I just had a baby. While pregnant, my "perinatologist" took me off metformin as he said that is the general rule of thumb due to increase of blood sugar in pregnancy and wild fluctuation in control which I experienced. I d o not particularly like "shots" but for my safety and that of the baby as my doc said -" baby could get dangerously big if sugar is not controlled adequately and the risk of still born becomes high", I had to take shots of lantus and regular insulin.
I suggest you consult with your physician on this again and plan appropriately. As a diabetic, I was monitored more frequently than normal - more ultrasound to determine viability of baby, growth etc. Baby was electively born by C/S as he was in the 98th percentile of his weight in the 37th week. So speak with your doc.
"but there has never been any study of the drug in pg women that I could find."
This article talks about several.....
http://care.diabetesjournals.org/cgi/content/full/30/11/2980
As pregnancy progresses and placental growth continues, it causes up to a 30% increase in maternal insulin needs. So if the blood sugar goes up, it is much easier (and quicker) to bring it down by adjusting the insulin dose than by adjusting an oral medication dose.
Here's a good article from 2007 that compares the use of oral diabetes meds and insulin during pregnancy......
http://care.diabetesjournals.org/cgi/content/full/30/11/2980
"Safety of oral hypoglycemic agents in pregnant women.
Coustan outlined the guiding principles that any clinician should consider before using pharmacological agents in pregnancy. Safety for mother and fetus are paramount, and the benefits must obviously outweigh the risks. A key consideration is whether the substance crosses the placenta and, if it crosses, whether it will harm the fetus. Insomuch as oral hypoglycemic agents (OHAs) can normalize the hyperglycemia that harms the fetus, they must be beneficial. However, sulfonylureas stimulate insulin secretion from the fetal beta cells, thereby potentially INCREASING THE HARMFUL hyperinsulinemic effects in the fetus caused by hyperglycemia. "
The authors suggest that Glyburide.... "is a clinically effective alternative to insulin. However, the failure rate for glyburide treatment was 20%. with the highest prevalence of large-for-gestational-age infants (22%)"
And that oral diabetes meds......"should be seriously considered where diabetes educators are a rare resource, where insulin is expensive or not available, and where low levels of literacy make it difficult to explain the intricacies of using insulin appropriately."
I think the reason that some doctors keep patients on glyburide during pg is because many women will balk at 2 or 3 injections a day and may skip the insulin. They feel this is more dangerous than unknown possible risks from glyburide. I have read that glyburide is considered very safe in the 2nd and 3rd trimesters but there has never been any study of the drug in pg women that I could find. If it makes you feel better, go ahead and ask your surrogate if she would switch to insulin at least for a month or two. That will give the babies time to finish all of those early developments that can be so sensitive. Try to relax, even though you feel out of control. If your surrogate is willing to use insulin, I don't see why her dr would object to the switch. Good Luck!
As far as I know all pregnant women are taken off their oral diabetes medication and put on insulin for the duration of the pregnancy.