Plasminogen activators and inhibitors in blood of fetus with good obstetric outcome compared to normal neonates and hydrops fetalis

The fetal coagulation system is an immature developing system and thrombotic complications are not a feature of normal fetal life, possibly the haemostatic system is in dynamic equilibrium. We compared 29 normal fetal blood with 29 normal cord blood from term pregnancy whose mothers had good obstetric outcome and in 10 fetal blood samplings from hydrops fetalis who eventually were stillbirth or aborted for their fibrinolytic and inhibitor status. The gestational age of normal fetus was mean 24 weeks ranging from 22 to 32 weeks and in hydrops, it was mean 27.6 weeks ranging from 20 to 33.7 weeks. The mean results are shown in the table. Significantly shortened reaction and clotting times with enhanced clot formation in normal neonates compared to normal fetal blood were seen using thrombelostography. This was also reflected by elevated systemic t-PA activity, u-PA and plasminogen levels countered by elevated PAI-1 activity. In hydrops fetalis with bad obstetric outcome elevated PAI-1 antigen was seen when compared with normal fetus. Whether PAI-1 could be a marker for prognosis of obstetric outcome in fetal blood sampling especially in hydrops fetalis requires a larger study. t-PA u-PA PAI-1 Plasminogen act(IU/m;) ag(ng/ml) act(IU/ml) ag(ng/mlg) act(AU/ml) ag(ng/ml) % Normal Fetus 0.20 4.99 0.25 0.63 15.0 14,9 29.4 Normal Neonates 2.03*** 6.45 0.56** 1.12* 18.1* 17.4 59'7*** Hydrops 0.16 6,11 0.31 0.82 16.0 23.9** 31.2 act = activity, ag = antigen, * = statistically significant.