孕妇27岁,孕1产0,孕25周。无不良病史及家族病史,因羊水过多超声复查。产前超声检查:胎儿面部正中矢状切面,显示胎儿下颌小,下颌及下唇明显后缩,正常下唇下颌形成的“S”形曲线消失,上、下颌不能闭合,处于半张口状态(图1);羊水无回声区最大深度9.3cm,羊水指数为28.6cm;三维超声显示小下颌及张口(图2)。超声诊断:晚孕(单活胎);胎儿颜面部畸形,考虑小下颌畸形;羊水 27-year-old pregnant women, pregnant and pregnant 1 0, 25 weeks pregnant. No bad medical history and family history, due to excessive ultrasound review of amniotic fluid. Prenatal ultrasound examination: Fetal median sagittal section, showing the fetal mandibular small, mandibular and lower lip was significantly reduced, the normal lower lip formed by the “S” -shaped curve disappears, the upper and lower jaw can not be closed, in a half mouth state (Figure 1); amniotic fluid echo-free zone maximum depth of 9.3cm, amniotic fluid index was 28.6cm; three-dimensional ultrasound showed a small jaw and mouth (Figure 2). Ultrasound diagnosis: late pregnancy (single live fetus); fetus facial deformity, consider the small jaw deformity; amniotic fluid