Can prenatal ultrasound predict adverse neonatal outcomes in SARS-CoV-2-affected pregnancies?

Abstract

Background: On the basis of available data, at least 1 ultrasound assessment of pregnancies recovering from SARS-CoV-2 infection is recommended. However, reports on prenatal imaging findings and potential associations with neonatal outcomes following SARS-CoV-2 infection in pregnancy have been inconclusive.

Objective: This study aimed to describe the sonographic characteristics of pregnancies after confirmed SARS-CoV-2 infection and assess the association of prenatal ultrasound findings with adverse neonatal outcomes.

Study design: This was an observational prospective cohort study of pregnancies diagnosed with SARS-CoV-2 by reverse transcription polymerase chain reaction between March 2020 and May 2021. Prenatal ultrasound evaluation was performed at least once after diagnosis of infection, with the following parameters measured: standard fetal biometric measurements, umbilical and middle cerebral artery Dopplers, placental thickness, amniotic fluid volume, and anatomic survey for infection-associated findings. The primary outcome was the composite adverse neonatal outcome, defined as ≥1 of the following: preterm birth, neonatal intensive care unit admission, small for gestational age, respiratory distress, intrauterine fetal demise, neonatal demise, or other neonatal complications. Secondary outcomes were sonographic findings stratified by trimester of infection and severity of SARS-CoV-2 infection. Prenatal ultrasound findings were compared with neonatal outcomes, severity of infection, and trimester of infection.

Results: A total of 103 SARS-CoV-2-affected mother-infant pairs with prenatal ultrasound evaluation were identified; 3 cases were excluded because of known major fetal anomalies. Of the 100 included cases, neonatal outcomes were available in 92 pregnancies (97 infants); of these, 28 (29%) had the composite adverse neonatal outcome, and 23 (23%) had at least 1 abnormal prenatal ultrasound finding. The most common abnormalities seen on ultrasound were placentomegaly (11/23; 47.8%) and fetal growth restriction (8/23; 34.8%). The latter was associated with a higher rate of the composite adverse neonatal outcome (25% vs 1.5%; adjusted odds ratio, 22.67; 95% confidence interval, 2.63-194.91; P<.001), even when small for gestational age was removed from this composite outcome. The Cochran Mantel-Haenszel test controlling for possible fetal growth restriction confounders continued to show this association (relative risk, 3.7; 95% confidence interval, 2.6-5.9; P<.001). Median estimated fetal weight and birthweight were lower in patients with the composite adverse neonatal outcome (P<.001). Infection in the third trimester was associated with lower median percentile of estimated fetal weight (P=.019). An association between placentomegaly and third-trimester SARS-CoV-2 infection was noted (P=.045).

Conclusion: In our study of SARS-CoV-2-affected maternal-infant pairs, rates of fetal growth restriction were comparable to those found in the general population. However, composite adverse neonatal outcome rates were high. Pregnancies with fetal growth restriction after SARS-CoV-2 infection were associated with an increased risk for the adverse neonatal outcome and may require close surveillance.

Keywords: SARS-CoV-2 infection; adverse neonatal outcome; fetal growth restriction; pregnancy; ultrasound.

Figure 1

Flow diagram of ultrasound results.