Utility of Fluorescence In Situ Hybridization as a Fetal Surgery Eligibility Criterion for....

Lizzy Lee from Cincinnati Children's discusses a pertinent study on the utility of invasive genetic testing, specifically Fluorescence In Situ Hybridization (FISH), prior to fetal surgery. The research questions whether FISH provides additional actionable information when non-invasive screening methods like ultrasounds and cell-free DNA already indicate a low risk for aneuploidy. The findings suggest that for carefully selected low-risk pregnancies, non-invasive screening may be sufficient, potentially avoiding the FISH procedure. Ethan Lorence, Katelyn Seither, Hua He, Kara B Markham, Beatrix Wong 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.