Document Classification

Section Type: RESULTS

Text: Relative risks (95 % CI) for spontaneous preterm delivery before 37 weeks were 3. 8 (2. 6, 5. 6), 5. 4 (3. 3, 9. 0), and 6. 3 (3. 0, 13. 0) for the tenth, fifth, and two and a half percentiles, respectively ; RRs for before 35 weeks were 4. 5 (2. 9, 6. 9), 7. 5 (4. 5, 12. 5), and 7. 8 (3. 6, 16. 7) ; and for before 32 weeks were 5. 2 (3. 3, 8. 3), 9. 7 (5. 8, 16. 1), and 8. 4 (3. 6, 19. 9), respectively.