The final stage: Investigating determinants of plasmin generation in the third trimester of pregnancy

Abstract

Background. Changes in the fibrinolytic system that support haemostasis are seen in the third trimester of pregnancy. An imbalance between coagulation and fibrinolysis could increase either thrombotic episodes or haemorrhagic risk.

Objective. To assess plasma D-dimer and plasmin-a2-antiplasmin (PAP) complex levels as indication of plasmin generation during late pregnancy.

Methods. A sample of 41 healthy pregnant women in their third trimester participated in the study. Data on obstetric history, body mass index (BMI) and other demographic variables were recorded. Haematological analysis involved enzyme-linked immunosorbent assaying of venous blood samples. Statistical analysis was performed using SPSS version 21.

Results. Mean maternal and gestational age, with associated standard deviations (SD), were 30.68 (4.69) years and 34.78 (3.34) weeks, respectively. Haematological analysis showed mean (SD) values of D-dimer and PAP complex to be 194 (24 ng/mL) and 175 (11 ng/mL), respectively. Both indicators were positively correlated with maternal age, gestational age and BMI grouping, although significantly only for maternal age. Multiple linear regression analysis showed that with every increasing year of maternal age, D-dimer levels increased by 2.0 ng/mL (95% confidence interval (CI) 0.4 - 3.6 ng/mL). PAP complex levels similarly increased by 0.8 ng/mL (95% CI 0.1 - 1.5 ng/mL), after controlling for gestational age and BMI.

Conclusion. D-dimer and PAP levels increased with increasing maternal age, suggesting it to be an independent determinant of plasmin generation in the third trimester of pregnancy. If this finding is confirmed in larger studies, age should be considered when interpreting these indicator values during pregnancy.