Fetal Electrophysiologic Abnormalities in High-Risk Pregnancies Associated With Fetal Demise

Inclusion Criteria: * Current pregnancy complicated by one of the five diagnostic categories * prior unexplained Stillbirth at/after 20 weeks gestation * fetal major congenital heart defect * fetal hydrops * fetal gastroschisis * monochorionic twin pregnancy * Subject must be 18 years of age or older * Subject must be English speaking and must be able to read and sign the consent form in English * Subject must be able to recline comfortably for 1-3 hours * Subject must be willing to complete all three procedures (fMCG, fMCG, nECG) as per protocol, unless medically unable * Subject must be willing to allow us to review her and her infants prenatal, deliver, and post-natal records to verify diagnosis, and clinical findings. Exclusion Criteria: * Severe claustrophobia not reduced by taking breaks, or by having the light on, or by having someone in the room with them. * Active labor * Acute illness * Unable to recline comfortably with a pillow for more than 1-3 hours (assuming some breaks are provided) * Weight over 450 lbs * An electric stimulation device (TENS unit, pacemaker, or nerve stimulator) that could produce electric or magnetic noise. * Note that the Tristan 624 Magnetometer does not pose a risk to the subject's device, (since fMCG does not produce any energy or magnetism), but stimulators themselves can cause interference for our recordings. Some devices may still qualify, and discussion with study nurse may be useful if subject has a pacemaker or similar device. The subject will have a single 2-3 hour fetal magnetocardiogram at approximately 20 and 27 weeks GA, and again, if medical condition allows, between 30 and 37 weeks GA, then her infant will have an ECG between 0 and 4 weeks of age. Subjects will be paid a nominal fee for their participation each time, as well as transportation reimbursement if \>25 miles. For subjects traveling a long distance, the ECG may be performed locally or at home.