1. Department of Obstetrics and Gynecology, Oregon Health and Science University, Portland, OR, USA,
2. School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA
3. Department of Obstetrics and Gynecology, University of California, Irvine, CA, USA
4. Department of Obstetrics and Gynecology, Oregon Health and Science University, Portland, OR, USA