Key Infant Mortality Factor Rises After 10-Year Decline

WASHINGTON — The incidence of low birth weight among U.S. newborns, considered a critical indicator of infant mortality, is increasing after a 10-year decline, particularly among black babies, federal health officials said Thursday.

CDC officials attributed the trend to fewer women receiving early prenatal care and said there could be an association with crack cocaine use.

“Studies have shown that cocaine is a risk factor for low birth weight, and there has certainly been an increase in illicit drug use,” said Carol J. R. Hogue, director of the reproductive health division of the Centers for Disease Control.

The incidence of babies born weighing less than 5 1/2 pounds increased 2.2% between 1985 and 1987 after declining 9% from 1975 to 1985, according to the Centers for Disease Control.

In 1987, the latest year for which figures are available, 69 of every 1,000 live newborns weighed less than 5 1/2 pounds, compared with 67.5 in 1985 and 73.9 a decade earlier, CDC reported.

“The reversal of the trend is very important, since prior to this there had been a consistent decline,” Hogue said. “A deterioration in our birth weight distribution means continued slippage in our international (infant mortality) standing, which indicates to me that we need to change what we’re doing.”

The rate of newborns with “very low birth weight” of less than 3 1/4 pounds also rose, the agency said. In 1987, 12.4 of every 1,000 newborns were so classified, compared with 11.6 in 1975.

Although the overall incidence of low birth weight fell from 1975 through 1987 for both white and black infants, the decline was much greater for white newborns, the agency said. In 1987, 127.1 of every 1,000 black newborns weighed less than 5 1/2 pounds, compared with 56.8 for whites.

But the incidence of very low birth weight increased for both groups, rising to 9.2 per 1,000 among white infants and 27.3 among blacks, CDC said.

The CDC, in its report, said the data “underscore the substantial and persistent difference between black and white infants in the risk for low birth weight. Reasons for the worsening gap between the rates for black and white . . . infants are complex.”

Among the reasons, the agency said, are that more black women are poor, single, under the age of 20, undereducated or lacking proper prenatal care--all considered high risk factors in bearing low birth weight babies.

“We need to provide pre-conception counseling to reduce unintended pregnancies, increase healthy behaviors and assure that women, when they become pregnant, receive early and comprehensive prenatal care,” Hogue said.

Although very low birth weight babies are less than 2% of all births, Hogue said they make up a “very large proportion” of deaths during the first year of life. “They are much more likely to die than babies who weigh 6 pounds or more,” she noted.

About 93% of the very low birth weight babies are premature, she said.

CDC’s findings were based on an analysis of birth certificate data provided by the 50 states and the District of Columbia to CDC’s National Center for Health Statistics, the agency said. The data included birth weight and related demographic and health information for the mother and infant.