The association between low 50 g glucose challenge test values and adverse pregnancy outcomes

Abstract

Objective: To compare the pregnancy outcomes in pregnant women with low 50 g glucose challenge test (GCT) values to those of pregnant women with normal values. Methods: This retrospective study was conducted in pregnant women undergoing gestational diabetes mellitus (GDM) screening tests at 24-28 weeks gestational age between January 2010 and December 2016. Women with multifetal pregnancies, type I or II diabetes before pregnancy, GCT performed prior to 24 or after 28 weeks of gestational age, and women undergoing multiple GCTs in the same pregnancy were excluded. Pregnancy outcomes in women with low GCT values [<tenth percentile (≤85 mg/dL)] were compared with those of women with normal GCT values (86-130 mg/dL). Results: Of 3875 screened subjects, 519 (13.4%) women were included in the low GCT group and 3356 (86.6%) were included in the normal GCT group. Women in the low GCT group had a significantly higher rate of small for gestational age (SGA) infants than did women in the normal GCT group (10.8% vs. 7.9%, p=0.02). Cesarean section and postpartum hemorrhage (PPH) were less frequent in the low GCT group than in the normal group (32.6% vs. 42.8%, p<0.01 and 0.2% vs. 1.2%, p=0.03, respectively). Women with low GCT values had a 1.38-fold increased independent risk of bearing SGA infants (95% CI: 1.01-1.88, p=0.04). Conclusion: Women with low 50 g GCT values had significantly higher rates of SGA infants and significantly lower rates of cesarean delivery and PPH. Low GCT values were independently associated with increased risk of SGA.