Delayed childbearing and reproductive ageing: a narrative review.

内容摘要

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. Many people are choosing to have children later in life. This reflects positive social changes – such as more education and career opportunities for women. However, it also creates challenges because female fertility naturally declines with age, especially after 35. This review explains how and why age affects fertility.In women, both the number and quality of eggs decrease over time. Problems with energy production in egg cells (mitochondria) and errors in chromosome division lead to higher miscarriage rates and lower success with fertility treatments. The womb (uterus) also ages, making it harder to maintain a healthy pregnancy. Older fathers may also contribute to pregnancy risks through changes in sperm DNA.Having a baby at an older age increases the chances of pregnancy complications, including diabetes, high blood pressure, preterm birth and stillbirth. While egg freezing and in vitro fertilisation can help, their success depends strongly on the age at which they are used.For doctors, this means providing clear information about fertility timelines, offering timely treatment and closely monitoring pregnancies in older mothers. For society, it means creating policies – like affordable childcare and parental leave – that help people have children at ages that are both personally right and biologically favourable.