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


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 4.79 ± 0.40%. 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 < 0.01). For example, in fully adjusted models, odds ratios (ORs) for birth weight >90th percentile for each measure higher by 1 SD were 1.39, 1.45, and 1.38, respectively, for fasting, 1-, and 2-h plasma glucose and 1.15 for A1C. ORs for cord C-peptide >90th percentile were 1.56, 1.45, and 1.35 for glucose, respectively, and 1.32 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.
Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA. lplowe@northwestern.edu
Lynn P
LP
Lowe
Boyd E
BE
Metzger
Alan R
AR
Dyer
Julia
J
Lowe
David R
DR
McCance
Terence R J
TR
Lappin
Elisabeth R
ER
Trimble
Donald R
DR
Coustan
David R
DR
Hadden
Moshe
M
Hod
Jeremy J N
JJ
Oats
Bengt
B
Persson
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D016640:Diabetes, Gestational / Q000097:blood; D005260:Female; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D006943:Hyperglycemia / Q000150:complications / Q000503:physiopathology*; D011247:Pregnancy; D011256:Pregnancy Outcome
D001786:Blood Glucose; D006442:Glycated Hemoglobin