Rates of Fetal Growth Restriction and Small for Gestational Age Neonates by COVID-19 Epochs: Did the Pandemic Affect Fetal Biometry Measurements?

This study aimed to examine rates of fetal growth restriction (FGR) and small for gestational age (SGA) neonates before, during, and after the COVID-19 pandemic. We retrospectively evaluated patients with singleton deliveries ≥ 22 weeks of gestation in a single hospital system from March 2018 to December 2022. Patients were assigned to one of three COVID-19 epochs: acute-COVID-19, based on gestational age < 20 weeks on February 3, 2020, and estimated due date before January 1, 2021; pre-COVID-19 and postacute-COVID-19 epochs consisted of patients with matched months 2 years before and after the acute-COVID-19 epoch. Outcomes were FGR and SGA; FGR was defined by International Classification of Diseases-10 codes, and SGA was defined by birthweight < 10th percentile, using the Aris distribution for gestational age and neonatal sex. Patient attributes were compared across COVID-19 epochs, FGR, and SGA separately, using chi-square tests or ANOVA, as appropriate. Crude and adjusted logistic regression models were performed, including covariates associated with each dependent variable. A total of 9,692 patients were included; differences across COVID-19 epochs were observed for advanced maternal age, body mass index ≥ 30 at delivery, smoking, chronic hypertension, hypertensive disorders of pregnancy, number of prenatal care visits, and ultrasounds. Patients in the acute- and post-COVID-19 epochs had an increased odds of FGR (aOR: 1.76, 95% CI: 1.44-2.16 and aOR: 1.64, CI: 1.38-1.94, respectively) compared with the pre-COVID-19 epoch. Compared with the pre-COVID-19 epoch, patients in the acute-COVID-19 epoch had reduced odds of SGA (aOR: 0.80, 95% CI: 0.65-0.98). During the acute-COVID-19 epoch, FGR diagnosis increased compared with pre-COVID-19, while SGA at birth decreased. This highlights the limitation of prenatal ultrasound for precisely identifying fetuses at the highest risk of FGR, which may be due to confirmation bias or broad diagnostic criteria for FGR. · We found no significant difference in the number of prenatal visits across COVID-19 epochs.. · The rate of FGR increased during the acute-COVID-19 epoch, while the rate of SGA decreased.. · Incongruence of FGR and SGA rates highlights the limitation of ultrasound to precisely identify at-risk fetuses..