The gentlebirth.org website is provided courtesy of
Ronnie Falcao, LM MS, a homebirth midwife in Mountain View, CA

Placental Defect May Cause PIH/Eclampsia

From: C-reuters@clari.net (Reuter / Joanne Kenen)
Subject: Possible cause of pregnancy complication detected
Organization: Copyright 1997 by Reuters
Date: Wed, 30 Apr 1997 16:21:31 PDT

Pre-eclampsia, which affects 7 percent of first-time mothers, can occur suddenly and send a pregnant woman's blood pressure soaring to dangerously high levels.

It can lead to eclampsia -- seizures that can be fatal. But even when it does not progress to eclampsia, the condition creates a risk of premature birth and of small babies who are at risk of a variety of complications.

In a normal pregnancy, the placenta sends out into the uterine wall finger-like projections of cells, called cytotrophoblasts. They begin to mimic the cells that are found inside blood vessels, and eventually they break down the vessels, allowing the mother's blood to bathe the placenta.

This blood carries the oxygen and nutrients that the placenta needs to nourish the fetus, and it carries away waste from the fetus.

But in pre-eclampsia, this process goes awry. The placenta does not invade the uterus adequately and the cells do not manage to mimic blood vessels, the researchers at the University of California at San Francisco said.

This may set off a reaction in the circulatory system that causes the high blood pressure, although the exact mechanism is not precisely understood yet, said Dr. Don McNellis of the National Institute on Child Health and Human Development (NICHHD), which supported the study.

The findings appear in the May 1 edition of the Journal of Clinical Investigation.

McNellis said in a telephone interview the finding is a major advance in understanding the condition although more research was needed in order to translate the cellular findings to therapies, prevention or better diagnostic tools.

``This might not explain all cases (of pre-eclampsia) but we believe a significant proportion is associated with this,'' McNellis said.

Pathologists had identified the problem with the placenta in earlier studies but ``it was not understood. Now it has been described by Dr. Fisher in terms of cell biology that can explain the mechanism,'' he added.