Monday, July 24, 2006

Evidence in medicine: Preeclampsia

Again on the theme of pregnancy, the July 24 issue of the New Yorker (not available online) contains an article by Jerome Groopman on the "The Preeclampsia Puzzle."Preeclampsia is characterized by high maternal blood pressure and protein in the urine; it can also cause kidney and liver problems, hemorrhage, and stroke. It affects 5% or more of pregnancies in the US, and globally it is a leading cause of maternal death and of lasting complications for mothers and infants.

The cause of preeclampsia is unknown, and the recommended treatment is delivery of the baby ASAP. Although the complex causal pathways that lead up to many diseases are unknown, it is worth pointing out that there is something special about pregnancy disorders: they are not well-studied.

There are several reasons for this. Fetuses cannot consent to participate in clinical trials. Pregnant women, understandably, are not motivated to take on risks to their pregnancy and fetus in order to test new drugs and therapies. Moreover, in some cases, as in preeclampsia, the best available treatment is to deliver the baby, which precludes further testing or treatment in utero.

But if pregnancies are so valuable, shouldn't it be possible to overcome some of these obstacles? Perhaps by running larger trials which permit deeper statistical inferences. But large trials take funding, and this is what the New Yorker article has to say:
Among medical researchers, obstetrics is often regarded as a dead end. "An enterprising young physician-researcher who seeks to make his [sic] name in a field faces huge hurdles if he wants to work with pregnant women"..."Our ability to truly understand what goes on in the fetus is poor," he [Sachs] said. "You can't predict physiologically how a fetus is going to respond to some treatment given to the mother. So people are very hesitant to do this kind of research, and the committees that protoect human subjects are, by and large, gun-shy"..."The only large clinical trials that have been going on involve innocuous treatments, like antioxidants, low-dose aspirin, or supplements like calcium," Sachs said.

Disorders of pregnancy receive relatively little research from the federal government, even though they exact a considerable medical and financial toll.
But it is not just studies of treatments that cannot get off the ground. Even descriptive studies and the development of registries for tracking diseases of pregnancy and post-delivery outcomes are lacking. As with gestational diabetes, the exact rates of preeclampsia in the US are not known, nor are the contributing factors well understood.

The culture of obstetrics is not oriented toward identifying causes that would permit prevention. This is also a relevant topic for feminist bioethics. As Laura Purdy has argued in her article, "What feminism can do for bioethics," bioethicists can and should take on advocacy tasks that shift the way that research is ordered and prioritized.

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