A LONGITUDINAL-STUDY OF THE FACTOR-VII RISE DURING PREGNANCY

A longitudinal study of 21 pregnant women has been undertaken using a variety of factor VII assays, including factor VIIa, to investigate th e increase of factor VIIc. All assays demonstrated significant rises ( p <0.001), most marked for factor VIIa (82%) and factor VIIc rabbit (8 1%). Smaller rises were seen for factor VIIc bovine (50%) and VII anti gen (40%). Three indirect measures of activity state, factor VIIc rabb it:antigen, bovine:antigen and bovine:rabbit provided conflicting data . Factor VIIa:antigen showed a significant increase of 36% (p <0.001). Within individual pregnancies the change in factor VIIc rabbit and an tigen correlated with maternal weight gain (p <0.05). Two activity sta te measures, bovine:rabbit and bovine:antigen, showed negative correla tion with birthweight. The increases in both zymogen and in activity s tate appear to contribute to the factor VIIc rise. The extent of this rise appears to be influenced by maternal weight gain. Increased facto r VII activation is associated with reduced foetal growth.