Maternal age at birth and daughters' subsequent childlessness

Area of Science:

• Reproductive Epidemiology
• Human Fertility Studies
• Sociodemographic Factors in Health

Background:

• Maternal age at childbearing is rising globally.
• Limited data exists on the impact of advanced maternal age at birth on offspring fertility.
• Understanding this relationship is crucial for public health given trends in delayed childbearing.

Purpose of the Study:

• To investigate whether maternal age at a daughter's birth predicts her likelihood of remaining childless throughout life.
• To assess the association between maternal age at birth and lifelong childlessness in a large cohort study.

Main Methods:

• Analysis of 43,135 women from the US-based Sister Study cohort (born 1930-1964).
• Used multivariable log-binomial models to estimate relative risks (RR) of lifelong childlessness based on maternal age at birth.
• Controlled for covariates including siblings, birth order, socioeconomic status, race, and birth cohort; sibling-matched analysis performed.

Main Results:

• Women born to mothers aged 25-29, 30-34, and ≥35 years had significantly higher risks of childlessness compared to those born to mothers aged 20-24.
• Relative risks (RR) for childlessness were 1.21, 1.30, and 1.40, respectively, for these age groups.
• The association remained consistent across various subgroups and in sibling-matched analyses; paternal age showed a weaker association.

Conclusions:

• Advanced maternal age at birth is associated with an increased probability of lifelong childlessness in daughters.
• The consistent findings across analyses strengthen the evidence for this association.
• Further research is warranted to explore the mechanisms and intentionality of childlessness in relation to maternal age at birth.