This study assessed pregnancy outcomes in women with type 1 diabetes (T1D) over the last 15 years and identified modifiable factors associated with good perinatal outcomes.

Pregnancy outcomes were prospectively assessed in this cohort study of 588 singleton pregnancies (441 women) managed by standardized care from 2000 to 2014. A good perinatal outcome was defined as the uncomplicated delivery of a normally formed, non-macrosomic, full-term infant with no neonatal morbidity. Factors associated with good perinatal outcomes were identified by logistic regression.

The rate of severe congenital malformations was 1.5%, and 0.7% for perinatal mortality. The most frequent perinatal complications were macrosomia (41%), preterm delivery (16%) and neonatal hypoglycaemia (11%). Shoulder dystocia occurred in 2.6% of cases, but without sequelae. Perinatal outcomes were good in 254 (44%) pregnancies, and were associated with lower maternal HbA_1c values at delivery [adjusted odds ratio (aOR): 2.78, 95% CI: 2.04–3.70, for each 1% (11mmol/mol) absolute decrease], lower gestational weight gains (aOR: 1.06, 95% CI: 1.02–1.10) and absence of preeclampsia (aOR: 2.63, 95% CI: 1.09–6.25). The relationship between HbA_1c at delivery and a good perinatal outcome was continuous, with no discrimination threshold.

In our study, rates of severe congenital malformations and perinatal mortality were similar to those of the general population. Less severe complications, mainly macrosomia and late preterm delivery, persisted. Also, our study identified modifiable risk factors that could be targeted to further improve the prognosis of pregnancy in T1D.