Contribution to authorship
MW, HC and GQX conceived the study. WM drafted the manuscript and contributed to data acquisition, analysis, and interpretation. HC and GQX obtaining written consent from patients, obtaining ethical approval, and participated in revising the final manuscript. XZZ, JWZ and LC were the obstetricians of the pregnant women, and took responsibility for collecting samples, and confirming data accuracy. LX, DJY,QMZ and QQT were in charge of following up the mothers and the babies and collecting the followed-up materials. QQL and HAK were in charge of the laboratory tasks, including sample processing and detection.