Objective     To investigate the effects of nordihydroguaiaretic acid (NDGA) on the embryos growth and decidual development in rats.      Methods     Fifty pregnant SD rats were randomly divided into NDGA-treated group（N）and control group (P)

which were given subcutaneous injection of NDGA or PBS on embryonic day 1(E1)

E7 and E14

and then killed on E6 and E9. The number of implantations was calculated

the diameter of the embryos was measured and the numbers and weight of neonates were recorded. The expressions of VE

GF

PCNA and FⅧRAg in the deciduas and embryos were detected by immunohistochemistry and then made image analysis. The serum concentrations of progesterone on E9 were measured.      Results     The number of implantations were decreased with NDGA treatment on E1 (

P

<

0.05)

but were not on E7. The diameter of embryos and weight of neonates were decreased on E1 and E7 (

P

<

0.05). The expressions of VEGF

PCNA and FⅧRAg in the deciduas were all reduced (

P

<

0.05). The serum concentrations of progesterone on E9 had no different from the control Group. In E14 group

the number and weight of neonates showed no difference from the controls.      Conclusion     NDGA can inhibit the growth of early embryo and interfere with the progress of decidualization obviously

but has few effect on the later embryo.