Purpose
The aim of our study was to investigate to what degree clinical characteristics can contribute to incidence and structure of pregnancy and childbirth complications in women with diabetes, and to reveal key risk factors for adverse outcomes.

Methods
We conducted a retrospective single-center cohort study from January 2008 through December 2017, including 3069 singleton pregnancies, affected by type 1 diabetes (T1D, n = 498), type 2 diabetes (T2D, n = 214), and gestational diabetes mellitus (GDM, n = 2357).

Results
More than 10 years duration of T1D associated with increased risk for preterm birth (RR 2.03, 95% CI 1.28–3.20) and preeclampsia (RR 1.57, 95% CI 1.09–2.26). Diabetic nephropathy, same as diabetic proliferative retinopathy, was associated with increased risk of C-section, preeclampsia development, SGA delivery. In patients with T1D who received CSII (12%), we do not report superior outcomes compared to MDI. Pre-pregnancy HbA1c level less than 6.5% reduced the risk of preeclampsia for T1D (RR 0.28, 95% CI 0.19–0.67) and risk of LGA birth for T2D (RR 0.43, 95% CI 0.19–0.92). Achieving glycemic target values by full-term pregnancy reduced the risk of excessive fetal adiposity (RR 0.81 for T1D, RR 0.39 for T2D). For T2D and GDM, the leading risk factors were obesity and chronic hypertension. For patients with GDM, insulin administration and early diagnosis of GDM were the significant risk factors for adverse outcomes.

Conclusion
Diabetes during pregnancy is challenging for the clinician, but optimizing glycemic control, treatment regimens, and close attention to comorbidities can help to reduce the risks and ensure appropriate quality diabetes management.