I am currently and successfully on D4T, Viramune and DDI. I was on AZT monotherapy from 92-94 at 300mg. I am trying to become pregnant and have some concerns about the added benefits of AZT during labor. I have decided that I will not change meds or add AZT given that I am likely resistant and D4T and AZT should not be used together. However, some HIV and OB docs would still like me to have IV AZT during labor claiming that you can still use AZT in labor even if I am on a D4T-containing regimen. What is your opinion on this? Will this make my present regimen less effective during labor? What about skipping the AZT altogether (I am undetectable, VL has never gone above 4000 pre HAART, and I expect to remain undetectable through labor)? And given my history with AZT, what would you suggest for an appropriate regimen for my newborn? I had originally thought a single dose of viramune but have some concerns based on a recent report of mothers who had taken viramune prior to delivery and their newborns not maintaining adequate drug levels in their blood when compared to those who only had nevirapine at delivery. Thanks, Carrie

You have a sophisticated understanding of the issues and have asked some of the key questions. While the guidelines have been fairly rigid in recommending AZT as part of therapy for pregnant women, it has not made a lot of sense for those with resistant virus or serious side effects. At Durban, a study was presented showing that d4T and ddI as monotherapy are equivalent to AZT monotherapy. This confirms that women who have resistance to AZT have other options during pregnancy. So, remaining on your current regimen makes sense. The argument for IV AZT is in part based on the ability to get high blood levels by using it IV. That may or may not add anything if your viral load is very low. Since you are already on nevirapine, there is no reason not to continue it all the way through labor. It is not clear that you have much circulating AZT-resistant virus, so your baby would likely be exposed to sensitive virus. AZT could be reasonably used for the first 6 weeks. The advantage is that the pharmacology is best understood. I would also consider giving your baby a single dose of nevirapine in the first 48 hours of life for post-exposure coverage.

Good luck

Andrew T. Pavia, M.D.