Celocentesis for Prenatal Diagnosis of Rare Monogenic Diseases: Development, Validation, and Clinical Outcome on 876 Cases

OBJECTIVE: To report on the development, validation, and clinical outcomes of 876 consecutive cases of prenatal diagnosis of rare monogenic diseases using celocentesis. METHODS: This retrospective single-center study, conducted between April 2006 and December 2025, evaluated celomic fluid collected at 7-9 weeks of gestation from women at risk of carrying fetuses with monogenic diseases. Fetal DNA was obtained by isolating embryo-fetal erythroid precursors. All samples were assessed for the presence of parental molecular defects and maternal cell contamination (MCC). RESULTS: The median gestational age at the time of celocentesis was 8.4 weeks. Successful aspiration of celomic fluid was achieved in 875/876 cases (99.9%). Although MCC was observed in 98.74% of the samples, an initial subset of 19/190 (10%) was found unsuitable for molecular analysis. Subsequently, an optimized molecular workflow was successfully applied to the remaining cohort, achieving a success rate of 98% (671/685 procedures). Results were validated against confirmatory samples from abortive tissue (following VIP), amniotic fluid, or postnatal blood. All cases were correctly classified, demonstrating 100% sensitivity and specificity. CONCLUSION: This study supports the clinical application of celocentesis as a reliable early prenatal diagnostic procedure for monogenic diseases. It represents a viable alternative to Chorionic Villus Sampling (CVS) and amniocentesis, enabling invasive prenatal diagnosis at a significantly earlier stage of pregnancy.