The effect of low-dose aspirin on pregnancies complicated by elevated human chorionic gonadotropin levels,

OBJECTIVE: Our purpose was to determine whether elevated second-trimester human chorionic gonadotropin levels identify women likely to benefit from low-dose aspirin therapy. STUDY DESIGN: We evaluated second-trimester human chorionic gonadotropin levels obtained from healthy nulliparous women before screening for participation in a double-blind randomized trial of aspirin therapy: 262 women took 60 mg of aspirin daily and 420 did not. RESULTS: Among women who did not take aspirin, those with human chorionic gonadotropin levels ≥2.0 multiples of the median had a significantly lower mean birth weight (2859 vs 3159 gm, p = 0.04) than did those with normal human chorionic gonadotropin levels. All women who took aspirin had a higher mean birth weight than women whodid not, but women with human chorionic gonadotropin levels ≥2.0 multiples of the median had the greatest increase (416.2 gm higher in those with human chorionic gonadotropin levels ≥2.0 multiples of the median, p = 0.02; 96 gm higher in those with human chorionic gonadotropin levels <2.0 multiples of the median, p = 0.04). Regression analysis suggested that the higher birth weight was partly explained by a higher gestational age at delivery and partly by increased weight independent of gestational age. CONCLUSIONS: Aspirin therapy inreased birth weight in all women, especially in women with high human chorionic gonadotropin levels, partly by increasing gestational age at delivery. This observation needs to be confirmed by further studies.