Patients were enrolled into the FASTER trial at 10 3/7 to 13 6/7 weeks of gestation, at which time baseline demographic data and medical histories were recorded. Postdelivery follow-up was performed by telephone interview, personal interview, or medical record review by a trained research coordinator at each site. A purpose-designed computerized tracking system with up to 10 contacts per subject was used to ensure optimal outcome collection for all enrolled patients. In addition, a single perinatologist and a pediatric geneticist reviewed detailed maternal and pediatric medical records for the following patient subsets: all patients with abnormal first or second trimester screening, all pregnancies with adverse pediatric outcome, and 10% of normal subjects randomly selected at each site from the trial database.