## Objectives

To study the correlations between facial profile markers and crown-lump length (CRL) in a Chinese population, and to evaluate the clinical value of these markers for abnormal fetuses during the first trimester (11 to 13+ 6 gestational weeks) .

## Methods

The facial profile markers were as followings: inferior facial angle (IFA), maxilla-nasion-mandible (MNM) angle, facial maxillary angle (FMA), frontal space (FS) distance and profile line (PL) distance. These markers were measured in facial mid-sagittal section through ViewPoint 6 software. The diagnostic value of these markers for abnormal fetuses was assessed by receiver operating characteristic (ROC) curves.

## Results

According to the ultrasonic examination and follow-up, 31 fetuses were enrolled in the abnormal group, including 14 cases of trisomy 21, 7 cases of trisomy 18, 10 cases with cleft lip and palate (CLP), and 1000 cases were selected to the normal group, during the first trimester,with the CRL from 45mm to 84 mm. In the normal group, the IFA, FS distance and PL distance had negative correlations with CRL during the first trimester (rs=-0.614, *p* < 0.001; rs=-0.42, *p* < 0.001; rs=-0.271, *p* < 0.001). The MNM angle and FMA had positive correlations with CRL (rs=0574, *p* < 0.001; rs=0.451, *p* < 0.001). The mean IFA values for fetuses with trisomy 21 and trisomy 18 were 74.11° (standard deviation (SD) 7.48) and 69.88° (SD 7.08), respectively, which were significantly smaller than the normal group (Z=-2.496, *p* = 0.013; Z=-3.018, *p* = 0.003). The mean MNM angle of fetuses with trisomy 18 and CLP were 6.98° (SD 2.61) and 9.41° (SD 2.57), respectively, which were significantly greater than the normal group (Z=-2.83, *p* = 0.005; Z=-5.05, *p* < 0.001). The mean FMA values of trisomy 18 fetuses were 63.95° (SD 4.77), which was significantly smaller than the normal group (t = 4.777, *p* < 0.001). The mean FS distance of CLP fetuses was − 0.22mm (SD 1.38), which was significantly smaller than the normal group (Z=-4.259, *p* < 0.001). The mean PL distance of trisomy 21, trisomy 18 and CLP fetuses were 2.89mm (SD 0.41), 2.91mm (SD 0.56) and 2.71mm (SD 0.37), respectively. The difference with the normal group had no statistical significance (t=-0.583, *p* = 0.56; t=-0.515, *p* = 0.607; t = 0.613, *p* = 0.54).

## Conclusions

Fetal facial profile markers had excellent correlations with CRL during the first trimester. IFA had certain clinical significance in detecting trisomy 21. FMA, IFA and MNM angle were reliable indicators for screening trisomy 18. The abnormal MNM angle and FS distance could be used as sensitive indicators for CLP. However, PL distance was not the best markers for trisomy 21, trisomy 18 and CLP during the first trimester.