Women with albuminuria, a condition marked by abnormal levels of the protein albumin in the urine, are several times more likely to give birth prematurely. These findings suggest that a simple, inexpensive test for urinary albumin may help doctors target their efforts towards women most at risk of delivering early, according to a study released this month in the American Journal of Kidney Diseases, the official journal of the National Kidney Foundation.

"Research suggests that albuminuria may be a sign that a woman has problems in the lining of her blood vessels," says Dr. David Warnock, President, National Kidney Foundation and Director of Nephrology at the University of Alabama at Birmingham. "If so, some cases of prematurity may be caused by a dysfunction in the blood vessels supporting a fetus-a finding that may point to new, future treatments that help babies stay longer in the womb."

Albuminuria is the first sign of kidney disease, when damage to the kidney causes the protein albumin to leak into the urine. Recent research has suggested that people with albuminuria may also be at higher risk of stroke, heart attack and heart failure, perhaps because albuminuria serves as a sign of overall blood vessel problems. In pregnancy, blood vessel problems may disrupt fetal growth and trigger a premature delivery.

Doctors measure albuminuria using a specific urine test, either with a single urine specimen or urine collected over a 24-hour period.

During the study, the investigators measured albumin levels in the urine of 111 women who gave birth to babies after less than 37 weeks' gestation, and 293 women who carried their babies to term.

They found that women with relatively slight increases in the amount of albumin in their urine were nearly twice as likely to have premature babies as women with lower levels of albumin. Women showed an increased risk of premature delivery even when their albumin fell within the normal range for non-pregnant women.

And the more albumin women had in their urine, the higher their chances of giving birth prematurely - indeed, women with the most albumin in their urine were nearly five times more likely than women with the least amount of albumin to have premature babies.

"If we know which mothers are most at risk of delivering early, we can target our efforts to the women who need it most," says Warnock. "Tracking urinary albumin looks like one way we can do that."

The National Kidney Foundation is a major voluntary health organization, which seeks to prevent kidney and urinary tract diseases, improve the health and well-being of individuals and families affected by these diseases, and increase the availability of all organs for transplantation.

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