Particular aspects of the invention are methods for assaying metabolite levels in samples from a patient during pregnancy using nuclear magnetic resonance and direct flow injection mass spectrometry. In various methods, the assayed metabolites may be acylcarnitine or one or more of C3-OH (hydroxypropionylcarnitine), C5-OH (C3DC), C10, C5:1-DC (glutaconylcarnitine), C14:1-OH (hydroxytetradecenoylcarnitine) and C14:2-OH. One or more methods also may include measuring nuchal translucency of the fetus. Other methods relate to predicting fetal congenital heart defects in a fetus.
