Prenatal diagnosis of hemoglobinopathies by chorionic villus sampling: A large single-center experience.

Abstract

Objective: Hemoglobinopathies are among the most common inherited disorders worldwide. Given the high prevalence and carrier rates in our region, this study aimed to evaluate the obstetric, genetic, and procedure-related outcomes of pregnancies undergoing chorionic villus sampling (CVS) for prenatal diagnosis.

Materials and methods: This retrospective observational study included 1,330 pregnant women referred for hemoglobinopathy screening between January 2008 and December 2012. Data regarding gestational age, indication for CVS, placental location, number of insertions, complications, and genetic results were analyzed. Transabdominal CVS was primarily performed between 10 and 14 weeks of gestation.

Results: The mean gestational age at CVS was 12.4±1.03 weeks. Late referral (≥14 weeks) was observed in 8.8% of cases. Adequate sampling was achieved with a single insertion in 88.3% of procedures. The overall complication rate was 2.6%, with a fetal loss rate of 1.8% and an incidence of chorioamnionitis of 0.07%. Multiple insertions (p=0.036) and posterior placental location (odds ratio: 2.21; 95% confidence interval: 1.11-4.38; p=0.033) were significantly associated with an increased risk of complications. Genotype analysis showed that 50.2% of fetuses were carriers, 25.4% were normal, and 21% were affected. Pregnancy termination was performed in most of the affected cases (n=266), while 11 cases resulted in live births. Hemoglobin S (HbS) was the most frequent variant (31%), followed by HbD and HbE. The most common β-thalassemia mutation was IVS-I-110 (G>A), and the most frequent α-thalassemia mutation was -α^3.7 deletion.

Conclusion: CVS is a reliable and effective method for early prenatal diagnosis of hemoglobinopathies. Procedure-related risks are influenced by technical factors, such as the number of insertions and placental location. Standardization of techniques and operator experience may reduce complications. In high-prevalence regions, the integration of carrier screening and early prenatal diagnosis is essential to reduce the disease burden.