TY - JOUR T1 - A cross-sectional study comparing D-Dimer levels from first trimester to day 2 post partum in low risk pregnancies JF - Archives of Disease in Childhood - Fetal and Neonatal Edition JO - Arch Dis Child Fetal Neonatal Ed SP - Fa39 LP - Fa39 DO - 10.1136/adc.2010.189753.20 VL - 95 IS - Suppl 1 AU - N Murphy AU - B Wallace AU - D Broadhurst AU - A Khashan AU - O Gilligan AU - L Kenny AU - K O'Donoghue Y1 - 2010/06/01 UR - http://fn.bmj.com/content/95/Suppl_1/Fa39.1.abstract N2 - D-Dimer measurement is a highly recognised test to exclude venous thromboembolism (VTE). However, during pregnancy D-Dimer levels increase significantly, making diagnosis of VTE using the recommended non-pregnancy cut-off point ineffectual. The aim of this cross-sectional study was to establish reference values for D-Dimers in both the first trimester of normal pregnancy and for women day 2 post partum; thus assisting them to develop effective cut-off values for accurately predicting VTE during/postpregnancy. D-Dimer measurements were carried out on 164 low risk women carrying singleton pregnancy in their first trimester, and 147 women day 2 post partum who gave birth at term. Samples were analysed using Bio-pool Auto-Dimer Assay. Both sample populations were selected using the same exclusion criteria for low risk pregnancy outcome. The results showed that there was a significant difference in mean D-Dimer values between the two populations. This supported previous studies that have shown an increase in D-Dimer levels during normal pregnancy. Importantly, the post partum data show that D-Dimer levels remain high in the 48 h period after delivery. Analysis of the population distributions (table below) shows that the D-Dimer 95th percentile diagnostic cut-off point for normal non-pregnant women (224 ng/ml) is not applicable at either pregnancy time-point. The results also suggest that the cut-off point will increase throughout pregnancy. PeriodMedian5th percentile95th percentile/cut-off*Pregnant <12-week gestation (n=164)10139499Day 2 post partum (n=147)4802001389↵* The recommended non-pregnancy D-Dimer cut-off level for the Bio-pool Auto-Dimer Assay is 224 ng/ml. ER -