Glycemic targets in the second and third trimester of pregnancy for women with type 1 diabetes

• Published in: Diabetes care Vol. 38; no. 1; pp. 34 - 42
• Main Authors: Maresh, Michael J A, Holmes, Valerie A, Patterson, Christopher C, Young, Ian S, Pearson, Donald W M, Walker, James D, McCance, David R
• Format: Journal Article
• Language: English
• Published: United States American Diabetes Association 01.01.2015
• Subjects: Adult; Birth Weight; Blood Glucose - analysis; Body Mass Index; Childbirth & labor; Clinical outcomes; Diabetes; Diabetes Mellitus, Type 1 - blood; Diabetes Mellitus, Type 1 - complications; Female; Glucose; Glycated Hemoglobin A - metabolism; Health risk assessment; Humans; Infant, Newborn; Logistic Models; Maternal & child health; Postprandial Period - physiology; Pre-Eclampsia - blood; Pregnancy; Pregnancy Complications; Pregnancy Outcome; Pregnancy Trimester, Second - blood; Pregnancy Trimester, Third - blood; Premature Birth - etiology; Prospective Studies; Randomized Controlled Trials as Topic; Young Adult
• ISSN: 0149-5992; 1935-5548
• DOI: 10.2337/dc14-1755

To assess the relationship between second and third trimester glycemic control and adverse outcomes in pregnant women with type 1 diabetes, as uncertainty exists about optimum glycemic targets. Pregnancy outcomes were assessed prospectively in 725 women with type 1 diabetes from the Diabetes and Pre-eclampsia Intervention Trial. HbA1c (A1C) values at 26 and 34 weeks' gestation were categorized into five groups, the lowest, <6.0% (42 mmol/mol), being the reference. Average pre- and postprandial results from an eight-point capillary glucose profile the previous day were categorized into five groups, the lowest (preprandial <5.0 mmol/L and postprandial <6.0 mmol/L) being the reference. An A1C of 6.0-6.4% (42-47 mmol/mol) at 26 weeks' gestation was associated with a significantly increased risk of large for gestational age (LGA) (odds ratio 1.7 [95% CI 1.0-3.0]) and an A1C of 6.5-6.9% (48-52 mmol/mol) with a significantly increased risk of preterm delivery (odds ratio 2.5 [95% CI 1.3-4.8]), pre-eclampsia (4.3 [1.7-10.8]), need for a neonatal glucose infusion (2.9 [1.5-5.6]), and a composite adverse outcome (3.2 [1.3-8.0]). These risks increased progressively with increasing A1C. Results were similar at 34 weeks' gestation. Glucose data showed less consistent trends, although the risk of a composite adverse outcome increased with preprandial glucose levels between 6.0 and 6.9 mmol/L at 34 weeks (3.3 [1.3-8.0]). LGA increased significantly with an A1C ≥6.0 (42 mmol/mol) at 26 and 34 weeks' gestation and with other adverse outcomes with an A1C ≥6.5% (48 mmol/mol). The data suggest that there is clinical utility in regular measurement of A1C during pregnancy.