Reduced spontaneous platelet aggregation: a novel risk factor for adverse pregnancy outcome

ObjectiveSpontaneous platelet aggregation has not been adequately assessed as a potential risk factor for adverse outcomes in pregnancy. Therefore the objective of this study was to assess spontaneous platelet aggregation (SPA), measured via a novel functional assay, as a risk factor for hypertensive disease and intra-uterine growth restriction (IUGR).Study designThis was a prospective longitudinal study. Spontaneous platelet aggregation was assessed as a marker of platelet reactivity using a modification of light transmission aggregometry. Platelet reactivity was assessed in four groups: non-pregnant healthy female volunteers (n = 30), longitudinally in normal uncomplicated pregnancy (n = 50), hypertensive disorder (n = 40) and IUGR (n = 30). The mean percentage SPA was plotted and compared across all groups.ResultsSpontaneous platelet aggregation was significantly reduced in the first trimester compared to the non-pregnant group (p-value = 0.003). The mean aggregation for the hypertensive group was 1.9%, (95% CI −0.08 to 4.02) and for the IUGR group was 1.6%, (95% CI −0.6 to 3.72). Platelet aggregation in the hypertensive group was significantly reduced compared to the normal pregnant group (p < 0.05). Spontaneous platelet aggregation was also reduced in the IUGR group compared to normal pregnancy (p < 0.05).ConclusionThis study demonstrates that a reduction of spontaneous platelet aggregation may be a novel risk factor for adverse pregnancy outcomes such as pre-eclampsia and IUGR. The most clinically significant finding is that SPA is significantly lower in pregnancies complicated by hypertension and IUGR compared to those who had a normal pregnancy outcome. Further studies should be carried out to asses if spontaneous platelet aggregation may be a clinically useful tool for the prediction of pre-eclampsia and IUGR.