Utility of Fluorescence In Situ Hybridization as a Fetal Surgery Eligibility Criterion for Isolated Congenital Anomalies When Non‐Invasive Screening Is Performed

OBJECTIVE: Current inclusion criteria for fetal surgery at most centers include the absence of multiple major anomalies and a normal chromosome analysis or fluorescence in situ hybridization (FISH) for aneuploidy. We evaluated the concordance of FISH with non-invasive screening methodologies to determine if invasive genetic testing provides additional information on fetal surgery candidacy. METHODS: A retrospective chart review was performed on 963 pregnancies evaluated for fetal surgery at the Cincinnati Children's Hospital Fetal Care Center between July 1, 2018 and July 31, 2023 for genetic testing results, fetal imaging, and surgical candidacy. RESULTS: FISH was concordant with screening results in 100% of pregnancies whose imaging and cell-free fetal DNA screening suggested a fetus at low risk for trisomy 21, trisomy 18, trisomy 13, and sex chromosome aneuploidies. Pregnancies with multiple congenital anomalies were significantly more likely to have abnormal genetic testing compared to pregnancies with isolated anomalies (52% vs. 17%, P = 0.0009). CONCLUSIONS: In this study cohort, FISH did not provide additional information for the risk-benefit analysis of fetal surgery and introduced additional risk to the pregnancy due to the need for invasive fetal DNA collection.