Transcervical, Transabdominal and Transvaginal Chorionic Villus Sampling for Prenatal Diagnosis in Zagreb, Croatia: A Prospective Single-Operator Study on 5500 Cases

Background/Objectives: Chorionic villus sampling (CVS) is a pivotal diagnostic tool for early prenatal detection of chromosomal and genetic abnormalities; however, the safety and diagnostic efficacy of different CVS approaches remain a subject of clinical interest. This monocentric study compares transcervical (TC-CVS), transabdominal (TA-CVS) and transvaginal (TV-CVS) techniques, focusing on procedure-related fetal loss and diagnostic yield. Methods: In this 15-year, single-operator prospective study, a total of 5500 women underwent CVS between 10 and 14 weeks of gestation at a single center. Sampling was performed via TA-CVS (n = 4500), TC-CVS (n = 850), or TV-CVS (n = 150). Outcomes assessed included fetal loss rates, sample adequacy, early complications and hemodynamic changes measured by Doppler ultrasound. A p-value < 0.05 (two-tailed) was considered statistically significant. Results: Spontaneous abortion rates were significantly lower following TA-CVS (0.18%; 8/4500) compared to TC-CVS (0.6%; 5/850) and TV-CVS (1.3%; 2/150) (χ2 = 24.56, p < 0.001). Post hoc pairwise analysis showed significantly lower fetal loss in TA-CVS compared to TC-CVS, but not between TA-CVS and TV-CVS. Cytogenetic abnormalities were detected in 220 cases (4.0%), and clinically significant copy number variants (CNVs) were confirmed in fetuses with major structural malformations. Five-year follow-up showed no diagnosed intellectual disability among assessed children. Optimal tissue weight (10–20 mg) was more frequent with TA-CVS (66.7%) than TC-CVS (35.3%) or TV-CVS (36.7%) (χ2 = 350.92, p < 0.001). In a Doppler subset (n = 400), uterine, spiral, and interplacental artery PI changes were non-significant; the umbilical (p = 0.032) and middle cerebral arteries (p < 0.001) showed transient PI reductions after sampling. Conclusions: Transabdominal CVS demonstrated the most favorable balance of safety and diagnostic quality, suggesting it should be the preferred first-line technique in early prenatal diagnosis. Standardized technique and operator training remain critical to optimize outcomes.