Increases Reported in Certain Birth Defects.

A major analysis of national data on birth defects and the environment has found unexplained increases in certain birth defects and related conditions. The study also noted that nearly 59 million Americans are not covered by birth defects tracking.

Researchers evaluated each state's monitoring effort. One-third of the states, the District of Columbia, and Puerto Rico received "F" grades because they do not currently track birth defects at all. Eight states were awarded "A" grades for systems that could be helpful to future research on the causes of birth defects. The remaining 25 states have tracking systems that are in need of improvements.

Conducted by the Pew Environmental Health Commission at the Johns Hopkins University School of Public Health, the study reported that only about 20 percent of birth defects have known causes, while the causes of the majority await further research. There is, however, increasing evidence that environmental factors, including diet, personal behavior, and exposure to toxic substances and pollutants, may play an important role in the development of birth defects and related conditions.

The researchers concluded that the unanswered questions about wide variations in certain birth defect rates reported over an eight-year period may be the result of improved diagnoses, variations in state tracking procedures, or actual increases.

"What we need is full funding of the Birth Defects Prevention Act of 1998," said Dr. Jennifer L. Howse, president of the March of Dimes and a member of the commission. "This legislation called for more surveillance, research, education, and services to prevent birth defects and protect children, but without full funding, the job just won't get done."

The commission examined data gathered from 1989 to 1996 by the states and by the Centers for Disease Control and Prevention. Among its findings were the following:

* Rates at which babies are born with low birth weights and preterm conditions have been rising steadily since the mid-1980s, despite increased prevention efforts. (Low birth weights and preterm conditions contribute to infant deaths and often accompany birth defects and related conditions such as cerebral palsy and mental retardation.)

* The rate at which infants were born with one serious heart defect rose two and a half times in less than a decade among states that track this defect.

* The rate at which infants were born with a blockage in the urinary tract rose more than one and a half times in less than a decade among states that track this defect.

It is a reflection of the variations in birth defects monitoring systems that researchers found inconsistencies even among the 33 states collecting data.