First trimester maternal serum alpha-fetoprotein in fetal trisomies.

OBJECTIVE

To evaluate the potential value of maternal serum alpha-fetoprotein concentration in the detection of fetal trisomy at 10 to 13 weeks gestation and to examine the possible association between maternal serum alpha-fetoprotein and fetal nuchal translucency thickness.

DESIGN

Cross-sectional study.

SETTING

Harris Birthright Research Centre for Fetal Medicine, King's College Hospital Medical School, London.

SUBJECTS AND METHODS

Maternal serum alpha-fetoprotein concentration was measured at 10 to 13 weeks gestation in samples from 57 pregnancies with fetal trisomies (trisomy 21 (n = 35), trisomy 18 (n = 16), and trisomy 13 (n = 6)) in 228 matched controls in whom the fetal nuchal translucency was < 3 mm and in 114 chromosomally normal fetuses with translucency > or = 3 mm.

RESULTS

In the control group maternal serum alpha-fetoprotein increased significantly with fetal crown-rump length (r = 0.451). In this group, the median maternal serum alpha-fetoprotein was not significantly different from that in the groups with trisomy 21 (median = 0.84 MoM), trisomy 18 (median = 0.86 MoM), or trisomy 13 (median = 0.94 MoM), respectively. Neither in the control group nor in the group with trisomic fetuses was maternal serum alpha-fetoprotein significantly associated with fetal nuchal translucency thickness (r = 0.01 and r = 0.03).

CONCLUSION

Measurement of maternal serum alpha-fetoprotein concentration in the first trimester of pregnancy is not likely to be useful in the prediction of fetal trisomies.