*Correspondence author:
1.Zhiwei Liu MD, PhD, Department of Neonatology, International Peace Maternity and Child Health Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Embryo Original Disease, Shanghai Municipal Key Clinical Specialty, Huashan Rd. 1961 Shanghai, 200030, China; Tel: +86 21 64070434. Fax: +86 21 64474645. Email: liuzhiwei@hotmail.com.
2.Fang Chen, MD, PhD.Department of Urology, Shanghai Children’s Hospital, Shanghai Jiao TongUniversity, 355 Luding Road, Shanghai, 200062, China; Department of Urology, Shanghai Sixth People’s Hospital, Shanghai JiaoTong University, 600 Yishan Road, Shanghai, China;Shanghai Eastern Institute of Urologic Reconstruction.E-mail: doctorchenfang@126.com.
Funding : This work was supported by the National Key Research and Development Program of China (2016YFC1000203), the National Natural Science Foundation of China Grants (81974232),and the Shanghai Municipal Commission of Health and Family Planning (2016ZB0102-02).
Acknowledgements: The authors thank the participating parturients and their infants.
Ethics approval: Ethics approval and use of clinical data for research purposes was granted by the Ethics Committees of the International Peace Maternity and Child Health Hospital (GKLW 2017-101) in 23rd August 2018.
Conflict of Interest: The authors declare that they have no competing interests.