Spectrum of Chromosomal Abnormalities in Abortus and Medically Terminated Fetal Samples From a Tertiary Care Center in the Sub-Himalayan Region of North India

Background: Chromosomal abnormalities are a major cause of spontaneous abortions and medically terminated pregnancies. Molecular characterization of abortus tissue plays a critical role in establishing etiological diagnosis, enabling accurate genetic counselling and recurrence risk assessment. However, region-specific molecular data from the sub-Himalayan population remain limited. Objective: To evaluate the spectrum and frequency of chromosomal abnormalities in spontaneous abortus and medically terminated fetal samples using molecular genetic techniques at a tertiary care center in North India. Methodology: This cross-sectional observational study included 39 fetal samples obtained following spontaneous abortion or medically indicated termination of pregnancy between August 2022 and February 2026 at a tertiary care referral center serving the sub-Himalayan region of North India. Following detailed gross examination and dissection, genomic DNA was extracted from fetal tissue and analyzed using the Devyser Extended Aneuploidy quantitative fluorescence polymerase chain reaction (QF-PCR) assay targeting chromosomes 13, 15, 16, 18, 21, X, and Y. The samples underwent additional evaluation using Sanger sequencing for confirmation and further characterization of detected chromosomal abnormalities. Molecular findings were correlated with clinical characteristics and prenatal imaging data. Results: Chromosomal abnormalities were identified in 10 of 39 cases (25.6%). Trisomy 21 was the most frequently detected abnormality (7, 17.9%), followed by trisomy 18 (1, 2.6%). Trisomy 22 was identified in one case (2.6%) and monosomy X in one case (2.6%). Central nervous system anomalies constituted the most common structural abnormalities and were frequently observed in fetuses with chromosomal defects. The majority of cases (29, 74.4%) demonstrated a normal euploid genotype, suggesting potential contribution of non-chromosomal or maternal factors. Conclusions: Chromosomal abnormalities contribute significantly to pregnancy loss in this study, with autosomal trisomies representing the predominant genetic findings. QF-PCR provides a rapid and reliable diagnostic approach for detecting common aneuploidies in abortus tissue. Routine incorporation of molecular testing may enhance etiological clarification and improve genetic counselling and reproductive planning in affected couples.