Gestational and lactational transfer of melamine following gavage administration of a single dose to rats

Melamine contamination in an infant formula manufactured by a firm in China was reported in September 2008. Maternal transfer of melamine during pregnancy and through breast-feeding are possible ways of introduction. This study aims to evaluate the maternal transfer of melamine into amniotic fluid and breast milk through oral intake by pregnant and lactating rats, respectively. The quantity of melamine in the dam's sera, amniotic fluid, breast milk as well as in fetal whole body extract was measured. Our results showed that, after administration of single dose of 21.4 mg/kg per body weight of melamine to pregnant rats (16-18 days of gestation) by gavage, about 80% of melamine was found in dam's serum in 0.5 h. Melamine further reached the fetuses through placental transfer as it was found that peak melamine level of 7.15 ppm (∼30%) was detected in the fetuses after 2 h and 4.36 ppm (∼20%) was shown in amniotic fluid after 3 h of maternal intake. In the lactating rats, about 40% of maternal intake of melamine was transferred to breast milk and peaked at 3 h. The results of this study confirmed the maternal transfer of melamine to fetuses in utero and infants through breast feeding.