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In utero p,p'-DDE exposure and infant neurodevelopment: a perinatal cohort in Mexico
Luisa Torres-Sánchez1, Stephen J Rothenberg, Lourdes Schnaas
1Instituto Nacional de Salud Pública, Morelos, México.
Insights
Prenatal exposure to p,p'-dichlorodiphenyldichloroethene (DDE) in the first trimester may negatively impact infant psychomotor development. This finding highlights potential risks of developmental delay from DDT metabolites.
Area of Science:
- Environmental health
- Developmental toxicology
- Pediatric neurodevelopment
Background:
- p,p'-dichlorodiphenyldichloroethene (DDE) is a metabolite of DDT.
- Evidence suggests DDE exposure impacts infant neurodevelopment.
- A specific critical exposure window during pregnancy remains unidentified.
Purpose of the Study:
- To identify the critical prenatal exposure window for DDE.
- To assess the impact of prenatal DDE exposure on infant psychomotor development index (PDI) and mental development index (MDI).
- To evaluate neurodevelopmental outcomes during the first year of life.
Main Methods:
- Serum DDE levels were measured pre-pregnancy and throughout gestation in 244 mother-infant pairs.
- Infant psychomotor and mental development were assessed using the Bayley Scales of Infant Development (BSID-II) at 1, 3, 6, and 12 months.
- Statistical analysis utilized generalized mixed-effects models, adjusting for home environment and maternal IQ.
Main Results:
- Third-trimester DDE levels were highest but did not significantly differ from other trimesters.
- First-trimester DDE exposure was significantly associated with reduced PDI (0.5 points per doubled DDE level).
- No significant association was found between DDE exposure and MDI.
Conclusions:
- The first trimester of pregnancy represents a critical window for DDE exposure impacting infant psychomotor development.
- Psychomotor development is a key target for DDE's neurotoxic effects.
- DDT metabolite residues may pose a long-term risk for developmental delays.
Background:
Evidence suggests that p,p'-dichlorodiphenyldichloroethene (DDE) affects neurodevelopment in infants, although a critical exposure window has not yet been identified.
Objectives:
Our goal was to assess the prenatal DDE exposure window and its effect on the psychomotor development index (PDI) and mental development index (MDI) during the first year of life.
Methods:
We recruited 244 children whose pregnancies and deliveries were uncomplicated, and whose mothers were monitored throughout the pregnancy. Participating mothers were not occupationally exposed to DDT (dichlorodiphenyltrichloroethane) but were residents of a zone in Mexico with endemic malaria. We measured serum levels of DDE before pregnancy and during each trimester of the pregnancy. We evaluated PDI and MDI of the Bayley Scales for Infant Development (BSID-II), at 1, 3, 6, and 12 months of age. We adjusted for quality of the home environment and maternal intellectual coefficient (IQ). We used generalized mixed-effects models for statistical analysis.
Results:
Third-trimester DDE level (7.8 +/- 2.8 ppb) was significantly higher than the level at baseline, first, and second trimesters, but the differences never exceeded 20%. Only DDE levels during the first trimester of pregnancy were associated with a significant reduction in PDI (every doubled increase of DDE level reduced the PDI 0.5 points). DDE was not associated with MDI.
Conclusions:
A critical window of exposure to DDE in utero may be the first trimester of the pregnancy, and psychomotor development is a target of this compound. Residues of DDT metabolites may present a risk of developmental delay for years after termination of DDT use.
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