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PRE-ECLAMPSIA, a major cause of death and illness in pregnancy, may have an
Achilles鈥� heel, say British researchers. Their claim follows the discovery of a
biochemical anomaly which could lead to a test early in pregnancy before any
symptoms appear, and even a treatment.

Up to one in ten pregnant women are affected by pre-eclampsia, most often in
the third trimester. The woman鈥檚 blood pressure shoots up, her hands and feet
swell, and she can develop blood clots. The disease can strike without warning,
and in extreme cases causes convulsions and death. Often the only treatment is
to deliver the baby straight away鈥攚hich may mean it is born several weeks
prematurely.

Nobody knows the exact cause of pre-eclampsia but scientists suspect that a
key factor is the way a fetus implants in its mother鈥檚 womb. If this goes wrong
and leaves the baby with a reduced blood supply, the placenta tries to
compensate by sending chemical signals that divert the mother鈥檚 blood away from
other organs by raising her blood pressure in key locations.

To find out how this happens, a team led by Philip Lowry at Reading
University compared placentas from pre-eclampsia patients and women with normal
pregnancies. They focused on a hormone called neurokinin B (NKB), which in
animals is known to make certain blood vessels constrict, causing blood pressure
to rise. It also makes the heart beat faster, and at high levels might affect
blood flow to the brain.

The researchers found that NKB levels were 100 times higher in women with
pre-eclampsia. 鈥淭hose levels are absolutely enormous,鈥� says Lowry. 鈥淲hen I
started looking for where the receptors for this peptide were, they were sitting
in organs and tissues that were tailor-made for causing pre-eclampsia.鈥� Lowry
says a prime example is the presence of NKB receptors in the portal vein, which
carries digested food to the liver. The liver is one of the key organs to be
damaged during pre-eclampsia.

The researchers believe NKB levels can rise early on in problem pregnancies,
and this may make possible a blood test to identify women at risk. Lowry notes
that there are already drugs that could be used to block the hormone鈥檚
receptor.

This is 鈥渁 very substantial finding鈥�, says Christopher Redman, Professor of
Obstetric Medicine at Oxford University. But he adds: 鈥淚 would very much doubt
that it is the one and only cause of the problem.鈥�