OP31.04: Incidence and outcome of antenatally diagnosed skeletal dysplasia

Abstract

To investigate the incidence and outcome of antenatally diagnosed skeletal dysplasia We investigated all cases of fetal skeletal dysplasia referred to a tertiary Fetal Medicine unit between 2002 and 2008. The ultrasound findings, concordance between antenatal and final diagnosis as well as pregnancy outcome were analyzed. Data were collected from the Fetal Medicine database and computerized records supplemented by individual chart reviews. Thirty three cases of skeletal dysplasia were identified. The median maternal age was 30 years (range 18–40) and the median gestational age at referral was 21 weeks (range 11–35 weeks). A provisional ultrasound diagnosis was possible in 21/33 (65%) cases. This diagnosis was however confirmed postnatally or after molecular testing in only half of the cases. The commonest skeletal dysplasia were thanatophoric dysplasia (n = 7) and osteogenesis imperfecta (n = 4). The perinatal outcome in this series was very poor with 64% pregnancies terminated (21/33), 9% (3/33) stillborn, 9% (3/33) died in early neonatal period and only 18% (6/33) alive after the neonatal period. Making a precise prenatal diagnosis of skeletal dysplasia is frequently difficult and often inaccurate. Prediction of lethality is however much easier and is often possible depending on thoracic circumference, degree of limb shortening or the presence of other abnormalities. Parents need to be aware that the outcome of many skeletal dysplasias is poor. Although a precise diagnosis is frequently not possible antenatally, the ultrasound findings usually allow an assessment of perinatal outcome. Decisions about termination of pregnancy can therefore be made with some confidence.