Associations of COVID-19 Pandemic with Clinical Manifestations Among the Uninfected Pregnant Women in China: A Combined Cohort Study

Background: Whether coronavirus disease 2019 (COVID-19) pandemic would affect pregnancy-associated factors of uninfected pregnant women was rarely reported. Methods: A total of 32,277 pregnant women from six sites (Hubei Province, Guangdong Province, Hebei Province, Shandong Province, Yunnan Province and Beijing City) were finally recruited. We conducted a retrospective combined cohort study to analyze the associations between the number of prenatal examinations (NPE), delivery gestational week (DGW), the risk of caesarean section (CS), stillbirth, neonatal weight, preterm birth, macrosomia, small for gestational age (SGA), large for gestational age (LGA) and the COVID-19 in two time-periods, the pre-pandemic period (P-2019, 1/1/19-5/31/19) and the pandemic period (P-2020, 1/1/20-5/31/20). Findings: After adjusting for other covariates, we found the NPE, DGW, and SGA were negatively associated with the COVID-19 pandemic, whereas the CS and preterm birth rates were positively associated with the COVID-19, with adjusted relative risks (aRRs) of 1.11 [95% confidence interval (CI) 1.06–1.17] and 1.37 (95% CI: 1.02–1.84) respectively in Hubei. For Guangdong, the associations of CS and preterm birth with the COVID-19 were similar in Hubei. In contrast, limited associations were evident in other areas, except for a positive association with macrosomia [aRR = 1.26 (95% CI: 1.03–1.55)] in Beijing. Interpretation: The CS and preterm birth rates increased slightly in areas that were more affected by the pandemic than other areas among uninfected pregnant women. NPEs were not significantly interrupted and most maternal and neonatal clinical characteristics were within the normal ranges. Funding: National Key Research and Development Program, National Natural Science Foundation of China and National Health Commission Capacity Building and Continuing Education Center. Declaration of Interests: All authors declare to have no conflict of interest. Ethics Approval Statement: The study was approved by the Peking University ethics board (no. IRB00001052-20025).