Second-trimester maternal serum alpha-fetoprotein, unconjugated estriol, and hCG levels in pregnancies with ventral wall defects.

OBJECTIVE: To determine if second-trimester maternal serum concentrations of unconjugated estriol (E3) and hCG are altered in pregnancies associated with fetal gastroschisis or omphalocele. METHODS: Concentrations of alpha-fetoprotein (AFP), unconjugated E3, and hCG were measured in a case-control study involving 23 cases of gastroschisis, 17 cases of omphalocele, and 200 matched unaffected pregnancies. RESULTS: As reported previously, median AFP levels were significantly higher in pregnancies with gastroschisis and omphalocele compared to unaffected pregnancies (9.42 and 4.18 multiples of the unaffected population median [MoM], respectively). The median hCG values were not significantly different for the two defects (1.10 and 1.13 MoM, respectively). Six of the cases of omphalocele were associated with other anomalies, but exclusion of these cases from the analysis did not alter the conclusions. CONCLUSIONS: Unconjugated E3 and hCG measurements are not useful in screening for, or distinguishing between, open ventral wall defects. Alpha-fetoprotein measurements alone will detect nearly all cases of gastroschisis and most cases of omphalocele.