*Department of Anesthesiology, Obstetrics and Gynecology Hospital of Fudan University, Shanghai, China

†Division of Epidemiology, Biostatistics, and Environmental Health, School of Public Health, University of Memphis, Memphis, TN

Y.L.: conception and design, drafting the article and revising it critically for important intellectual content. L.Z.: acquisition of data. J.J.: acquisition of data. X.Y.: analysis and interpretation of data. S.H.: conception and design, and final approval of the version to be published. All authors discussed the results and commented on the manuscript. Y.L. and L.Z. contributed equally to this work as first authors.

This manuscript was previously posted to medRxiv: doi: https://doi.org/10.1101/2020.08.19.20177725.

The authors declare no conflicts of interest.

Reprints: Shaoqiang Huang, PhD, 128 Shenyang Road, Shanghai 200090, China (e-mail: [email protected]).