COAGULATION-FACTOR-13 IN PREGNANT SMOKERS AND NONSMOKERS

Human blood coagulation factor XIII is a transglutaminase zymogen. Two forms exist, an extracellular or plasma factor XIII and an intracellu lar form. Factor XIII occurs in platelets, blood, monocytes, megakaryo cytes, the liver, the placenta, and the uterus. In obstetrics, factor XIII deficiency has been associated with fetal wastage. The interactio n of smoking and the quantity of coagulation factor XIII during normal pregnancy was examined in 75 nonsmoking and 118 smoking (greater than or equal to 20 cigarettes/day) women. A group of subjectively healthy , non-smoking age-matched females served as a control group (n=30). Sm okers had a higher plasma concentration of factor XIII than non-smoker s. Factor XIII declined during normal gestation. During the second hal f of gestation the plasma concentration of factor XIII was significant ly higher in smokers than in nonsmokers. In smokers the decline of fac tor XIII was less, possibly due to platelet activation and a relative polycythemia. The later decline of factor XIII in pregnant smokers rem ains unexplained. More extensive research with larger patient numbers is needed to address this matter.