LACK OF MANDIBULAR MOVEMENT MANIFESTED BY ABSENT FETAL SWALLOWING - APOSSIBLE FACTOR IN THE PATHOGENESIS OF MICROGNATHIA

This study was performed to assess the association of lack of mandibul ar movement as manifested by absent fetal swallowing and micrognathia in a nonrestrictive intrauterine environment. Over a 5-year period, 14 fetuses with sonographic findings of polyhydramnios (amniotic fluid i ndex [AFI] more than 20 cm), absent mandibular movement, and a nonvisu alized fetal stomach, all consistent with absent fetal swallowing, wer e followed. A group of 14 fetuses, each with polyhydramnios (AFI more than 20 cm) yet with sonographic detection of fetal swallowing, served as controls. All gravidas in both groups were normoglycemic throughou t gestation. Subsequent mandibular development was assessed at deliver y or autopsy. Analysis of the data revealed th at in the study group, 12 of these infants were liveborn, and two were stillborn. Eleven of t he liveborn infants had an early neonatal death. All 14 infants of the study group demonstrated micrognathia. None of the control infants (a ll of whom survived) had micrognathia. In conclusion, this study suppo rts the concept that normal mandibular growth may depend on the presen ce of mandibular movement during intrauterine development.