Table 3.
Risk of pre/post term relative to full term by maternal country of birth: 1997–2010 (n = 345,837)
| Gestational age | ANI (n = 231,950) |
AI (n = 20,206) |
FB-LIC (n = 2840) |
FB-LMIC (n = 17,951) |
FB-UMIC (n = 17,452) |
FB-HIC (n = 55,438) |
||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| n | cRRR, (95%CI) | aRRRa (95%CI) | n | cRRR, (95%CI) | aRRRa (95%CI) | n | cRRR, (95%CI) | aRRRa (95%CI) | n | cRRR, (95%CI) | aRRRa (95%CI) | n | cRRR, (95%CI) | aRRRa (95%CI) | n | cRRR, (95%CI) | aRRRa (95%CI) | |
|
Extreme preterm (< 28 weeks) |
1457 | Ref | Ref | 370 | 3.27 (2.91, 3.67) | 2.75 (2.41, 3.14) | 30 | 1.46 (1.02, 2.11) | 1.42 (0.98, 2.04) | 137 | 1.29 (1.08, 1.54) | 1.32 (1.10, 1.57) | 106 | 1.00 (0.82, 1.22) | 1.02 (0.83, 1.24) | 349 | 0.99 (0.88, 1.12) | 0.96 (0.85, 1.08) |
|
Very early preterm (28–32 weeks) |
1269 | Ref | Ref | 321 | 3.26 (2.88, 3.69) | 2.73 (2.37, 3.14) | 25 | 1.40 (0.94, 2.08) | 1.37 (0.92, 2.04) | 121 | 1.31 (1.08, 1.58)) | 1.34 (1.11, 1.62) | 97 | 1.05 (0.85, 1.29) | 1.08 (0.87, 1.33) | 313 | 1.02 (0.90, 1.16) | 0.99 (0.88, 1.13) |
|
Early preterm (32–33 weeks) |
1570 | Ref | Ref | 347 | 2.85 (2.53, 3.20) | 2.59 (2.27, 2.96) | 16 | 0.72 (0.44, 1.19) | 0.71 (0.43, 1.17) | 130 | 1.14 (0.95, 1.36) | 1.16 (0.97, 1.39) | 103 | 0.90 (0.74, 1.10) | 0.91 (0.74, 1.11) | 402 | 1.06 (0.95, 1.19) | 1.02 (0.91, 1.14) |
|
Late preterm (34–36 weeks) |
11,822 | Ref | Ref | 1900 | 2.07 (1.96, 2.18) | 1.91 (1.81, 2.03) | 100 | 0.60 (0.49, 0.74) | 0.60 (0.50, 0.74) | 958 | 1.11 (1.04, 1.19) | 1.14 (1.07, 1.23) | 865 | 1.00 (0.94, 1.08) | 1.01 (0.94, 1.09) | 2659 | 0.93 (0.89, 0.97) | 0.89 (0.85, 0.93) |
|
Early term (37–38 weeks) |
73,135 | Ref | Ref | 6173 | 1.09 (1.05, 1.12) | 1.20 (1.17, 1.25) | 656 | 0.64 (0.58, 0.70) | 0.62 (0.57, 0.68) | 6196 | 1.16 (1.12, 1.20) | 1.15 (1.11, 1.19) | 5903 | 1.11 (1.07, 1.15) | 1.06 (1.02, 1.09) | 17,311 | 0.98 (0.96, 1.00) | 0.90 (0.88, 0.92) |
|
Full term (39–41 weeks) |
142,379 | 11,054 | 2004 | 10,386 | 10,360 | 34,345 | ||||||||||||
|
Post term (42 > weeks) |
318 | Ref | Ref | 41 | 1.67 (1.20, 2.30) | 1.73 (1.20, 2.48) | 9 | 2.01 (1.03, 3.90) | 1.93 (0.99, 3.78) | 23 | 0.99 (0.65, 1.51) | 0.98 (0.64, 1.50) | 18 | 0.78 (0.48, 1.25) | 0.76 (0.47, 1.22) | 59 | 0.77 (0.58, 1.01) | 0.73 (0.55, 0.97) |
ANI Australian-born mothers of non-Indigenous backgrounds, AI Australian-born mothers of Indigenous background, FB-LIC foreign-born mothers from low-income countries, FB-LMIC foreign-born mothers from lower-middle-income countries, FB-UMIC foreign-born mothers of upper-middle-income countries, FB-HIC foreign-born mothers from high-income countries, cRRR crude relative risk ratio, aRRR adjusted relative risk ratio, CI confidence interval, Ref reference group
a Adjusted for parity, birth year, SEIFA score, maternal smoking status, maternal age, and sex