Document Classification

Section Type: RESULTS

Text: Preterm birth rates were 4. 1 % (22/535 low-dose aspirin) and 5. 7 % (31/543 placebo) (relative risk [RR] 0. 72, 95 % confidence interval [CI] 0. 42-1. 23) ; spontaneous preterm birth rates were 1. 1 % (6/535 low-dose aspirin) and 2. 2 % (12/543 placebo) (RR 0. 51, 95 % CI 0. 19-1. 34) ; medically indicated preterm birth rates were 2. 6 % (14/535 low-dose aspirin) and 2. 9 % (16/543 placebo) (RR 0. 89, 95 % CI 0. 44-1. 80).