Obstetric and Perinatal Outcomes in Type 1 Diabetic Pregnancies

OBJECTIVE To perform comparative analyses of obstetric and perinatal outcomes between type 1 diabetic pregnancies and the general obstetric population in Sweden between 1991 and 2003. RESEARCH DESIGN AND METHODS This was a population-based study. Data were obtained from the Medical Birth Registry, covering >98% of all pregnancies in Sweden. A total of 5,089 type 1 diabetic pregnancies and 1,260,207 control pregnancies were included. Odds ratios (ORs) were adjusted for group differences in maternal age, parity, BMI, chronic hypertensive disease, smoking habits, and ethnicity. RESULTS In type 1 diabetes, preeclampsia was significantly more frequent (OR 4.47 [3.77-5.31]) as was delivery by cesarean section (5.31 [4.97-5.69]) compared with results for the general population. Stillbirth (3.34 [2.46-4.55]), perinatal mortality (3.29 [2.50-4.33]), and major malformations (2.50 [2.13-2.94]) were more common in type 1 diabetic than in control pregnancies. The risk of very preterm birth (<32 gestational weeks) was also higher among type 1 diabetic women (3.08 [2.45-3.87]). The incidence of fetal macrosomia (birth weight >or=2 SD above the mean) was increased in the diabetic group (11.45 [10.61-12.36]). CONCLUSIONS Type 1 diabetes in pregnancy is still associated with considerably increased rates of adverse obstetric and perinatal outcomes. The eightfold increased risk for fetal macrosomia in type 1 diabetic pregnancies is unexpected and warrants further investigation.