Longnecker, MP, MA Klebanoff, H Zhou, JW Brock. 2001. Association between maternal serum concentration of the DDT metabolite DDE and preterm and small-for-gestational-age babies at birth. The Lancet 358: 110-114.
Longnecker et al. demonstrate a powerful association between DDE levels in mothers' serum and the likelihood of premature birth. The higher the contamination level, the more likely was preterm birth. They also show that contamination is linked to the baby's size, with babies more likely to be small for their gestational age when born to mothers with higher DDE levels.
According to the lead author, in the US in the 1960s there may have been "an epidemic of pre-term births that we are just now discovering."
In the Lancet paper, the authors write that their results
Interviewed by the British science magazine, New Scientist, Dr. Matthew Longnecker (US National Institute of Environmental Health Sciences), the lead author of the report, estimated that DDT use in the United States could have been responsible for as much as 15% of infant deaths during the 1960s.
did they do?
Longnecker et al. measured concentrations of p,p'-DDT and p,p'-DDE in serum samples taken from the pregnant mothers. They then evaluated the DDE concentrations in relation to the chances of a pre-term birth and infant size (controlling for gestational age).
What did they find?
does this mean?
DDE blood levels in the US are now well beneath those concentrations detected in this study (made of blood samples obtained in 1959-1966) and beneath the apparent threshold for the effect detected in the authors' statistical analysis (10 micrograms/liter). Hence even though DDE contamination persists in people in the US, similar studies today in the US would be unlikely to detect an effect. This is not the case, however, in countries where DDT continues to be used for insect control.
According to the authors:
They go on to observe that "Benefits of vector control with DDT might need to be reassessed in the context of this adverse effect on human beings and the availability of alternative methods of vector management." This is a cautious way of stating that DDT's potential contribution to infant mortality should be factored into decisions about phasing out DDT use, increasing the urgency of finding safe and affordable alternatives.