City's infant mortality rate is up by 26%

But officials say increase likely a statistical illusion

July 15, 2004|By David Kohn | David Kohn,SUN STAFF

A year after falling to its lowest level ever, Baltimore's infant mortality rate rose by 26 percent last year, according to preliminary state health department figures. The rate climbed to 13.1 deaths per 1,000 births, from 10.4 deaths per 1,000 the previous year.

But Baltimore's health commissioner and outside researchers said the increase was probably a statistical illusion caused by a growing tendency to categorize fetal death or pregnancy loss as the death of an infant.

"We think a lot of this is classification," said Dr. Peter L. Beilenson, the city's top health official. "It's a definitional issue."

Some health officials say the confusion lies in the line separating a fetus from an infant. Fetuses that die early in pregnancy are categorized as fetal deaths. But with advances in medical technology, doctors are delivering more extremely premature fetuses with severe medical problems. If a fetus is born and shows signs of life -- a heartbeat or a breath -- it automatically becomes a "viable" infant, even if it dies within hours, officials said. These cases are increasingly classified as infant mortality deaths.

"We're having more tiny babies that are born alive but die almost immediately," said Meena Abraham, an epidemiologist for MedChi, the state medical society.

In a review of Baltimore's latest infant mortality numbers, Abraham found that the rise in infant mortality corresponded almost exactly to the drop in fetal deaths. "One went up, and one went down, by virtually the same amount," Beilenson said.

When Abraham combined the rates of infant mortality and fetal death, she found the latest numbers were lower than those from the year before: 25.7 deaths per thousand births in 2003, compared with 26.4 in 2002.

Abraham noted that over the past five years, the rate of combined fetal and infant death has been dropping. "If you look at both, we're making steady progress," she said.

The artificial increase in infant mortality might be a national trend. In February, the federal Centers for Disease Control and Prevention announced that for the first time since 1958, the U.S. infant mortality rate rose, from 6.8 per 1,000 births in 2001 to 7.0 the next year. Some researchers attribute the increase, in part, to changing definitions of infant and fetus.

"This phenomenon has been seen in other places," said Bernard Guyer, a professor of child health at the Johns Hopkins Bloomberg School of Public Health. Although he had not seen Baltimore's latest numbers, Guyer said that Beilenson's theory made sense.

Because it has so many causes, infant mortality is a crucial measure of overall public health. In recent years, Baltimore's infant mortality rate has been one of the 10 highest among the nation's cities.

Beilenson, who has made lowering the rate a priority, said a key problem is that more babies are being born prematurely. More than half of the babies who died -- whether fetuses or infants -- were premature, he said.

To lower the number of premature births, the health department this year changed the way it tracks pregnant women, targeting those who have a higher risk for premature labor.

Officials now focus on women with at least one of four key risk factors for premature birth: substance abuse, diabetes or hypertension, sexually transmitted disease, or a history of fetal or infant death.

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