Elevation in D-dimer concentrations is positively correlated with gestation in normal uncomplicated pregnancy

Abstract

Background: D-dimer levels have been reported to increase progressively during pregnancy, but how this affects Nigerian women is not well known.

Objective: This study aims to determine the D-dimer concentration and its relationship to other coagulation parameters among pregnant women in Port Harcourt, Nigeria.

Method: In a cross-sectional observational study conducted in Port Harcourt, Nigeria, 120 pregnant women and 60 nonpregnant controls, drawn from a tertiary health institution in the Niger Delta, Nigeria, were assessed, using the standard procedures, for the following parameters: D-dimer concentration, prothrombin time, activated partial thromboplastin time, platelet count, hemoglobin, and packed cell volume.

Results: The median D-dimer concentration of 153.1 ng/mL in the pregnant group was found to be significantly elevated when compared with the control value of 118.5 ng/mL (t = 2.348, P = 0.021). Conversely, there was a marked depression in the platelet count among pregnant women (193.5 × 10(9)/L) when compared with 229.0 × 10(9)/L in the control group (t = 3.424; P = 0.001). There was no statistically significant difference in the values for the prothrombin time and the activated partial thromboplastin time between pregnant and nonpregnant women. D-dimer values correlated positively and significantly with gestation (r = 0.36; P < 0.01) and negatively with international normalized ratio values (r = -0.281; P < 0.05). About 63.3% of the pregnant women had normal D-dimer values (0-200 ng/mL), 26.7% of the pregnant women had elevated D-dimer levels (201-499 ng/mL), while 10.0% of the pregnant women were found to be at risk of thrombosis (D-dimer > 500 ng/mL). A linear relationship was found to exist between D-dimer and gestation (y = 8.355x + 36.55; R(2) = 0.130; P < 0.005).

Conclusion: 10% of the pregnant women in this population had elevated D-dimer levels over 500 ng/mL, and through comparison with what has been reported in the literature, there is the possibility that this group may be at risk of thrombosis. Further studies, incorporating other diagnostic parameters, may be needed before a more logical conclusion can be drawn, since the D-dimer is not a specific test.

Keywords: D-dimer; Nigeria; activated partial thromboplastin time; pregnancy; prothrombin time.

Figure 1

Relationship between trimesters and D-dimer values of the pregnant women.

Figure 2

Relationship between gestation and D-dimer values of the pregnant women.

Figure 3

Relationship between age and D-dimer values of the nonpregnant controls.