From: Revisiting the association between maternal and offspring preterm birth using a sibling design
 |  | Infant’s PTB cases/No of births | PTB rate, % | (N = 78,922) | (N = 78,922) | (N = 74,196) | (N = 39,478) | ||||
---|---|---|---|---|---|---|---|---|---|---|---|
Offspring outcome | Maternal PTB type | URR | 95% CI | ARRb | 95% CI | ARRc | 95% CI | ARRd | 95% CI | ||
Any PTB | Not Preterm | 4565/75,172 | 6.07 | 1.00 | Reference | 1.00 | Reference | 1.00 | Reference | 1.00 | Reference |
Spontaneous | 195/2165 | 9.01 | 1.48 | 1.29, 1.70 | 1.47 | 1.28, 1.68 | 1.43 | 1.24, 1.65 | 1.28 | 1.03, 1.58 | |
Provider-initiated | 128/1585 | 8.08 | 1.33 | 1.12, 1.57 | 1.29 | 1.09, 1.52 | 1.23 | 1.02, 1.47 | 1.14 | 0.87, 1.48 | |
Spontaneous PTB | Not Preterm | 3164/75,172 | 4.21 | 1.00 | Reference | 1.00 | Reference | 1.00 | Reference | 1.00 | Reference |
Spontaneous | 149/2165 | 6.88 | 1.64 | 1.40, 1.92 | 1.61 | 1.38, 1.89 | 1.57 | 1.32, 1.85 | 1.33 | 1.04, 1.71 | |
Provider-initiated | 93/1585 | 5.87 | 1.39 | 1.14, 1.70 | 1.36 | 1.11, 1.66 | 1.32 | 1.07, 1.64 | 1.09 | 0.78, 1.52 | |
Provider-initiated PTB | Not Preterm | 1401/75,172 | 1.86 | 1.00 | Reference | 1.00 | Reference | 1.00 | Reference | 1.00 | Reference |
Spontaneous | 46/2165 | 2.12 | 1.14 | 0.85, 1.52 | 1.13 | 0.85, 1.52 | 1.11 | 0.82, 1.51 | 1.16 | 0.76, 1.77 | |
Provider-initiated | 35/1585 | 2.21 | 1.18 | 0.85, 1.65 | 1.13 | 0.81, 1.57 | 1.00 | 0.69–1.46 | 1.24 | 0.77, 1.99 |