Paternal age and preterm birth in Italy, 1990 to 1998.

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.