Maternal hyperoxygenation in prenatal ultrasound and fetal echocardiography – literature review 2020

Twenty-nine publications about maternal hyperoxygenation (MHO) were reviewed: 20 discussing MHO as a diagnostic test used by obstetricians (in SGA/IUGR, preeclampsia, fetuses with diaphragmatic hernia, healthy fetuses) and fetal cardiologists (in HLHS, Ebstein, lung hypoplasia, diaphragmatic hernia). Maternal hyperoxygenation was used for 8-20 min, and out of 13 obstetrical publications 8 provided positive effects for stratification of perinatal management. Seven of the fetal cardiology publications were positive. Nine publications dealing with MHO as a transplacental treatment presented positive results in 7, in 1 there was suggestion for necessity for postnatal follow-up with head circumference measurements during postnatal life, and 1 paper (review) suggested that MHO should be curtailed.

Based on the current literature, it can be concluded that MHO has no harmful effect when used in the short term for testing. Longer paediatric and neurological follow-up is needed when used chronically as a fetal therapy. Institutional Review Board approval is recommended as well as informed consent.

Maternal hyperoxygenation as a test might be a useful for testing the fetal circulation, and it gives insight into fetal CV physiology and during transition and might be helpful for the better stratification for perinatal care in fetuses with selected heart defects.

Assessment of blood flow and cardiovascular status during MHO by fetal echocardiography in the 3rd trimester is challenging and requires a high level of expertise. Optimally it should be performed in fetal cardiac centres.