Outcomes of Very Preterm Infants Conceived with Assisted Reproductive Technologies

The effect of fertility treatment and socioeconomic status on neonatal and post-neonatal mortality in the United States

OBJECTIVE

To determine the association between fertility treatment, socioeconomic status (SES), and neonatal and post-neonatal mortality.

STUDY DESIGN

Retrospective cohort study of all births (19,350,344) and infant deaths from 2014-2018 in the United States. The exposure was mode of conception-spontaneous vs fertility treatment. The outcome was neonatal (<28d), and post-neonatal (28d-1y) mortality. Multivariable logistic models were stratified by SES.

RESULT

The fertility treatment group had statistically significantly higher odds of neonatal mortality (high SES OR 1.59; CI [1.5, 1.68], low SES OR 2.11; CI [1.79, 2.48]) and lower odds of post-neonatal mortality (high SES OR 0.87, CI [0.76, 0.996], low SES OR 0.6, CI [0.38, 0.95]). SES significantly modified the effect of ART/NIFT on neonatal and post-neonatal mortality.

CONCLUSIONS

Fertility treatment is associated with higher neonatal and lower post-neonatal mortality and SES modifies this effect. Socioeconomic policies and support for vulnerable families may help reduce rates of infant mortality.

Fertility treatment increases the risk of preterm birth independent of multiple gestations

Objective

To investigate the complex interplay between fertility treatment, multiple gestations, and prematurity.

Design

Retrospective cohort study linking the national Center for Disease Control and Prevention infant birth and death data from 2014 to 2018.

Setting

National database from Center of Disease Control and Prevention.

Patients

In total, 19,454,155 live-born infants with gestational ages 22-44 weeks, 114,645 infants born using non IVF fertility treatment (NIFT), and 179,960 via assisted reproductive technology (ART).

Intervention

Noninvasive fertility treatment or ART vs. spontaneously conceived pregnancies.

Main Outcome Measures

The main outcome assessed was prematurity. Formal mediation analysis was conducted to calculate the percentage mediated by multiple gestations.

Results

Newborns born using NIFT or ART compared with those with no fertility treatment had a higher incidence of multiple gestation (no fertility treatment = 3.0%; NIFT = 24.7%; ART = 32.7%; P<.001) and prematurity (no fertility treatment = 11.2%; NIFT = 23.4%; ART = 28.4%; P<.001). Mediation analysis demonstrates that 76.8% (95% confidence interval [CI], 75.2%-78.1%) of the effect of NIFT on prematurity was mediated through multiple gestations. Similarly, 71.2% (95% CI, 70.8%-72.7%) of the effect of ART on prematurity is mediated through multiple gestation. However, the direct effect of NIFT on prematurity is 20.4% (95% CI, 19.0%-22.0%). The direct effect of ART was 24.7% (95% CI, 23.7%-25.6%).

Conclusion

A significant proportion of prematurity associated with fertility treatment is mediated by the treatment itself, independent of multiple gestations.