PROTHROMBIN ACTIVITY DURING PREGNANCY AND LACTATION

Abstract

Rats in various stages of pregnancy and lactation were fed standard doses of the hemorrhagic anticoagulant 3,3[image]-methylenebis(4-hydroxycoumarin), and blood samples were taken 24 hrs. later for the detn. of the prothrombin time of 12 1/2% plasma. In pregnant rats the hypoprothrombinemia induced was somewhat milder than that observed in non-pregnant rats. In lactating rats, the change in prothrombin time caused by the anticoagulant was only 18% of that observed in those not lactating. The resistance of the lactating rat appeared to lie in an enhanced capacity to recover from incipient hypoprothrombinemia. By means of foster young, rats were kept lactating for periods up to 180 days. Resistance to the anticoagulant persisted throughout lactation. However, a marked hypoprothrombinemia could be induced during the post-lactation period. When no anticoagulant was fed, plasma from lactating rats contained essentially as much prothrombin as plasma from those not lactating. Recovery from induced hypoprothrombinemia appeared to be related in part to changes in liver wt.