1. Department of Obstetrics & Gynecology, Division of Maternal Fetal Medicine, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA
2. Institute for Environmental Health Solutions, Gillings School of Global Public Health, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA
3. Department of Environmental Sciences & Engineering, Gillings School of Global Public Health, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA