Fetal akinesia deformation sequence in previable fetuses.

We reviewed the morphologic findings of 948 previable fetuses and identified the fetal akinesia deformation sequence (FADS) in 16 cases. In eight fetuses who had joint contractures, micrognathia, and pulmonary hypoplasia, the cause of fetal akinesia could be attributed to an abnormal intrauterine environment restricting fetal movement. The other eight fetuses had pterygia across the immobilized joints, in addition to main manifestations of FADS. Since most of the fetuses with pterygia were of only 8-9 weeks developmental age, we suggest that embryonic onset of immobility interferes with limb development and results in joint fixation and pterygium formation, in contrast to fetal-onset immobility, which causes joint contractures alone.