This is a prospective pilot cohort study of all pregnancies complicated by NIH and severe symmetrical IUGR within the Pediatrix-Obstetrix network. This network encompasses several perinatal sites throughout the United States with corresponding neonatal intensive care units utilizing a computerized patient database (RDS). The objective of this study is to prospectively evaluate amniotic fluid of pregnancies complicated by NIH and severe symmetrical IUGR by a method called tandem mass spectrometry for inborn errors of metabolism.