SMFM 27th Annual Meeting 2007
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Alix Boyle: Hi, this is Alix Boyle reporting for OBGYN.net. We are here with Dr. Steve Caritis from the University of Pittsburgh, Magee Women’s Hospital. Tell us about your research.
Steve Caritis, MD: We presented the results of our study at this meeting, the Society for Maternal Fetal Medicine. The objective of our study was to compare the benefit of 17 hydroxy-progesterone caproate with placebo in prolonging pregnancy in twin gestation.
Alix Boyle: Why did you study twins?
Steve Caritis, MD: The original study that showed a benefit of 17 hydroxyprogesterone caproate in recent literature was that published by Dr. Paul Meis as part of the Maternal Fetal Medicine Network Units. That study showed that 17 hydroxyprogesterone caproate, which I’ll just call caproate for this presentation, that caproate when administered to women at high risk reduced their risk of recurrent pre-term birth by one-third. The criterion for defining high risk was a woman who had delivered prematurely previously. So the medication showed substantial benefit in that population so the question we asked was, are there other high risk populations that might benefit from this treatment? One high risk population in terms of delivering prematurely is clearly multi-fetal gestation, so twin gestation in particular is at an increased risk of pre-term birth so we questioned whether this therapy might be useful in that group of patients.
Alix Boyle: Did it matter whether the twins were mono or dichorionic?
Steve Caritis, MD: Well, what we found from this study was the opposite of the findings we found for the singleton pregnancies that were reported by Dr. Meis. We found that the treatment with caproate did not reduce the pre-term birth rate among twins. Now that lack of benefit existed whether we looked at monochorionic or dichorionic placentation. It also did not make a difference whether we looked at a primary endpoint of 35 weeks or 32 weeks or 28 weeks. So regardless of how we analyzed the data, 17 hydroxyprogesterone caproate did not reduce the pre-term birth rate in twins.
Alix Boyle: Would you use 17-OHPC in women with a prior pre-term twin birth who are now pregnant with a singleton?
Steve Caritis, MD: There is no literature to guide us on this. We know that women who deliver prematurely from a twin gestation in a subsequent gestation are still at increased risk of pre-term birth, so one can argue that treating them with 17 hydroxyprogesterone caproate makes sense because they are a high risk group and caproate does reduce the risk of pre-term birth, at least in some high risk groups. Unfortunately, again, we do not have data to support this approach, but clearly the potential is there that it would be of value. But whether it is or not, only time will tell.