Maternal serum alpha fetoprotein and free β-hCG of second trimester for screening of fetal gastroschisis and omphalocele

Abstract

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. 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. 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. MSAFP of second trimester is a better biomarker than free β-hCG in screening abdominal wall defects.