Infertility treatment-conceived pregnancies at risk of neonatal mortality

Pregnancies that resulted from infertility treatment show a heightened risk of neonatal mortality, with this association largely mediated through preterm delivery, a study has found.

The analysis involved a total of 14,961,207 pregnancies resulting in a singleton live birth, of which 198,986 (1.3 percent) were conceived following any infertility treatment (eg, assisted reproductive technology and fertility-enhancing drugs).

The primary outcome was death within the first 27 days of life (neonatal mortality <28 days). Researchers performed a causal mediation analysis of the association between infertility treatment and mortality in relation with preterm delivery (<37 weeks).

In log-linear Poisson models, infertility treatment conferred a 51-percent higher risk of neonatal mortality (risk ratio [RR], 1.51, 95 percent confidence interval [CI], 1.39–1.64), with the risk of early neonatal mortality (RR, 1.57, 95 percent CI, 1.43–1.73) slightly higher than late neonatal mortality (RR, 1.33, 95 percent CI, 1.11–1.58). These risks were similar for pregnancies conceived through assisted reproductive technology and fertility-enhancing drugs.

The mediation analysis showed that preterm delivery mediated 72 percent (95 percent CI, 59–85) of the total effect of infertility treatment on neonatal mortality.

A sensitivity analysis that corrected for exposure misclassification and unmeasured confounding biases confirmed that the risks were higher for early, but not for late, neonatal mortality.

Researchers advised caution when interpreting the findings given the substantial underreporting of infertility treatment.