Maternal Hyperoxygenation in Congenital Heart Disease (MATCH)

A pilot study investigating the safety and feasibility of chronic maternal hyperoxygenation in the setting of fetal congenital heart disease

The aim of the study is to investigate the safety and feasibility of chronic maternal hyperoxygenation in pregnancies affected by fetal congenital heart disease, specifically those pregnancies in which the fetus has single ventricle physiology with aortic arch obstruction. The treatment has a potentially neuroprotective effect on the fetus. This would be desirable as the neurodevelopmental outcomes of the survivors of this form of congenital heart disease are significantly below normal. However, transplacental oxygen has not been tried in this setting, and so before embarking on a trial, the investigators need to establish that the treatment is safe and feasible. This will be accomplished by recruiting subjects which meet the eligibility criteria and commence treatment at the time of diagnosis, usually in the second trimester, and by comparing outcomes with a historical cohort with CHD diagnoses with no oxygen intervention. The oxygen will be delivered to the mother via nasal prongs continuously at a rate of up to 4 L/min. Oxygen concentrators will be supplied to the subjects' homes, and a range of portable devices will also be provided to allow them to continue with usual activities of daily living. A series of follow up appointments will be arranged to check the status of the mother and fetus. Mothers will be invited to keep a diary of their adherence to the treatment. A range of routine clinical and research data on the condition of the fetus and newborn will be collected.

Oxygen via nasal prongs at up to 4L/min continuously during 2nd and 3rd trimester of pregnancy until birth

The general condition of the child and mother at birth, classified by any maternal or fetal adverse events. Adverse events will also be classified as mild, moderate, severe, life-threatening or disabling, or fatal. The investigators will further define adverse events in terms of their effect on usual daily activities as follows: mild (an awareness of symptoms but easily tolerated), moderate (symptoms interfere with normal daily activities) or severe (symptoms are incapacitating, with the inability to perform daily activities). As unexpected adverse effects are by definition difficult to predict, the investigators use a variety of sources of information to identify possible side effects of the treatment including participant diaries, direct observations, participant reports, laboratory reports and other medical reports.

This will be as a proportion of the maximum potential duration if the subjects had adhered to the continuous therapy from enrollment to birth. If the treatment is not tolerable by a substantial number (e.g. >10%) of subjects for significant periods of time (e.g. more than 8 hours a day) in the pilot study then this will be considered a negative result, i.e. that the treatment is not feasible.

Inclusion Criteria: Between 20-32 weeks gestation Diagnosis of fetus with a single ventricular ventricular heart Delivering at Mount Sinai Hospital Written informed consent Exclusion Criteria: Opting for termination of pregnancy/ comfort care Normal exclusions for MRI (e.g. claustrophobia, cardiac pacemaker, etc.) BMI >37.0 Infections/ anemia Smoker Serious cardiorespiratory co-morbidities