Inclusion Criteria:  Singleton gestation Qualify for a first-trimester screen at the time of enrollment. Criteria for the screen include pregnancy with gestational age between 10 weeks 3 days and 13 weeks 6 days of gestation as well as a crown-rump length between 40 and 84 mm. Complete a first-trimester ultrasound at the qualifying M Health Fairview Maternal Fetal Medicine Clinics, which include University Riverside, Ridges, South Dale, and Health East sites Provide a blood sample for either completion of the first-trimester screen and/or for the completion of the research study  Exclusion Criteria:  Multi-fetal gestation or pregnancy with major fetal congenital anomalies and/or known fetal aneuploidy Unwilling to complete a first-trimester ultrasound and/or unwilling to provide a serum sample