Contributions to Authorship
The version to be published was approved by all the authors.all authors
agree to be accountable for all aspects of the work in ensuring that
questions related to the accuracy or integrity of any part of the work
are appropriately investigated and resolved.
Author Jing Wu was responsible for research design and management.
Author Qian Liu was responsible for case collection, data analysis, and
article writing. Author Xiaomei Shi, Liyuan Fang and Tengzi Rao were
responsible for case collection. Author Lishuang Shi was responsible for
follow-up work of all cases .
Details of Ethics Aprroval
All pregnant women rolled in the study have given their written informed
consent and that the study protocol was approved by the Guangdong Women
and Children Hospital Medical Ethics Committee on October 19,2017. The
Ethics Review Resolution Number is 20171048.