Maternal serum thromboxane B2 reduction versus pregnancy outcome in a low-dose aspirin trial

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      Objective: Our purpose was to determine whether in a low-dose aspirin trial a longitudinal decrease in maternal serum thromboxane B2 is associated with improvement in pregnancy outcomes.
      Study Design: a total of 606 healthy nulliparous women with singleton gestations were randomized at 24 weeks to either 60 mg of aspirin or a placebo. Maternal serum thromboxane B2 was measured at randomization, at 29 to 31 weeks, at 34 to 36 weeks, and at delivery. After delivery, and without knowledge of patient outcome or group assignment, patients were categorized as having had either a longitudinal twofold or greater (≥50%) or less than twofold reduction (<50%) in thromboxane B2 from baseline levels at randomization.
      Results: Of 606 entrants, 92% had sufficient thromboxane B2 determinations to allow categorizatino. Whether patients were assigned to aspirin or placebo, birth weight was significantly greater in women who had a twofold or greater reduction in maternal serum thromboxane B2 levels. When the aspirin and placebo groups were combined, women with a twofold or greater reduction in thromboxane B2 levels had less preeclampsia, 1.9% (Math Eq) versus 5.7% (Math Eq) (p = 0.016), less preterm delivery (5.7% vs 10.7%, p = 0.032), fewer small-for-gestational-age newborns, 9 of 314 (2.95) versus 17 of 244 (7%) (p = 0.023). and a higher mean birth weight, 3314 gm versus 3121 gm(p = 0.0001).
      Conclusion: Women with a twofold or greater longitudinal reduction in maternal serum thromboxane B2 had less preeclampsia and prematurity, fewer small-for-gestational-age newborns, and higher birth weights than women with less than a twofold reduction.


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        • Wallenburg HCS
        • Dekker GA
        • Makovitz JW
        • Rotmans P
        Low-dose aspirin prevents pregnancy-induced hypertension and preeclamspi in angiotensin-sensitive primigravidae.
        Lancet. 1986; 1: 1-3
        • Schiff E
        • Peleg E
        • Goldenberg M
        • et al.
        The use of aspirin to prevent pregnancy-induced hypertension and lower the ration of thromboxane A2 to prostacyclin in relatively high risk pregnancies.
        N Engl J Med. 1989; 321: 351-356
        • Beaufils M
        • Uzan S
        • Donsimoni R
        • Colau JC
        Prevention of preeclampsia by early aniplatelet therapy.
        Lancent. 1985; 1: 840-842
        • Uzan S
        • Beaufils M
        • Breart G
        • Bazin B
        • Capitant C
        • Paris J
        Prevention of fetal growth retardation with low-dose aspirin: findings of the EPREDA trial.
        Lancet. 1991; 337: 1427-1431
        • Italian Study of Aspirin in Pregnancy
        Low-dose aspirin in prevention and treatment of intrauterine growth retardation and pregnancy-induced hypertension.
        Lancet. 1993; 341: 396-400
        • Hauth JC
        • Goldenberg RL
        • Parker Jr, CR
        • et al.
        Low-dose aspirin therapy to prevent preeclamspia.
        Am J Obstet Gynecol. 1993; 168: 1083-1093
        • Sibai BM
        • Caritis SN
        • Thom E
        • et al.
        Prevention of preeclampsia with low-dose aspirin in healthy, nulliparous pregnant women.
        New Engl J Med. 1993; 329: 1213-1218
        • CLASP (Collaborative Low-Dose Aspirin Study in Pregnancy) Collaborative Group
        CLASP: a randomised trial of low-dose aspirin for the prevention and treatment of preeclampsia among 9364 women.
        Lancet. 1994; 343: 619-629
        • Brown CEL
        • Gant NF
        • Cox K
        • Spitz B
        • Rosenfeld CR
        • Magness RR
        Low-dose aspirin, II: relationship of angiotensin II pressor responses, circulating eicosanoids, and pregnancy outcome.
        Am J Obstet Gynecol. 1990; 163: 1853-1861
        • Hoogendijk EM
        • ten Cate JW
        Aspirin and platelets.
        Lancet. 1980; 1: 93-94
        • Gant NF
        • Daley GL
        • Chand S
        • Whalley PJ
        • MacDonald PC
        A study of angiotensin II pressor response throughout primigravid pregnancy.
        J Clin Invest. 1973; 52: 2682-2689
        • Everett RB
        • Worley RJ
        • MacDonald PC
        • Gant NF
        Effect of prostaglandin synthetase inhibitors on pressor response to angiotensin II in human pregnancy.
        J Clin Endocrinol Metab. 1978; 46: 1007-1010
        • Sanchez-Ramos L
        • O'Sullivan MJ
        • Garrido-Calderon J
        Effect of low-dose aspirin on angiotensin II pressor response in human pregnancy.
        Am J Obstet Gynecol. 1987; 156: 193-194
        • Spitz B
        • Magness RR
        • Cox SM
        • Brown CEL
        • Rosenfeld CR
        • Gant NF
        Low-dose aspirin; I: effect on angiotensin II pressor responses and blood prostaglandin concentrations in pregnant women senstive to angiotensin II.
        Am J Obstet Gynecol. 1988; 159: 1035-1043
        • Sibai BM
        • Mirro R
        • Chesney CM
        • Leffler C
        Low-dose aspirin in pregnancy.
        Obstet Gynecol. 1989; 74: 551-557
        • Masotti G
        • Galanti G
        • Poggesi I
        • Abbate R
        • Serneri GG
        Differential inhibition of prostacyclin production and platelet aggregation by aspirin.
        Lancet. 1979; 2: 1213-1217
        • Ylikorkala O
        • Mäkilä UM
        • Kääpä P
        • Viinikka L
        Maternal ingestion of acetylsalicylic acid inhibits fetal and neonatal prostacyclin and thromboxane in humans.
        Am J Obstet Gynecol. 1986; 155: 345-349
        • Walsh SW
        Preeclampsia: an imbalance in placental prostacyclin and thromboxane production.
        Am J Obstet Gynecol. 1985; 152: 335-340