Impaired maternal glucose tolerance can lead to poor pregnancy outcomes, and clinicians should use a lower threshold to diagnose and treat gestational diabetes, according to M. Kwik of the University of Sydney in Australia.
“Untreated glucose intolerance in pregnancy is associated with larger babies, more shoulder dystocia, and higher rates of preeclampsia,” reported M. Kwik and colleagues in Diabetes Research and Clinical Practice (2007 [Epub doi: 10.1016/j.daibres.2006.12.004]).
The researchers conducted a retrospective study of women with a singleton pregnancy who received prenatal care at their hospital between February 2000 and May 2005. They excluded women who gave birth before 34 weeks' gestation. The researchers identified 512 women with a 2-hour glucose level of at least 7.8 mmol/L and a fasting glucose at or below 5.5 mmol/L following a 75-g glucose tolerance test (GTT). They obtained information on pregnancy outcomes for 478 (93%) of these women. The treated group comprised 265 women who had 2-hour glucose levels of more than 7.8 mmol/L and were diagnosed with gestational diabetes mellitus (GDM); these patients were managed according to guidelines. Another 213 women had 2-hour glucose levels of more than 7.8 mmol/L, but did not meet criteria for GDM. They constituted the untreated group. The researchers also evaluated 197 women with GTT values of 7.8 mmol/L or less who did not receive GDM management, and these participants were the comparison group. There were no significant differences in maternal age, body mass index, or proportion of primiparous women in the three groups.
The results showed a significant increase in mean birth weight, macrosomia, and shoulder dystocia in the untreated group, vs. the comparison group (5.2% vs. 1.0%). There was also a statistically significant increase in induction of labor rates in the untreated group, vs. the comparison group (27.7 % vs. 19.3 %). Additionally, the results showed a significantly higher preeclampsia rate in the untreated group vs. the comparison group (11.7% vs. 5.1%). The two groups' cesarean rates were similar.