Fetal Surveillance in High-Risk Fetal Cardiac Disease: Frequency, Results and Relationship with Survival.

Objectives: We hypothesized that pregnancies with high-risk fetal heart disease (FHD) would benefit from frequent prenatal surveillance, abnormal fetal surveillance results would be associated with worse outcomes, and cardiovascular profile scoring (CVPS) could identify FHD cases at the highest risk of death.

Methods: A retrospective single-centre study of all actively treated pregnancies with high-risk FHD from 2006-2020. Frequency and results of fetal surveillance, survival, and mode of delivery were collected. Frequent fetal surveillance was defined as ≥ once weekly fetal well-being testing commencing by 28-32 weeks of gestation, or from later diagnosis, until delivery. Where possible, the CVPS was calculated.

Results: Fetal surveillance results were available in 92% (56/61) of pregnancies with high-risk FHD and were abnormal in 18% (10/56). A final CVPS of ≤7 carried a higher mortality (11/21, 52%) than ≥8 (6/31, 19% (P = 0.01)). There was a trend towards worse survival at the last follow-up when fetal surveillance was abnormal versus normal (40%, 4/10 vs. 72%, 33/46, P = 0.07). Survival did not differ between frequent versus infrequent surveillance (13%, 4/30 vs. 3%, 1/31, P = 0.20); nor when comparing abnormal versus normal surveillance results (20%, 2/10 vs. 7%, 3/46, P = 0.21). Where fetal surveillance was abnormal, emergency cesarean delivery was more common (70%, 7/10 vs. 4%, 2/46, P < 0.001).

Conclusions: Abnormal fetal surveillance results and/or a CVPS ≤7 may identify compromised fetuses with high-risk FHD who could benefit from altered management or expedited delivery. Given the high rates of abnormal fetal surveillance in high-risk FHD, frequent fetal surveillance in the third trimester should be considered.