Investigating Perinatal Outcomes during the Low Prevalence First Year of Covid-19 in a Multiethnic Australian Population

Abstract

Background: Little information is available on the impact of the COVID-19 pandemic on perinatal outcomes in an Australian high-migrant and low COVID-19 prevalent population. Method(s): Retrospective cohort study of singleton births in an ethnically diverse population, Western Sydney, Australia before and during the first low prevalence year of the COVID-19 pandemic. Pre COVID-19 defined as 1st January 2018-31st January 2020, and global COVID-19 period 1st February 2020-31st January 2021. Multivariate logistic regression analysis was conducted adjusting for confounders including age, socioeconomic status, gestational age, parity, ethnicity, and BMI. Result(s): 34,103 births met inclusion criteria for the study period; pre-COVID-19 n = 23,722; during COVID-19 n = 10,381. During the first year of COVID-19 there was a higher rate of complication of composite hypertensive disorders/gestational diabetes (aOR 1.07 95%CI 1.01-1.14) and a 19% reduction in vaginal births (aOR 0.81; 95%CI 0.77-0.86). However, during the COVID-19 period there was a 15% reduction in spontaneous preterm births (aOR 0.85; 95%CI 0.75, 0.97) but no change for iatrogenic preterm births (aOR 0.94; 95%CI 0.80, 1.09). We also found a 10% reduction in small for gestational age infants at birth (aOR 0.90; 95% CI 0.82-0.99). Full breastfeeding rates at hospital discharge reduced by 15% during the COVID-19 period (aOR 0.85; 95%CI 0.80-0.90). Conclusion(s): Despite a low prevalence of COVID-19 during the study period, adverse obstetric outcomes were observed which may have been related to changes in service delivery and interaction with health services. Further research is suggested to understand drivers for adverse and positive obstetric changes in this population.