G. Beroyz et al., CLASP - A RANDOMIZED TRIAL OF LOW-DOSE ASPIRIN FOR THE PREVENTION ANDTREATMENT OF PREECLAMPSIA AMONG 9364 PREGNANT-WOMEN, Lancet, 343(8898), 1994, pp. 619-629
Pre-eclampsia is a common and serious complication of pregnancy that a
ffects both mother and child. Review of previous small trials of antip
latelet therapy, particularly low-dose aspirin, suggested reductions o
f about three-quarters in the incidence of pre-eclampsia and some avoi
dance of intrauterine growth retardation (IUGR), but larger trials hav
e not confirmed these results. In our multicentre study 9364 women wer
e randomly assigned 60 mg aspirin daily or matching placebo. 74% were
entered for prophylaxis of pre-eclampsia, 12% for prophylaxis of IUGR,
12% for treatment of pre-eclampsia, and 3% for treatment of IUGR. Ove
rall, the use of aspirin was associated with a reduction of only 12% i
n the incidence of proteinuric pre-eclampsia, which was not significan
t. Nor was there any significant effect on the incidence of IUGR or of
stillbirth and neonatal death. Aspirin did, however, significantly re
duce the likelihood of preterm delivery (19.7% aspirin vs 22.2% contro
l; absolute reduction of 2.5 [SD 0.9] per 100 women treated; 2p = 0.00
3). There was a significant trend (p = 0.004) towards progressively gr
eater reductions in proteinuric preeclampsia the more preterm the deli
very. Aspirin was not associated with a significant increase in placen
tal haemorrhages or in bleeding during preparation for epidural anaest
hesia, but there was a slight increase in use of blood transfusion aft
er delivery. Low-dose aspirin was generally safe for the fetus and new
born infant, with no evidence of an increased likelihood of bleeding.
Our findings do not support routine prophylactic or therapeutic admini
stration of antiplatelet therapy in pregnancy to all women at increase
d risk of pre-eclampsia or IUGR. Low-dose aspirin may be justified in
women judged to be especially liable to early-onset pre-eclampsia seve
re enough to need very preterm delivery. In such women it seems approp
riate to start low-dose aspirin prophylactically early in the second t
rimester.