Correction to: BMC Pregnancy Childbirth 21, 784 (2021)

https://doi.org/10.1186/s12884-021-04237-y

Following publication of the original article [1], the authors identified an error in the affiliation of Xiang Kong.

The incorrect affiliation is: Department of Obstetrics and Gynecology, Subei People’s Hospital, Yangzhou, Jiangsu Province, China.

The correct affiliation is: Department of Obstetrics and Gynecology, Medical College of Yangzhou University, Yangzhou, Jiangsu Province, China.

The original article has been corrected.