Back ground:

Women with pre-existing diabetes represent a high risk group during pregnancy.  The aim of the study is to compare clinical characteristics of women with pre-existing type 1 and type 2 diabetes mellitus during pregnancy in one institution.  

Methods:

All singleton pregnancies complicated by pre-existing diabetes that were managed at the high-risk antenatal clinic at Liverpool Hospital between July 2007 and December 2011 were included in this study. 

Results:

There were 161 singleton pregnancies complicated by pre-existing diabetes during this period. Forty-four pregnancies were complicated by type 1 diabetes (27.3%) while 117 pregnancies were complicated by type 2 diabetes.  Women with type 2 diabetes were older and heavier than those with type 1 diabetes. At the end of pregnancy, their median daily insulin dose was also higher (122units versus 78units, p<0.001).  On the other hand, women with type 1 diabetes had longer duration of diabetes, and higher rates of smoking than women with type 2 diabetes. The first trimester HbA1c, rate of retinopathy and albuminuria were not different between the 2 groups.

As for pregnancy outcomes, 24.4% of women with type 1 diabetes gave birth prior to 36 weeks’ gestation, compared with 10.5% for women with type 2 diabetes (p=0.03).  Furthermore, 54.8% of women with type 1 diabetes gave birth to neonates with birth-weight above 90^th percentile, compared to 33.6% for women with type 2 diabetes (p=0.02).   There was no difference in the rate of pre-eclampsia, need for emergency Caesarian, fetal/neonatal death, congenital abnormalities and neonatal intensive care unit admission (NICU) between off-springs of women with type 1 and type 2 diabetes.  

Conclusions:

This study showed that the clinical characteristics of pregnant women with type 1 and type 2 diabetes varied greatly, but most pregnancy outcomes such as fetal/neonatal deaths, congenital abnormalities and NICU admissions were not different.