COVID-19 in Pregnancy with Findings of Reduced Head Circumference: A Retrospective Cohort Study

Objective: We investigated the relationship between trimester-specific SARS-CoV-2 infection and newborn growth metrics. We hypothesize that COVID-19 may result in disproportion between neonatal head measurements and weight without increasing the risk of SGA, and that this relationship may be associated with timing of COVID-19 exposure in pregnancy. Design: Retrospective cohort Setting: Northeast USA academic tertiary hospital Population of sample: COVID-19-infected (n=140) and COVID-19-uninfected (n=136) patients Methods: Inclusion criteria: a) singleton birth between April 28, 2020, and December 31, 2022; and b) maternal COVID-19 infection diagnosed via PCR. Exclusion criteria: < 12 years of age, major fetal anomalies, and fetal loss < 15 weeks. Main Outcomes Measures: Outcomes were a comparison of newborn growth measurements (length, weight, and head circumference (HC) at birth), Ponderal Index (PI), and development of SGA between SARS-CoV-2-infected and uninfected patients. Maternal and neonatal characteristics were descriptively summarized, and multivariate analyses and linear regression models were performed. Results: Baseline maternal demographics did not significantly differ among the uninfected and infected cohorts. Compared to the uninfected cohort, COVID-19 diagnosed in the third trimester was associated with a lower neonatal HC compared to newborns of uninfected patients (β=-0.38 0.38 SD lower, 95% CI -0.65 to -0.10, p=0.024). There was no significant difference among the cohorts for birth length, weight, or diagnosis of small for gestational age. Conclusion: We found that COVID-19 infection in the third trimester was associated with a lower neonatal head circumference without associated SGA. The cause underlying this association is unknown. Further research to determine the risk of neurotropic fetal infection by SARS-CoV-2, like ZIKA’s effect on the fetal immune system leading to microcephaly, is urgently needed.