transplacental

As a noun terms

is .

As an adjective transplacental is

(anatomy|physiology) through or across the placenta.

As a noun placenta

is (anatomy) a vascular organ in mammals, except monotremes and marsupials, present only in the female during gestation it supplies food and oxygen from the mother to the foetus, and passes back waste it is implanted in the wall of the uterus and links to the foetus through the umbilical cord it is expelled after birth.

As an adjective transplacental is

(anatomy|physiology) through or across the placenta.