ABSTRACT
Objective: The purposes of this study were to review the prevalence of skeletal dysplasias among fetal anomaly cases and to demonstrate common findings detected prenatally by ultrasonography. Methods: Twenty prenatal cases diagnosed of skeletal anomalies between January 2000 and December 2005 at Anomaly Clinic, Maternal-Fetal Medicine Unit, Siriraj Hospital were reviewed retrospectively. Demographic data such as maternal age, gravida, parity, gestational age at first diagnosis were collected, including prenatal ultrasound findings. Final diagnosis and pregnancy outcome after termination of pregnancy were also demonstrated. Results: The prevalence of skeletal dysplasias among fetal anomaly cases in the study interval was 3.86% (20/518 cases and 95%CI=2.51%, 5.89%). Mean maternal age was 30.3(+ 5.3) years old. The most likely time of diagnosis was 26 (+ 5.7) weeks of gestation. The most common type diagnosed prenatally was thanatophoric dysplasia (40%). All cases of prenatal ultrasound findings of suspected skeletal dysplasias demonstrated short limbs. Three cases were non-lethal anomalies and the parents decided to continue pregnancy. In the remaining 17 cases, the parents were counseled about lethal prognosis of their fetuses and only 11 cases decided to terminate pregnancy at our hospital. Thanatophoric dysplasia was the most common diagnosis after termination of pregnancy (9 in 11 cases). Conclusion: Fetal skeletal dysplasias are one of fetal anomalies which can be detected prenatally by routine ultrasonography. Detection of abnormal long bone length is the important finding. Thorough scanning of all bony characteristics can help clinicians about prenatal diagnosis and pregnancy outcomes.