Reference range for glycated haemoglobin in full term non diabetic pregnant women: a multicentric cross sectional study.

BACKGROUND

There are no large studies to define the normal value of glycated haemoglobin (HbA1c) measured in full term pregnant women measured at the time of delivery.

RESEARCH DESIGN AND METHODS

The study was conducted at three government hospitals in South India. Clinical data, maternal blood sample and foetal cord blood sample were collected from women admitted for safe confinement. Mean (± SD) of HbA1c in participants with no known diabetes (gestational or pregestational) or any complications (maternal or fetal) is described, 2.5th-97.5th centile reference range was derived.

RESULTS

From 3 centres, 2004 women participated in the study. Data from 1039 participants who had no history of diabetes or any maternal or fetal complication were used to determine the reference range for HbA1c at term pregnancy. The mean HbA1c in subjects devoid of diabetes and its known complications was 5.0 (± 0.39) %. The reference range for normal HbA1c at term in these women was found to be 4.3-5.9%. Maternal HbA1c at term pregnancy in non-diabetic pregnant women is associated with pre-pregnancy BMI, maternal age and 2-h plasma glucose level of 2nd trimester oral glucose tolerance test (OGTT).

CONCLUSIONS

The mean HbA1c at term pregnancy in non-diabetic women admitted for safe confinement is 5.00 (± 0.39) %. An HbA1c of 5.9% or more at term should be considered abnormal and women with such a value may be kept at a close surveillance for development of diabetes.