This review addresses the Lacrosse Goggle function of the protein-transporter glycoprotein-P (Pgp, ABCB1 protein) and the expression of its encoding gene MDR1/mdr1 throughout the gestational period in humans and animals.We discuss the relationship between the transporter function and the hormone fluctuations during pregnancy.We cite studies on the association between the MDR1/mdr1 gene polymorphisms and the hemato-placental barrier permeability for Pgp substrates, as well as fetal malformations.Under a separate section, drugs commonly used in pregnant women are characterized in terms of their roles as Capacitor substrates, inducers or inhibitors of the Pgp transporter.