title: Reply.
authors.affiliation: Department of Obstetrics, Gynecology, and Reproductive Sciences, Division of Maternal-Fetal Medicine, University of California, San Francisco, San Francisco, CA. Electronic address: jsperling@wihri.org.
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Sperling
authors.affiliation: Nebraska Methodist Women's Hospital and Perinatal Center, Omaha, NE.
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Dahlke
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Texas Health-University of Texas Medical School at Houston, Houston, TX.
authors.forename: Baha M
authors.initials: BM
authors.lastname: Sibai