Outcomes of singleton and twin pregnancies complicated by pre-existing diabetes and gestational diabetes: A population-based study in Alberta, Canada, 2005-11.

BACKGROUND

We assessed the prevalence and pregnancy outcomes of pre-existing diabetes mellitus (pre-DM) and gestational diabetes mellitus (GDM) in Alberta, Canada, 2005-11.

METHODS

327 198 singleton and 5552 twin pregnancies resulting in live births or stillbirths were included. The odds ratios of adverse outcomes were evaluated comparing pre-DM with no diabetes and GDM with no diabetes, controlling for maternal characteristics.

RESULTS

Diabetes complicated 6.3% of pregnancies, with 88% being GDM. In singleton pregnancies, pre-DM and GDM were associated with increased risks of pre-eclampsia (adjusted odds ratio [aOR] = 3.38 and 1.83, respectively), cesarean delivery (aOR 2.53, 1.55), spontaneous preterm (aOR 4.20, 1.71), and labor-induced preterm (aOR 3.82, 2.00) in the mother, and macrosomia (aOR 2.11, 1.30), shoulder dystocia (aOR 1.54, 1.32), congenital anomalies (aOR 1.61, 1.20), and neonatal intensive care unit (NICU) admissions (aOR 3.81, 1.60) in the infants. In addition, pre-DM was associated with an increased likelihood of stillbirth (aOR 3.73) and neonatal death (aOR 2.00) compared with non-diabetic pregnancies. In twin pregnancies, pre-DM was associated with increased risks of spontaneous (aOR 3.54) and labor-induced (aOR 3.57) preterm births, large for gestational age (LGA) infants (aOR 3.73), congenital anomalies (aOR 3.05) and NICU admissions (aOR 2.91); GDM was associated with an increased risk of pre-eclampsia (aOR 1.54), cesarean delivery (aOR 1.57), and LGA infants (aOR 1.63).

CONCLUSIONS

Pre-existing diabetes confers higher risks than GDM. Diabetes is associated with adverse outcomes in singleton and twin pregnancies, and the increased risks are generally similar or less in twins, probably due to their higher "baseline" risks and closer clinical monitoring.