Maternal risk factors associated with lead, mercury and cadmium levels in umbilical cord blood, breast milk and newborn hair.

OBJECTIVE

Lead (Pb), mercury (Hg) and cadmium (Cd) are environmental pollutants that are wide spread throughout the world. The present study aimed to investigate the level of exposure to Pb, Hg and Cd during the prenatal period, and the possible routes of maternal exposure to these toxic heavy metals.

PARTICIPANTS

The study included 123 mothers and their newborns. Umbilical cord blood samples were collected immediately after delivery, and breast milk and newborn hair samples were collected between postpartum d 3 and 10.

RESULTS

Among the 121 cord blood samples that were analyzed, Pb was present in 120 (99.2%) and the mean level was 1.66 ± 1.60 µg dL(-1) (range: <detection limit-12.50 µg dL(-1)), whereas Hg was noted in only 2 (1.7%) (15.74 and 33.20 µgL(-1)) and Cd was detected in 24 (19.8%) (range: < detection limit-6.71 µgL(-1)). The level of Pb in cord blood was ≥2 µg dL(-1) in 29% of the samples. Pb, Hg and Cd were detectable in all the newborn hair samples.

DISCUSSION

Among the 107 breast milk samples analyzed, 89 (83.2%) had a detectable level of Pb and the mean level was 14.56 ± 12.13 µgL(-1). Detection rate of Cd in breast milk was higher in women who resided near to city waste disposal site. Detection rate of Cd in cord blood was significantly higher in the women who consumed ≥2 servings of fish weekly. Maternal exposure to environmental tobacco smoke (ETS) resulted in elevated levels of Pb and Cd in newborn hair samples.

CONCLUSION

Most of the study samples had detectable levels of Pb, Hg and Cd, indicating that there was long-term maternal exposure prior to and during pregnancy, and a considerable number of the cord and breast milk samples had levels that exceeded the present accepted safety level.