The pesticide DDTwhich was banned in the U.S. in 1972, but is still used elsewhere todaymay cause premature births, according to a new study published in the current issue of The Lancet. "The findings of our study strongly suggest that DDT use increases pre-term births, which is a major contributor to infant mortality," lead author Matthew Longnecker of the National Institute of Environmental Health Sciences says. Longnecker collaborated with scientists from the National Institute of Child Health and Human Development, as well as from the University of North Carolina at Chapel Hill and the Centers for Disease Control and Prevention.

The team studied samples of blood drawn from women who had given birth between 1959 and 1966 and stored as part of the U.S. Collaborative Perinatal Project, a program of the National Institutes of Health and 12 universities. The scientists selected 44,000 samples and analyzed them for DDE, a breakdown product of DDT. They also had available additional information about 2,380 children from the original study: 361 of these children were born prematurely and 221 were born smaller than usual. As it turned out, the mothers of these children had higher DDE blood levels than other women in the survey. Moreover, the average DDE blood level of all the women was about five times higher than that found today. "DDT levels in the U.S. are now low and likely not causing any harm," Longnecker says. "But we have to be concerned about what might be happening in those 25 countries where DDT is still used. Also, looking back on earlier decades in the U.S., we may have had an epidemic of pre-term births that we are just now discovering."