October 9, 2003
Question from Overland Park, Kansas, USA:
I am 31 weeks pregnant and I have gestational diabetes managed with diet and exercise only, and for the most part, my numbers are normal. Ultrasounds have shown the baby to be right about at the size he should be for gestational age. However, I had gestational diabetes last time and was induced at 40 weeks but had to have a C-section. I would like to try for a vaginal birth this time, but of course the diagnosis of gestational diabetes makes that more difficult. An induction is not an option due to the increased risk of uterine rupture and my doctor will not give me a straight answer about what my chances may be if all continues status quo. I’m sure he does not want any answer to come back at him if the end result doesn’t match something he’s said.
A natural and vaginal childbirth is very important to me (as long as it does not interfere with the health of my baby of course) but I would like the opportunity to prepare myself if I am just fooling myself by believing I have a shot. What, if any, statistics are there for women with gestational diabetes being allowed to go into labor by themselves? Can women with gestational diabetes deliver a baby vaginally?
The chance of success with a vaginal birth after Cesarean section depends on the indication for the previous Cesarean section. If it was for a nonrecurring event such as fetal distress or a breech presentation then the success rate is about 75%. If it was for failure to progress in labor, then the success rate drops to about 50%. Interesting though is that I have delivered vaginally babies that were larger than the one that required a Cesarean. This shows that there is more to delivery than just the size of the baby.
Diabetes raises the additional risk of a shoulder dystocia (the head delivers but the rest of the body gets stuck). This can sometimes be managed without any injury to the baby but can also lead to nerve injury or very rarely even death of the baby. The risk of uterine rupture is small (about 1%) but definitely greater than someone who has never had a Cesarean section.
You are more likely to deliver vaginally if you go into labor on your own (unless you go way past your due date). If gestational diabetes requires only diet, then the recommendation is to allow the pregnancy to go to term. However, most doctors would not let you go past your due date. If insulin is required, then most doctors would plan an induction after about 37-38 weeks with documentation of lung maturity. An induction of labor does have an increased risk of ending in a Cesarean section. In general, gestational diabetes carries a higher risk of Cesarean section depending on the size of the baby and in particular the growth of the fetal abdomen.