应用二维及三维超声评估正常胎儿颜面的轮廓线，探索胎儿轮廓线随孕周的变化趋势，并分析染色体异常胎儿超声测量图中的轮廓线表现。

在胎儿颜面正中矢状切面上确定轮廓线，定义为鼻根与下颌骨正中前顶点的连线。首先分析2013年4月至2014年2月于北京协和医院进行产科超声检查的439例孕11~38周单胎妊娠正常胎儿的颜面轮廓线，根据此直线与胎儿额骨的关系分为3种类型：颜面轮廓线与额骨重合，颜面轮廓线位于额骨前方，颜面轮廓线与额骨相交，当轮廓线与额骨相交时测量轮廓线到额骨外缘的最大距离F值；其次，回顾性分析26例染色体异常胎儿颜面轮廓线测量结果，包括21例21-三体胎儿（孕13~33周）和5例18-三体胎儿（孕21~31周）。

439例正常胎儿中均未出现轮廓线位于额骨前方这一类型，405例表现为轮廓线与额骨重合，占92.26%，颜面轮廓线与额骨相交34例，占7.74%，集中在孕11~13周及孕26~38周胎儿，F值为0.10~0.51 cm，平均值（0.24±0.10）cm。21例21-三体胎儿中，颜面轮廓线与额骨重合14例，颜面轮廓线位于额骨前方3例，4例表现为颜面轮廓线与额骨相交，F值0.23~0.55 cm，平均值（0.39±0.14）cm。5例18-三体胎儿中，2例胎儿颜面轮廓线与额骨重合，3例表现为小下颌，颜面轮廓线位于额骨前方。

正常胎儿中未出现颜面轮廓线位于额骨前方。胎儿颜面轮廓线可于颜面正中矢状切面评估前额与下颌的相对位置，对颜面扁平、小下颌等颜面轮廓异常具有一定提示作用。

To evaluate the fetal profile (FP) line with two-dimensional and three dimensional ultrasound, to explore the changes of fetal facial profile with gestational age,and to analyze the manifestation of FP line for abnormal chromosomal fetuses.

FP line, which was defined as the line that passes through the anterior border of mandible and the nasion, was test on the facial mid-sagittal plane. Firstly, from April 2013 to January 2014, FP line was analyzed in 439 normal fetuses of Peking Union Medical College Hospital at 11-38 weeks of gestation. According to the relationship between FP line and fetal frontal bone,it was divided into three types: the FP line passed anteriorly, across or posteriorly to the frontal bone, respectively. When the FP line passed posteriorly to the frontal bone, the distance (F distance) between the FP line with the frontal bone was measured. Secondly, 26 pathological fetuses (21 trisomy 21 fetuses with 13-33 weeks′ gestation and 5 trisomy 18 fetuses with 21-31 weeks′ gestation) were analyzed respectively.

No cases with a FP line passed anteriorly to the frontal bone were found in all of normal fetuses. Most commonly seen was that FP line passed across to the frontal bone (92.26%). The FP line passed posteriorly to the frontal bone in up to 7.74%, and the mean F distance was 0.24 cm (range, 0.10-0.51 cm). In 21 fetuses of trisomy 21, 14 cases showed the FP line passed across to frontal bone, and 4 cases showed the FP line passed posteriorly frontal bone with the F distance from 0.23 cm to 0.55 cm. Three cases with sloping forehead with FP line passed anteriroly to frontal bone. As to 5 cases of trisomy 18, 2 cases showed FP line passed across to frontal bone, and 3 cases with micrognathia had FP line passed anteriroly to frontal bone.

No cases with a FP line passed anteriorly to the frontal bone were found in normal fetuses. The FP line, as a reference line for forehead and mandible abnormality, may be a useful tool to detect second trimester profile abnormalities such as sloping forehead and retrognathia.