Moms' high hemoglobin levels linked to stillbirths

Tuesday, November 21st 2000, 12:00 am

By: News On 6

CHICAGO (AP) _ Women with high levels of hemoglobin in their blood early in pregnancy run an increased risk of stillbirths, a study suggests, offering a possible clue to a tragedy that often has no known cause.

In a Swedish study of 1,400 pregnant women, those with high hemoglobin levels early on faced nearly double the risk of having a stillborn child, which means a fetus delivered dead more than five months into pregnancy.

High levels of hemoglobin _ an oxygen-carrying protein that gives red blood cells pigment _ can be caused by smoking, which also has been linked to stillbirths. But this study found no clear association between smoking and hemoglobin and lacked data on what caused participants' high levels.

Other causes of hemoglobin can include heart defects and an overdose of iron supplements.

The findings, from Dr. Olof Stephansson and colleagues at the Karolinska Institute in Stockholm, were published in Wednesday's Journal of the American Medical Association.

Problems with the placenta and birth defects are among causes of the estimated 250,000 U.S. stillbirths each year, but in more than 80,000 cases, the causes are unknown.

The findings suggest that closely monitoring pregnant women with high hemoglobin levels could help prevent some of those deaths, said Dr. Nancy Green, associate medical director of the March of Dimes.

There is no treatment for many cases of high hemoglobin, but such women could be watched more carefully, and if there were signs that the fetus was in trouble, doctors could induce labor or take other steps.

Blood containing too much hemoglobin tends to be sticky and less able to flow through tiny blood vessels. That might disrupt blood flow to the placenta or developing fetus, Green said.