Embryolethality and teratogenicity of butyl benzyl phthalate in rats

Pregnant Wistar rats were given butyl benzyl phthalate (BBP) at a dose of 2.0% in the diet on days 0-20, days 0-11 or days 11-20 of pregnancy. Food consumption and body weight gain were decreased in pregnant rats given BBP. Pre-implantation loss in the BBP-treated groups was comparable to that in the control and pair-fed groups. All dams given BBP on days 0-20 or days 0-11 exhibited complete resorption of all the implanted embryos. No increase in post-implantation loss was found in pregnant rats given BBP on days 11-20. Marked teratogenicity was detected in fetuses of the dams given BBP on days 11-20. Cleft palate and fusion of the sternebrae were predominantly observed. Seventy-two of the 134 fetuses had a cleft palate. The incidence of malformations in this group was significantly and markedly higher than that in the control and pair-fed groups. In conclusion, the administration of BBP during the first and second half of pregnancy produced embryolethality and teratogenicity, respectively.