Miscarriages/Spontaneous Abortions and Paternal Age

Advancing paternal age has been found to be a potent factor in some miscarriages.

Various recent studies have found this:

The frequency of chromosomal anomalies in spermatozoa appears to increase with male age. Because these anomalies play a role in the etiology of spontaneous abortion, an influence of paternal age on risk of spontaneous abortion is plausible but not established. The aim was to characterize this influence in a prospective study among 5,121 California women, who as members of a prepaid health plan were interviewed in 1990 or 1991 when they were less than 13 weeks' pregnant and who were followed until the end of pregnancy. The risk of spontaneous abortion between weeks 6 and 20 of pregnancy was studied using a Cox model adjusted for maternal age. The adjusted hazard ratio of spontaneous abortion associated with paternal age of 35 years or more, compared with less than 35 years, was 1.27 (95% confidence interval: 1.00, 1.61), with no modification by maternal age. Among women aged less than 30 years, the hazard ratio of spontaneous abortion associated with paternal age of 35 years or more was 1.56 for first trimester spontaneous abortion and 0.87 for early second trimester spontaneous abortion (test of interaction, p = 0.25). In conclusion, the risk of spontaneous abortion increased with increasing paternal age, with a suggestion that the association is stronger for first trimester losses.

another recent study


RESULTS: The adjusted odds ratio for spontaneous abortion was 0.59 (95% confidence interval 0.45–0.76, P< .0001) for pregnancies conceived from fathers aged younger than 25 years compared with those from fathers aged 25–29 years. For fathers age 40 years or older the odds ratio for spontaneous abortion was 1.6 (95% confidence interval 1.2–2.0, P=.0003) when compared with the same reference group.

CONCLUSION: Increasing paternal age is significantly associated with spontaneous abortion, independent of maternal age and multiple other factors.

LEVEL OF EVIDENCE: II-2