Abstract
Objectives: To assess whether there are differences in fertility between adults born very preterm or at very low birth weight (VP/VLBW) with term-born controls, whether the association of VP/VLBW with fertility differs by sex, and which individual factors are associated with fertility among VP/VLBW adults.
Study design: Prospective longitudinal cohorts with fertility assessed in VP/VLBW and term-born adults were identified from two international consortia: Research on European Children and Adults Born Preterm (RECAP-Preterm), and Adults Born Preterm International Collaboration (APIC). Individual participant data (IPD) on neonatal, medical, sociodemographic, and fertility variables were collected and analyzed using a one-stage approach.
Results: Seven cohorts with 931 VP/VLBW and 1363 term-born young adults (mean ages at assessment ranged from 23 to 30 years) were included. VP/VLBW and term-born young adults did not significantly differ in fertility (i.e., having children) (OR 1.48, 95 % CI 0.99-2.21). No moderation effect of sex could be confirmed (OR 0.87, 95 % CI 0.53-1.42). Among VP/VLBW young adults, higher fertility was significantly associated with female sex, higher age at assessment, being married/cohabiting, the absence of childhood neurosensory impairment, and low levels of maternal and own education.
Conclusions: VP/VLBW is not associated with lower fertility in young adults. Sex does not moderate this association. In addition to childhood neurosensory impairment, mainly sociodemographic factors (partnering, maternal and own education) are associated with fertility in VP/VLBW young adults. The evidence is limited so far to the early reproductive window in the 20 s, further follow-up into established adulthood will be required for definite answers on fertility after VP/VLBW birth.