Maternal Coronavirus Disease 2019 Test Positivity and Neonatal Intensive Care Unit Outcomes for Infants Born Extremely Preterm.

OBJECTIVE

To describe the neonatal intensive care unit outcomes of infants born extremely preterm to mothers who test positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during pregnancy.

STUDY

DESIGN

Prospective study (March 1, 2020-April 30, 2023) at 16 Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network centers of inborn infants (birth weight 401-1000 g and/or gestational age <29 weeks) born to mothers tested for SARS-CoV-2 during pregnancy. Frequency of maternal SARS-CoV-2 detection, vertical transmission rate, and association of maternal SARS-CoV-2 positivity during pregnancy with infant outcomes were determined.

RESULTS

During the 38-month study, 4548 extremely preterm infants were born to 4072 mothers tested for SARS-CoV-2 during pregnancy. Overall, 7% (297/4072) of mothers had a positive SARS-CoV-2 test; 1% (2/181) of tested infants were positive at age <72 hours. The majority of outcomes (eg, bronchopulmonary dysplasia and retinopathy of prematurity) did not differ between infants of test-positive vs test-negative mothers. Infants of test-positive mothers were more likely to be diagnosed with necrotizing enterocolitis (NEC) than those of test-negative mothers (14% vs 11%; P = .03). In adjusted analyses, infants born to test-positive mothers were more likely to develop NEC (risk ratio [RR] 1.40; 95% CI, 1.03-1.89; P = .03) or the combined outcome of death within 12 hours of age or NEC (RR 1.33; 95% CI, 1.09-1.62; P < .01) but not death within 12 hours of age (RR 1.22, 95% CI, 0.92-1.62; P = .16) or before discharge (RR 0.83, 95% CI, 0.55-1.26; P = .38).

CONCLUSIONS

Among infants <29 weeks' gestation, vertical transmission of SARS-CoV-2 was infrequent. Maternal SARS-CoV-2 positivity was associated with NEC but not with other infant outcomes or mortality.

TRIAL REGISTRATION: ClinicalTrials.gov ID. Generic Database: NCT00063063. https://clinicaltrials.gov/study/NCT00063063.