Decreased Newborn Size following COVID-19 Infection during Pregnancy: The Role of Timing of Infection

The objective of this study was to examine the effect of coronavirus disease 2019 (COVID-19) infection during pregnancy on birth outcomes, including the relationship between the trimester of COVID-19 infection and newborn size. Findings could be used to better inform appropriate management of COVID-19 during pregnancy.This retrospective chart review study included patients diagnosed with COVID-19 who received care at a single university-affiliated obstetrics practice. Pregnant patients with a diagnosis of COVID-19 between April 2022 and April 2023 were included in this study. Participant demographics and birth outcomes were extracted and analyzed.Our sample included 141 women who had COVID-19 during pregnancy, grouped based on the trimester of COVID-19 infection. In analyses adjusted for confounding background factors, those with a COVID-19 infection during the second trimester (<i>n</i> = 57) and third trimester (<i>n</i> = 50) had newborns with significantly decreased head circumference at birth compared with those infected during the first trimester (<i>p</i> < 0.05). In addition, compared with those with a COVID-19 infection during the first trimester, those who had COVID-19 during the third trimester had an average 1.3 cm decreased birth length.In the current study, COVID-19 infection later in pregnancy, especially in the third trimester, significantly predicted decreased birth weight, length, and head circumference. · COVID-19 infection may impact newborn size.. · Third-trimester infection was most detrimental.. · Late-term monitoring may be warranted..