Effects of COVID-19 Infection on Fetal Growth in Pregnancy

Background: Infections are known to affect fetal development and growth. Studies have shown that there is a higher frequency of maternal vascular malperfusion in the placental bed in pregnant women infected with COVID-19. It is further suggested that the abovementioned changes seen in the placentas of women infected with COVID-19 is associated with significant clinical sequelae, such as, preterm birth, fetal growth restriction (FGR), and fetal demise. Although there are growing studies that have evaluated the impact of COVID-19 infection on fetal growth, data remains limited. As a result, there is little consensus on perinatal recommendations and counseling that should be given to women infected patients COVID-19 during pregnancy. During the COVID-19 pandemic, our Maternal Fetal Medicine Clinics opted to perform serial growth ultrasounds and additional antenatal testing in the third trimester in women infected with the disease. Whether performance of these ultrasounds identified cases of fetal growth restriction and impacted fetal outcomes remains unknown. The purpose of this study is to perform a retrospective review of all ultrasounds performed in women identified to have COVID-19 during June 2020-December 2022, and to evaluate the impact on fetal growth. We hypothesize that COVID-19 will increase the risk of fetal growth restriction compared to pregnant women without COVID-19. Study Design: This is a retrospective cohort study within the Obstetrix Maternal-Fetal Medicine Specialist of Houston Clinics. The study included all patients aged 16-55 years old with a singleton pregnancy who received an ultrasound at Obstetrix Maternal-Fetal Medicine Specialist of Houston between June 2020-December 2022. COVID-19 infection during pregnancy was defined as a self-reported positive SARS-Co-2 RT-PCR or Rapid Test. FGR was defined as estimated fetal weight less than the 10% or abdominal circumference less than the 10% for gestational age. Maternal and fetal characteristics, including FGR, were collected and compared between the two groups. Results: Among the 21,917 women with a singleton pregnancy who received an ultrasound at Obstetrix Maternal-Fetal Medicine Specialist of Houston between June 2020-December 2022, 484 (2%) had COVID-19 infection during pregnancy and 21,433 (98%) did not. Of those who had COVID-19 infection during pregnancy there were 45 (9%) cases of FGR, and when compared to pregnant individuals reporting negative for COVID-19 there were 2,928 (14%) cases of FGR, p=005. When the 484 women who had COVID-19 were stratified by the timing of their COVID-19 infection by first, second and third trimester, there was no significant difference in the proportion who had an offspring with FGR (p=0.33 Cochran-Armitage test for trend). Conclusion: COVID-19 infection in pregnancy, when compared to those who do not have COVID-19 infection in pregnancy does not appear to be more associated with FGR. The performance of routine serial fetal growth ultrasounds may not be indicated in pregnant women solely for the purpose of having a history of a COVID-19 infection during pregnancy.