Treatment status of extremely premature infants with gestational age < 28 weeks in a Chinese perinatal center from 2010 to 2019.

"Declarations Ethical approvalThe research protocol has been registered in the Chinese Clinical Trial Registration Center (ID: ChiCTR1900025234) and has been ethically reviewed by the Ethics Committee of the Provincial Hospital Affiliated to Shandong First Medical University (LCYJ: No. 2019-132). Informed consent to participate in the study have been obtained from participants’ parent. Conflict of interestNo financial or non-financial benefits have been received or will be received from any party related directly or indirectly to the subject of this article. The authors have no conflict of interest to declare. Conflict of interest No financial or non-financial benefits have been received or will be received from any party related directly or indirectly to the subject of this article. The authors have no conflict of interest to declare."

"Funding This work was supported by the National Assisted Reproductive and Eugenics Engineering Technology Research Center and Key Laboratory of Reproductive Endocrinology Ministry of Education Open Project, 2017.11-2022.10, the Shandong Key Research and Development Project (2018GSF118163), and Shandong Provincial Medical Health Technology Development Project (2017WS009)."

"Declarations: Ethical approvalThe research protocol has been registered in the Chinese Clinical Trial Registration Center (ID: ChiCTR1900025234) and has been ethically reviewed by the Ethics Committee of the Provincial Hospital Affiliated to Shandong First Medical University (LCYJ: No. 2019-132). Informed consent to participate in the study have been obtained from participants’ parent.: Conflict of interestNo financial or non-financial benefits have been received or will be received from any party related directly or indirectly to the subject of this article. The authors have no conflict of interest to declare. Ethical approval: The research protocol has been registered in the Chinese Clinical Trial Registration Center (ID: ChiCTR1900025234) and has been ethically reviewed by the Ethics Committee of the Provincial Hospital Affiliated to Shandong First Medical University (LCYJ: No. 2019-132). Informed consent to participate in the study have been obtained from participants’ parent."