Background: Advanced paternal age has been reported to impair pregnancy outcome. Here, we investigated the association of advanced paternal age with preterm birth by using a very large national data set.
Methods: We analyzed data from 1990 to 1998 on Italian firstborn singletons to mothers 20-24 and 25-29 years of age (n = 1,510,823). Odds ratios for overall preterm (<37 weeks' gestation), very preterm (<32 weeks), and moderate preterm (32-36 weeks) births were evaluated through logistic regression models in paternal age classes (20-24, 25-29, 30-34, 35-39, 40-44, 45-49, 50+ years) after adjustment for confounders. Nonparametric regression models were used to fit the effect of paternal ageing on the incidence of very preterm births.
Results: Odds ratios increased with paternal age more rapidly for very preterm than for moderate preterm births; among 45- to 49-year-old fathers, odds ratios for very preterm births reached 1.91 (95% confidence interval = 1.08-3.38) and 1.72 (1.25-2.36), respectively, in 20- to 24- and 25- to 29-year-old mothers.
Conclusions: This study confirms that paternal age contributes to the risk of preterm birth. The effect is stronger on very preterm births but also influences moderate preterm births.