Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study: associations of maternal A1C and glucose with pregnancy outcomes.

TLDR: It is suggested that A1C measurement is not a useful alternative to an OGTT in pregnant women on the basis of associations with adverse outcomes.

Abstract: OBJECTIVE To compare associations of maternal glucose and A1C with adverse outcomes in the multinational Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study and determine, based on those comparisons, if A1C measurement can provide an alternative to an oral glucose tolerance test (OGTT) in pregnant women RESEARCH DESIGN AND METHODS Eligible pregnant women underwent a 75-g OGTT at 24–32 weeks’ gestation A sample for A1C was also collected Neonatal anthropometrics and cord serum C-peptide were measured Associations with outcomes were assessed using multiple logistic regression with adjustment for potential confounders RESULTS Among 23,316 HAPO Study participants with glucose levels blinded to caregivers, 21,064 had a nonvariant A1C result The mean ± SD A1C was 479 ± 040% Associations were significantly stronger with glucose measures than with A1C for birth weight, sum of skinfolds, and percent body fat >90th percentile and for fasting and 1-h glucose for cord C-peptide (all P 90th percentile for each measure higher by 1 SD were 139, 145, and 138, respectively, for fasting, 1-, and 2-h plasma glucose and 115 for A1C ORs for cord C-peptide >90th percentile were 156, 145, and 135 for glucose, respectively, and 132 for A1C ORs were similar for glucose and A1C for primary cesarean section, preeclampsia, and preterm delivery CONCLUSIONS On the basis of associations with adverse outcomes, these findings suggest that A1C measurement is not a useful alternative to an OGTT in pregnant women