Table 2 Crude and adjusted odds ratios with confidence intervals (95%CI) for PTB and LBW births by maternal migrant status

PTB, n (%)

39,986 (5.79)

147,697 (5.29)

85,860 (4.95)

 OR (95%CI)

1.00

0.908 (0.898, 0.918)

0.846 (0.836, 0.856)

< 0.001 ^{A, B, C}

 OR _adj (95%CI)

1.00

0.944 (0.933, 0.955)

0.869 (0.858, 0.879)

< 0.001 ^{A, B, C}

< 28w, n (%)

523 (0.08)

1542 (0.06)

975 (0.06)

 OR (95%CI)

1.00

0.725 (0.656, 0.800)

0.734 (0.660, 0.817)

< 0.001 ^{A, B, C}

 OR _adj (95%CI)

1.00

0.755 (0.684, 0.834)

0.793 (0.713, 0.882)

0.006 ^{A, B, C}

28 ∽ 31w, n (%)

3264 (0.47)

11,248 (0.40)

7837 (0.45)

 OR (95%CI)

1.00

0.847 (0.814, 0.881)

0.946 (0.908, 0.985)

< 0.001 ^{A, B, C}

 OR _adj (95%CI)

1.00

0.889 (0.855, 0.924)

0.982 (0.942, 1.023)

< 0.001 ^{A, B, C}

32 ∽ 36w, n (%)

36,199 (5.24)

134,907 (4.83)

77,048 (4.44)

 OR (95%CI)

1.00

0.916 (0.905, 0.927)

0.839 (0.828, 0.849)

< 0.001 ^{A, B, C}

 OR _adj (95%CI)

1.00

0.952 (0.940, 0.963)

0.860 (0.849, 0.871)

< 0.001 ^{A, B, C}

LBW, n%

34,384 (4.98)

137,262 (4.91)

69,473 (4.00)

 OR (95%CI)

1.00

0.986 (0.974, 0.998)

0.795 (0.785, 0.806)

< 0.001 ^{A, B, C}

 OR _adj (95%CI)

1.00

1.001 (0.989, 1.014)

0.792 (0.781, 0.802)

< 0.001 ^{A, B, C}

500 ∽ 999 g, n%

641 (0.09)

1584 (0.05)

1044 (0.06)

 OR (95%CI)

1.00

0.610 (0.557, 0.669)

0.641 (0.581, 0.707)

< 0.001 ^{A, B, C}

 OR _adj (95%CI)

1.00

0.665 (0.607, 0.729)

0.698 (0.632, 0.770)

< 0.001 ^{A, B, C}

1000 ∽ 1499 g, n%

2336 (0.34)

8560 (0.31)

5311 (0.31)

 OR (95%CI)

1.00

0.905 (0.864, 0.947)

0.895 (0.852, 0.939)

< 0.001 ^{A, B, C}

 OR _adj (95%CI)

1.00

0.964 (0.921, 1.009)

0.930 (0.885, 0.976)

< 0.001 ^{A, B, C}

1500 ∽ 2499 g, n%

31,407 (4.55)

127,118 (4.55)

63,118 (3.63)

 OR (95%CI)

1.00

0.999 (0.987, 1.012)

0.791 (0.780, 0.802)

< 0.001 ^{A, B, C}

 OR _adj (95%CI)

1.00

1.011 (0.998, 1.023)

0.784 (0.773, 0.795)

< 0.001 ^{A, B, C}