Amniotic fluid glucose concentration as a predictor of fetal trisomy

Aim: We aimed to assess the amniotic fluid glucose concentration cut-off as an indicator of fetal chromosomal abnormalities, such as trisomy 13, 18, and 21.

Methods: This prospective observational study included pregnant females who underwent amniocentesis. Participants were divided into two groups on the border of 22 weeks of gestational age (<22 and ≥22-week groups).

Results: In total, 224 pregnant females were included in the analysis. In the <22 week group, 15 females had trisomies 13/18/21 and 174 females had no trisomies. In the ≥22 week group, 18 females had trisomies 13/18/21 and 17 had no trisomies. In each group, there was a difference in amniotic fluid glucose concentration between fetuses with trisomies 13, 18, and 21 and other fetuses with normal karyotype or minor chromosomal abnormalities. In both groups, the amniotic glucose concentration was noticeably lower in trisomies 13/18/21 (p = 0.002 in the <22 week group; p = 0.039 in the ≥22 week group). According to receiver operating characteristic curves, the optimal cut-off point of glucose concentration was 46 mg/dL in the <22 week group (odds ratio 6.55; 95% confidence interval 1.78-24.1) and 24 mg/dL in the ≥22 week group (odds ratio 8.40; 95% confidence interval 1.83-38.6).

Conclusions: Our study suggested that glucose concentration in amniotic fluid is an indicator of trisomy 13, 18, and 21. Amniotic fluid glucose concentration itself does not diagnose fetal trisomy, but this may be helpful in selecting treatment facilities.