L. Simon et al., PREANESTHETIC ASSESSMENT OF COAGULATION ABNORMALITIES IN OBSTETRIC PATIENTS - USEFULNESS, TIMING AND CLINICAL IMPLICATIONS, British Journal of Anaesthesia, 78(6), 1997, pp. 678-683
The usefulness and optimal timing of laboratory coagulation tests befo
re obstetric extradural analgesia are controversial. Moreover, the sig
nificance of mild coagulation abnormalities during pregnancy remains u
nclear. We have assessed the reliability of coagulation tests performe
d several weeks before delivery as predictors of coagulation abnormali
ties during labour. Platelet count, plasma fibrinogen concentration, p
rothrombin time (PT) and activated partial thromboplastin rime (aPTT)
were sampled in 797 women during the ninth month of pregnancy and chec
ked during labour. Platelet count was less than 100 x 10(9) litre(-1)
for 11 women during labour. Only three had been detected by the first
sample. Platelet count less than 100 x 10(9) litre(-1) or fibrinogen c
oncentration less than 2.9 g litre(-1) during labour were associated w
ith an increase in the incidence of postpartum haemorrhage (odds ratio
= 19.7). We conclude that a platelet count several weeks before deliv
ery was not reliable in predicting thrombocytopenia during labour and
that women with mild coagulation abnormalities in early labour may nee
d special attention regarding the risk of postpartum haemorrhage.