Use of assisted reproductive technologies for male and female infertility and perinatal outcomes.

OBJECTIVE

To compare adverse perinatal outcomes between naturally conceived and pregnancies conceived by assisted reproductive technologies (ARTs) according to underlying male, female, or unexplained infertility.

DESIGN

Registry-based study.

SUBJECTS: All singleton births in Norway between 2000 and 2021 recorded in the national birth registry.

EXPOSURE: We compared ART pregnancies with underlying male (N = 9,957), female (N = 10,031), mixed (N = 3,287), or unexplained (N = 7,178) infertility with naturally conceived pregnancies (N = 1,210,709). Information on underlying causes of infertility was reported from fertility clinics.

MAIN OUTCOMES AND MEASURES: We compared the birthweight and pregnancy length using robust linear regression, and the risk of pre-eclampsia, cesarean section, stillbirth, preterm birth, low birth weight, small-for-gestational age and transfer to neonatal unit using logistic regression, adjusting for parental age, maternal parity, cohabitation, country of birth, and year of delivery.

RESULTS

Pregnancy length and birthweight were lower in all ART groups compared with the naturally conceived. The shorter pregnancy length was less pronounced in ART deliveries resulting from male infertility (adjusted difference -1.24 days; 95% confidence interval [CI]: -1.43 to -1.05) than in ART deliveries resulting from female infertility (adjusted difference -1.92 days; 95% CI: -2.12 to -1.73). Similarly, the lower birthweight in ART deliveries was less pronounced in those resulting from male (adjusted difference -29 grams; 95% CI: -39 to -18) than those resulting from female (adjusted difference -49 grams; 95% CI: -59 to -39) infertility. We also observed a higher risk of most adverse perinatal outcomes in all ART groups, with the magnitude being lower for ART deliveries resulting from male infertility.

CONCLUSION

The increased risk of adverse perinatal outcomes in pregnancies conceived by ART was less pronounced if used for male infertility than for female infertility. This suggests that the risks in ART pregnancies are a combination of underlying factors related to female infertility and ART procedures. However, whether underlying male infertility also increases the risks cannot be excluded.