Retinoic acid (RA) plays key roles in pattern  formation along the major

    body axis and vertebrate limb formation. Exposure to excess  retinoic  acid

    in utero  generates  congenital  malformations  in  craniofacial , limbs  and

    axial skeleton. The  aim  of   this  study  was to determine, the retinoic acid

    induced limb malformations in  mouse embryo and its  effect on maternal

    blood.

          In   this   study   NMRI   mice   were  administered by 100 mg/kg  RA  on

    day 9,10   and 11 of pregnancy . In day 18 of   pregnancy   embryos  were

    obtained through cesarean  section.  Maternal   blood  was  examined for

    hematological   studies .  Embryos  were  studied  in  the  case   of skeletal

    elements and histological preparations.

         The results   demonstrate  that 9  days   embryos   carry   37.1%  forelimb

    defects and 31.4% hindlimb defects and 100% of 10 and 11 days  embryos

    show  limb  defects .  These  defects  include   shortened  or   bent   limbs ,

    absence    of   some  long  bones  and  a  wide range  of  digital  defects.

    Hematological   studies  indicated   that   amounts  of   hemoglobin    and

    hematocrit as well as number of red and white blood cells were reduced

    (p<0.05).

         Therefore ,  present  defects  indicated  that  pregnant  women  should

    take    care   for   using   retinoic   acid , specially   during  first   trimester of

    pregnancy.