HAPO Study Cooperative Research Group, Metzger, B. E., Lowe, L. P., Dyer, A. R., Trimble, E. R., Chaovarindr, U., Coustan, D. R., Hadden, D. R., McCance, D. R., Hod, M., McIntyre, H. D., Oats, J. J., Persson, B., Rogers, M. S., & Sacks, D. A. (2008).New England Journal of Medicine, 358(19), 1991-2002.
The problem of maternal hyperglycemia that does not reach the threshold of gestational diabetes was the subject of the HAPO (Hyperglycemia and Adverse Pregnancy outcomes) study, which was conducted in 15 prenatal care centers in nine countries from 2000 to 2006. A total of 25,505 women participated, undergoing 75-gram glucose tolerance testings (GTT) at 24 to 32 weeks gestation. Women with fasting glucose results of 105 mg/dL or less and those with results of 200 mg/dL or less on the 2 hour test (n = 23,316) were included in the final study group. The aim of the research was to clarify the risk of adverse outcomes associated with various degrees of maternal glucose intolerance, which have been considered less severe than those in overt diabetes mellitus.
These researchers examined four primary variables: (1) birth weight >90th percentile for gestational age, (2) primary cesarean birth, (3) clinical neonatal hypoglycemia, and (4) cord blood serum peptide >90th percentile. This study found a strong linear continuous association of maternal glucose level with increased birth weight and increased cord blood serum C peptide. Weaker association was found between cesarean birth and neonatal hypoglycemia. Secondary outcomes of preeclampsia, shoulder dystocia or birth injury; premature delivery, hyperbilirubinemia, and NICU admission also showed a weak association. What can we learn from the HAPO study? Although the study did not establish a threshold for the need of treatment for hyperglycemia, women who are found to have hyperglycemia during pregnancy should be helped to keep their blood sugar levels within normal limits to minimize negative effect of hyperglycemia on the fetus.