1. Department of Obstetrics and Gynecology Division of Maternal‐Fetal Medicine Keck School of Medicine University of Southern California Los Angeles California USA
2. Childbirth Research Associates, LLC North Hollywood California USA
3. Department of Obstetrics and Gynecology Division of Maternal Fetal‐Medicine Cedars‐Sinai Medical Center Los Angeles California USA
4. Department of Obstetrics and Gynecology Division of Maternal‐Fetal Medicine David Geffen School of Medicine University of California Los Angeles Los Angeles California USA
5. Department of Obstetrics and Gynecology Division of Maternal‐Fetal Medicine Loma Linda University Loma Linda California USA