中孕期母血清甲胎蛋白和游离β-hCG筛查胎儿腹裂和脐膨出的效率

目的：评估中孕期母血清甲胎蛋白（MSAFP）和游离人绒毛膜促性腺激素β亚基（β-hCG）在产前筛查胎儿腹裂和脐膨出中的价值。方法：回顾性分析2007年10月至2016年9月在杭州市五家产前筛查中心自愿接受产前筛查的622 639名孕妇的出生缺陷监测资料及产前筛查随访结果。根据有无胎儿先天性腹壁缺损（腹裂、脐膨出）将研究对象分为病例组和健康对照组。病例组是指经超声诊断并通过终止妊娠确诊为腹裂和脐膨出胎儿的孕妇共60例，包括腹裂组30例、脐膨出组30例；健康对照组为随机抽取同时期胎儿发育正常的孕妇116名。采用时间分辨荧光免疫法检测两病例和健康对照组MSAFP、游离β-hCG水平。用受试者工作特征（ROC）曲线对MSAFP和游离β-hCG的筛查效能进行评价。结果：腹裂组孕妇MSAFP水平为4.41（0.88~11.69）MOM，脐膨出组为2.31（0.72~23.20）MOM，均高于健康对照组的0.98（0.41~2.26）MOM，差异均有统计学意义（均P<0.01）。腹裂组血清游离β-hCG水平为1.25（0.35~19.94）MOM，高于健康对照组的0.86（0.17~6.11）MOM，差异有统计学意义（P<0.05）；脐膨出组游离β-hCG水平为1.03（0.21~8.95）MOM，与健康对照组比较差异无统计学意义（P>0.05）。MSAFP筛查腹裂和脐膨出胎儿的AUC分别为0.897（95%CI：0.822~0.972）和0.852（95%CI：0.762~0.942）（均P<0.01）。MSAFP筛查先天腹壁缺损（腹裂、脐膨出）的最佳临界值为1.655 MOM，此时的敏感度为68.30%，特异度为99.60%，约登指数为0.649。结论：中孕期MSAFP筛查先天腹壁缺损具有较高的敏感度和特异度，是筛查先天腹壁缺损的一个较好的标志物。
Abstract: Objective:To assess the detection of maternal serum alpha fetoprotein (MSAFP) and free beta-HCG levels of second trimester for screening of fetal gastroschisis and omphalocele. Methods:Clinical data of 622 639 pregnant women from 5 prenatal screening centers in Hangzhou during October 2007 and September 2016 were analyzed retrospectively. Thirty cases of gastroschisis and 30 cases of omphalocele diagnosed by ultrasonography and postmortem findings were enrolled in the study and 116 cases of pregnant women with normal fetal development during the same period were selected as control group. The cut-off value and area under ROC curve (AUC) of MSAFP and free β-hCG for diagnosis of fetal gastroschisis and omphalocel were analyzed. Results:MSAFP levels of women with fetal gastroschisis and omphalocele were 4.41 (0.88-11.69) MOM and 2.31 (0.72-23.20) MOM, which were significantly higher than that of control group[0.98 (0.41-2.26) MOM, all P<0.01]. Free β-hCG level of women with fetal gastroschisis was 1.25 (0.35-19.94) MOM, which was significantly higher than that of control group[0.86 (0.17-6.11) MOM, P<0.05). But there were no significant difference in free β-hCG between fetal omphalocele group[1.03(0.21-8.95)]and control group (P>0.05). The AUCs of MSAFP for diagnosis of gastroschisis and omphalocele were 0.897 (95% CI:0.822-0.972) and 0.852(95% CI:0.762-0.942), respectively (all P<0.01). Taking 1.655 MOM as the cut-off value of MSAFP for abdominal wall defects (gastroschisis and omphalocele), the sensitivity was 68.30%, specificity was 99.60% and Youden index was 0.649. Conclusion:MSAFP of second trimester is a better biomarker than free β-hCG in screening abdominal wall defects. Key words: Chorionicgonadotropin, beta subunit, human/blood