Effects of exposure to pesticides during pregnancy on placental maturity and weight of newborns: a cross-sectional pilot study in women from the Chihuahua State, Mexico.

It is known that pesticides cross the placental barrier and can cause alterations in the development of placental structures resulting in adverse effects in reproduction. The objectives of this study were to investigate the effects of pesticide exposure during pregnancy on placental maturity and to evaluate the relationship between placental maturity, gestational age and birth weight. We collected the placentas from singleton pregnancies from women exposed (n = 9) and non-exposed (n = 45 full-term and n = 31 preterm) to pesticides as evaluated geographically, by questionnaire and by acetylcholinesterase levels. Placental morphometry from the central and peripheral regions was examined by microscopy and staining with hematoxylin and eosin. The placental maturity index (PMI) was estimated by dividing the number of epithelial plates in terminal villi to their thickness in 1 mm(2) of the placental parenchyma. Gestational age, birth weight and the following characteristics of the mother were also recorded: pre-pregnancy body mass index, weight gain during pregnancy and hemoglobin concentrations. Birth weight and the gestational age were correlated with PMI (r = .54 and r = .44, respectively; p < .01). Pesticide exposure was associated with a higher PMI (beta = 7.38, p = .01) after adjusting by variables related to placental maturity. In conclusion, the results suggest a relationship between prenatal exposure to pesticides and placental maturity and may potentially affect the nutrient transport from the mother to the fetus.