作者单位:Perinatology Research Branch, NICHD/NIH/DHHS, Detroit, MI, United States, Perinatology Research[1]Perinatology Research Branch, NICHD/NIH/DHHS, Detroit, MI, United States, Department of Obstetrics[2]Perinatology Research Branch, NICHD/NIH/DHHS, Detroit, MI, United States[3]