A Pilot Randomized Controlled Trial of Maternal Oxygen Therapy for Fetal Left Heart Hypoplasia
The purpose of this study is to determine if maternal hyperoxygenation is an effective treatment for fetal left heart hypoplasia versus room air (placebo). This will be determined by measuring how well a baby's heart valves and their surrounding tissue are growing and functioning. In addition the investigators will examine brain growth using fetal ultrasound and MRI, and MRI of the child's brain after they are born to determine if there is greater neonatal brain maturity or mothers receiving oxygen compared to fetuses of mothers not receiving oxygen. Of note, the trial was initially randomized. However, due to low sample size and hesitation about randomization, the trial was converted to an open label study, allowing families opting for oxygen therapy to be in the intervention arm.
• Mothers carrying fetuses with small left sided structures likely needing neonatal intervention, defined as the following on fetal echocardiography:
• Sum of aortic and mitral valve z-scores (standard deviation based on gestational age) less than -4.5
• Flow across the atrial septum either bidirectional or left to right
• Transverse aortic arch or isthmus z-score less than 2.0.