Table 2.
Risk of pre/post term relative to full term by maternal country of birth: 1980 to 1996 (n = 385,180)
| Gestational age | ANI (n = 253,716) |
AI (n = 20,360) |
FB-LIC (n = 1265) |
FB-LMIC (n = 13,890) |
FB-UMIC (n = 12,469) |
FB-HIC (n = 83,480) |
||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 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) |
1403 | Ref | Ref | 301 | 3.37 (2.97, 3.81) | 3.20 (2.78, 3.68) | 11 | 1.63 (0.90, 2.96) | 1.59 (0.87, 2.89) | 76 | 1.12 (0.89, 1.41) | 1.04 (0.82, 1.31) | 68 | 1.04 (0.82, 1.33) | 0.98 (0.77, 1.25) | 453 | 0.99 (0.89, 1.11) | 0.96 (0.86, 1.07) |
|
Very early preterm (28–32 weeks) |
1561 | Ref | Ref | 313 | 3.15 (2.78, 3.56) | 2.67 (2.33, 3.06) | 12 | 1.60 (0.90, 2.83) | 1.63 (0.92, 2.89) | 86 | 1.14 (0.92, 2.83) | 1.11 (0.89, 1.38) | 74 | 1.02 (0.81, 1.29) | 1.01 (0.80, 1.27)) | 554 | 1.09 (0.89, 1.11) | 1.09 (0.99, 1.20) |
|
Early preterm (32–33 weeks) |
1891 | Ref | Ref | 323 | 2.68 (2.38, 3.02) | 2.52 (2.21, 2.88) | 9 | 0.99 (0.51, 1.91) | 0.98 (0.51, 1.89) | 104 | 1.14 (0.92, 1.42) | 1.09 (0.89, 1.33) | 98 | 1.12 (0.92, 1.37) | 1.08 (0.88, 1.33) | 677 | 1.10 (1.01, 1.20) | 1.08 (0.99, 1.18) |
|
Late preterm (34–36 weeks) |
11,263 | Ref | Ref | 2136 | 2.98 (2.83, 3.13) | 2.80 (2.65, 2.95) | 55 | 1.02 (0.77, 1.34) | 1.00 (0.77, 1.33) | 761 | 1.40 (1.30, 1.51) | 1.35 (1.25, 1.46) | 608 | 1.16 (1.07, 1.27) | 1.13 (1.04, 1.23) | 3970 | 1.09 (1.05, 1.13) | 1.07 (1.03, 1.11) |
|
Early term (37–38 weeks) |
58,132 | Ref | Ref | 5727 | 1.55 (1.50, 1.60) | 1.61 (1.55, 1.67) | 316 | 1.13 (0.99, 1.29) | 1.08 (0.95, 1.23) | 4196 | 1.50 (1.44, 1.55) | 1.42 (1.37, 1.48) | 3296 | 1.22 (1.17, 1.27) | 1.16 (1.11, 1.21) | 19,597 | 1.04 (1.02, 1.06) | 1.01 (0.99, 1.03) |
|
Full term (39–41 weeks) |
178,157 | 11,353 | 856 | 8594 | 8265 | 57,817 | ||||||||||||
|
Post term (42 > weeks) |
1309 | Ref | Ref | 207 | 2.48 (2.14, 2.88) | 1.58 (1.34, 1.85) | 6 | 0.95 (0.43, 2.13) | 1.11 (0.49, 2.47) | 73 | 1.16 (0.91, 1.46) | 1.29 (1.01, 1.64) | 60 | 0.99 (0.76, 1.28) | 1.12 (0.86, 1.45) | 412 | 0.97 (0.87, 1.08) | 1.05 (0.94, 1.17) |
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 age, and sex