Consequences of smoking and caffeine consumption during pregnancy in women with type 1 diabetes

To test the hypothesis that, in women with type 1 diabetes, prenatal smoking and caffeine consumption during pregnancy are associated with an increased risk of adverse maternal and perinatal outcomes.

A secondary analysis of data on pregnant women with type 1 diabetes from an interdisciplinary program of Diabetes in Pregnancy. Women were interviewed monthly, by a trained non-medical member of the research team, using a standardized questionnaire, to ascertain daily smoking habits and caffeine consumption.

Smoking and caffeine information were available on 191 pregnancies, 168 progressing beyond 20 weeks of gestation. Early pregnancy smoking (OR 3.3, 95% CI 1.2, 8.7) and caffeine consumption (OR 4.5, 95% CI 1.2, 16.8) were associated with increased risk of spontaneous abortion when controlling for age, years since diagnosis of diabetes, previous spontaneous abortion, nephropathy and retinopathy. Smoking throughout pregnancy was significantly associated with decreased birth weight and prolonged neonatal hospital stay. Smoking throughout pregnancy (OR 0.2, 95% 0.1, 1.0) and caffeine consumption after 20 weeks (OR 0.3, 95% CI 0.1, 1.0) were associated with reduced risk of pre-eclampsia.

Caffeine consumption during early pregnancy, regardless of glycemic control, increases the risk of spontaneous abortion. Smoking throughout pregnancy and caffeine consumption are associated with reduced risk of pre-eclampsia.