Delayed childbearing and reproductive ageing: a narrative review

Delayed childbearing is increasingly common worldwide, with more women conceiving at age ≥35 years. This demographic shift intersects with age-related fertility decline, affecting natural conception, assisted reproductive technology (ART) outcomes and perinatal health.

We conducted a narrative review based on structured searches of PubMed, Embase and Web of Science (2015-2025), supplemented by landmark earlier studies. We included peer-reviewed original research, systematic reviews, meta-analyses and clinical guidelines. Findings were synthesised narratively.

Social, economic and cultural factors drive pregnancy postponement, increasing demand for ART. Female reproductive ageing involves declining oocyte quantity and quality, mitochondrial dysfunction, and aneuploidy - reducing fecundability and live birth rates. Advanced maternal age (AMA) elevates risks of gestational diabetes, hypertensive disorders, preterm birth, foetal growth restriction, stillbirth and congenital anomalies. Advanced paternal age independently contributes to miscarriage, preterm birth and offspring neurodevelopmental risks via epigenetic alterations and de novo mutations. Donor oocytes partially offset embryonic decline, but uterine ageing persists, especially after 45 years. Social oocyte freezing offers age-dependent efficacy, with optimal cost-effectiveness when performed in the early 30s.

The health challenges of delayed childbearing may stem from a fundamental mismatch between enabling societal structures and immutable biological timelines. Clinical practice should adopt proactive, age-stratified care that includes preconception education, timely ART, risk-adapted obstetric management and advocacy for supportive social policies.