sPTD | Time of olic acid | Â | Unadjusted | Adjusted1 | ||||
---|---|---|---|---|---|---|---|---|
 | supplementation | n | HR | (CI) | p | HR | (CI) | p |
 | >8 w pre-conceptional | 428 | 1.16 | (1.04–1.30) | 0.01 | 1.16 | (1.02–1.31) | 0.02 |
All | 0-8 w pre-conceptional | 572 | 1.02 | (0.93–1.13) | 0.64 | 1.04 | (0.92–1.17) | 0.52 |
 | 1st trimester | 1185 | 0.94 | (0.84–1.05) | 0.25 | 0.88 | (0.78–0.99) | 0.04 |
 | 2nd trimester | 795 | 1.11 | (1.01–1.23) | 0.03 | 1.10 | (0.99–1.21) | 0.08 |
 | >8 w pre-conceptional | 79 | 1.39 | (1.07–1.80) | 0.01 | 1.34 | (0.99–1.80) | 0.06 |
Early | 0-8 w pre-conceptional | 103 | 1.21 | (0.94–1.55) | 0.13 | 1.18 | (0.88–1.58) | 0.26 |
 | 1st trimester | 199 | 1.07 | (0.81–1.42) | 0.62 | 0.94 | (0.69–1.28) | 0.67 |
 | 2nd trimester | 137 | 1.26 | (0.99–1.60) | 0.06 | 1.18 | (0.91–1.51) | 0.21 |
 | >8 w pre-conceptional | 349 | 1.12 | (0.99–1.27) | 0.07 | 1.13 | (0.98–1.29) | 0.09 |
Late | 0-8 w pre-conceptional | 469 | 0.99 | (0.89–1.11) | 0.88 | 1.01 | (0.89–1.15) | 0.84 |
 | 1st trimester | 986 | 0.91 | (0.81–1.03) | 0.14 | 0.87 | (0.76–0.99) | 0.04 |
 | 2nd trimester | 658 | 1.09 | (0.98–1.21) | 0.13 | 1.08 | (0.97–1.21) | 0.17 |