Predicting Lethality in Fetal Skeletal Dysplasias: Insights from a 10-Year Study at a Tertiary Care Hospital in Pakistan

Introduction: Skeletal dysplasia comprises a diverse group of genetic disorders affecting bone and cartilage development, with significant perinatal morbidity and mortality. Prenatal diagnosis primarily relies on ultrasound; however, due to the heterogeneity of these disorders, additional genetic testing is often required. Lethality is typically predicted using sonographic markers, including a femur length-to-abdominal circumference ratio of <0.16. This study aims to assess the concordance between prenatal lethality predictors and perinatal outcomes. Methodology: A retrospective study was conducted at Aga Khan University Hospital from January 2012 to December 2022, including all pregnancies diagnosed with fetal skeletal dysplasia via ultrasound. Demographic, clinical, and neonatal data were extracted from hospital records. Lethality was suspected based on ultrasound markers, and pregnancy outcomes were analyzed. Termination of pregnancy was offered before 24 weeks. Genetic testing was performed in selected cases. Results: A total of 23 cases met the inclusion criteria. The mean maternal age was 27.7 ± 5.9 years, with consanguinity noted in 47.8% of cases. Diagnosis was made before 24 weeks in 56% of cases, with elective termination in 69% of these pregnancies. Among the 12 live births, five survived the neonatal period. Prenatal lethality prediction was made in seven cases, with four elective terminations, one stillbirth, and two neonatal deaths due to pulmonary hypoplasia. In cases predicted to be non-lethal, nine resulted in live births, confirming the predictive accuracy of ultrasound markers. Conclusion: Ultrasound-based lethality markers effectively predicted perinatal outcomes in fetal skeletal dysplasia. However, challenges remain in cases with atypical presentations. Early diagnosis and standardized protocols for prenatal assessment are crucial for guiding parental counseling and management decisions.