Ethics approval and consent to participate
Ethical clearance was obtained from the ethical committee of The First Affiliated Hospital of Wenzhou Medical University on 29/09/2021 (Chairperson Pro. Jinglin Xia, NO.KY2021-119) and registered at chictr.org.cn (ChiCTR2100053635) on 26/11/2021. The study was conducted according to the criteria of Declaration of Helsinki, and informed consent was obtained from each included parturient.