A fascinating article at the New York Times looks at a new theory of pregnancy as a basic conflict between organisms, an idea advocated by Dr. David Haig, an evolutionary biologist at Harvard.
Here’s a teaser:
Dr. Haig proposed that pre-eclampsia was just an extreme form of a strategy used by all fetuses. The fetuses somehow raised the blood pressure of their mothers so as to drive more blood into the relatively low-pressure placenta. Dr. Haig suggested that pre-eclampsia would be associated with some substance that fetuses injected into their mothers’ bloodstreams. Pre-eclampsia happened when fetuses injected too much of the stuff, perhaps if they were having trouble getting enough nourishment.
In the past few years, Ananth Karumanchi of Harvard Medical School and his colleagues have gathered evidence that suggests Dr. Haig was right. They have found that women with pre-eclampsia had unusually high levels of a protein called soluble fms-like tyrosine kinase 1, or sFlt1 for short.
Other labs have replicated their results. Dr. Karumanchi’s group has done additional work that indicates that this protein interferes with the mother’s ability to repair minor damage to her blood vessels. As that damage builds up, so does her blood pressure. And as Dr. Haig predicted, the protein is produced by the fetus, not the mother.