- placental barrier n a semipermeable membrane made up of placental tissues and limiting the kind and amount of material exchanged between mother and fetus <thiazides cross the placental barrier and appear in cord blood (Resident & Staff Physician)>
* * *the placental separation of fetal from maternal blood and bloodborne materials of greater than molecular size; in humans the term placental membrane is preferred, because it is not a barrier to most substances in the maternal blood, such as drugs and viruses.
Medical dictionary. 2011.
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placental barrier — noun : a semipermeable membrane made up of placental tissues and limiting the character and amount of material exchanged between mother and fetus … Useful english dictionary
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