not secure enough to act on. Age at menopause is the item to record and revisit.

Record age at menopause in the cardiovascular risk history — it is the reproductive factor with the most consistent association
Do not weight parity or age at first childbirth when estimating cardiovascular risk; neither showed an association here
Treat a history of pregnancy loss as a reason to assess conventional risk factors, not as an independent risk multiplier on this evidence
For a woman with early or surgical menopause, base advice on the established risk factors rather than on this synthesis, which could not pool that comparison
Use a validated risk score as the anchor; reproductive history supplements it rather than replacing it

Why it matters

Reproductive history is routinely collected for cardiovascular risk, and most of what is collected turns out not to carry information.

The statistics, in plain English

A pooled estimate of 0.94 per five-year increase, with an interval from 0.90 to 0.98, sits entirely below 1.0 — a modest association, but a consistent direction. The parity and age-at-first-birth estimates sit almost exactly on 1.0 with narrow intervals, which is a genuine finding of no association rather than a failure to detect one. The pregnancy-loss interval, 0.93 to 1.61, crosses 1.0 and is wide, so it is uninformative. Substantial heterogeneity and GRADE certainty of low to very low mean all of these are associations from observational data, not effects.