FETUS GROWTH, MOTHER'S IMMUNE SYSTEM LINKED

                         Roanoke Times
                 Copyright (c) 1995, Landmark Communications, Inc.

DATE: SUNDAY, February 21, 1993                   TAG: 9302210035
SECTION: VIRGINIA                    PAGE: C4   EDITION: METRO 
SOURCE: Associated Press
DATELINE: RICHMOND                                LENGTH: Medium
FETUS GROWTH, MOTHER'S IMMUNE SYSTEM LINKED
Why are some babies born too small, even though their mothers took no added risks and had normal pregnancies? A researcher believes the answer lies in the complex relationship between a woman's immune system and the development of the baby.
Oddly, the pregnant woman's immune system first must try to reject a fetus before the fetus can develop normally, said Scott Kauma, assistant professor of obstetrics and gynecology at the Medical College of Virginia.
"The woman's body recognizes the pregnancy as something foreign, and she produces a substance that is associated with immune rejection - the body gearing up to fight off something," Kauma said.
The chemical substance, called Interleuken-1, actually stimulates fetal growth, Kauma believes. If the woman's body doesn't produce enough of the chemical very early in pregnancy, the placenta does not grow sufficiently, he said.
"The placenta is basically the heart, lungs and liver of the fetus. If the placenta is small, the fetus is going to be small," Kauma said.
Although the woman's body stops trying to reject the fetus quite early in pregnancy, the brief period when the fetus is exposed to Interleuken-1 appears to be key, he said. Without enough of the chemical, the placenta never grows large enough.
Kauma believes that severe lack of Interleuken-1 results in miscarriage, while milder deprivation can produce low birth-weight.
Underweight babies suffer higher mortality rates during their first year of life than normal birth-weight babies, Kauma said. They also run increased risk of mental retardation or developmental delays.
Research in mice seems to have established the immune system link, but further work is needed in humans, he said. Kauma recently received a five-year, $524,000 grant from the National Institutes of Health to study the link.
An immunological link has been identified in research on women who suffer repeated miscarriages, said Mike McClure, head of reproductive sciences at the NIH's Child Health and Human Development branch.
"There is a subset of women . . . in whom there is an immunological factor. The research is aiming at seeing if we can induce the immune system to not cause problems," McClure said.
High blood pressure, smoking, drinking alcohol and taking drugs during pregnancy all are known risk factors for delivering small babies. But Kauma plans to study women who had no known added risks during pregnancy.
Approximately 40 percent of low-birth-weight babies had no known risk, he said. The same percentage is true for miscarriages.
Initially Kauma will look at about 300 women who are patients at MCV, he said. Many of these women had repeated miscarriages or delivered what he terms "small-for-date" babies: children born below normal weight after full-term pregnancies.
About 7 percent of the approximately 3.9 million children born annually in the United States are below normal weight, said Jeff Lancashire at the National Center for Health Statistics. The number of underweight children has not changed significantly in 20 years, he said.
Doctors have few options when they recognize that a child is developing too slowly in the womb, although bed rest and low-dose aspirin appear to help, he said.
Kauma said he hopes his research will lead to a drug that could stimulate the placenta to grow larger in women who do not produce enough Interleuken-1.
Doctors can determine the baby's size by measuring a woman's uterus. If a child is too small, the drug could help compensate before birth.
"That is very far down the road, but we hope it is possible," Kauma said.

by Archana Subramaniam by CNB