Does diabetes lead to any pregnancy complications?
Women with diabetes are generally followed more closely in pregnancy because of the potential for certain complications. When glucose levels are not in good control, there is also an increased risk for miscarriage and stillbirth.

There is also a higher chance of pre-eclampsia (high blood pressure,  swelling,  and protein in the urine),  pre-term delivery   and   excess   amniotic   fluid   around   the   baby (polyhydramnios).  Finally,  mothers with diabetes are more likely to have large babies, some weighing over 10 pounds.

When this occurs,  the doctor may advise the woman to deliver the baby by cesarean section rather than by vaginal delivery in order to reduce the risk of injuries to the mother and baby. Chances for these complications are lower when women have good glycemic control.
What kinds of tests are recommended during pregnancy for women with diabetes?
There are several tests that can be done during a pregnancy   to   evaluate   how   the   baby   is   growing   and developing.  An ultrasound,  which uses sound waves to create a picture of the baby, can be used to look at different structures of the baby and to make sure the baby is growing at a normal rate.  A fetal echocardiogram can be used to evaluate whether the baby’s heart is developing properly.

Non-stress tests can be used to monitor the baby’s heart rate. A test of maternal blood (called the AFP test or triple screen) measures certain proteins the baby makes that cross into the mother’s blood.  The levels of these proteins can give information on a baby’s chances to have certain birth defects such as spina bifida. 

I have to take insulin injections for my diabetes.  Does insulin have any effects on the baby?
Animal,  human or synthetic insulin may be used for glucose control during pregnancy. Several studies have shown that using insulin during pregnancy is not associated with an increased risk for birth defects. It is thought that the potential benefits of using insulin to regulate glucose outweigh the risks of insulin use,  since better glucose control can reduce the risks of birth defects associated with poorly controlled diabetes.