however , in vivo and in vitro experiments with laboratory animals show that pregnancy and lactation elevate maternal bone strontium and depress maternal bone calcium because 1 ) strontium is discriminated against in favor of calcium in the transport of ions to the placenta and mammary glands and 2 ) pregnancy and lactation facilitate absorption of alkaline earth metals from the gut .
C0038467
strontium
C0025555
alkaline earth metals