1st year | 2nd–5th years | 6th–10th years | 11th–20th years | After 20th year | Unknown | P values* | |||||||
n=19 948 | n=60 894 | n=66 474 | n=96 855 | n=75 314 | n=25 425 | ||||||||
n | % | n | % | n | % | n | % | n | % | n | % | ||
Ethnicity† | |||||||||||||
Māori | 6151 | 30.84 | 17 737 | 29.13 | 18 352 | 27.61 | 26 310 | 27.16 | 16 306 | 21.65 | 6265 | 24.64 | |
Pacific | 2120 | 10.63 | 4758 | 7.81 | 5633 | 8.47 | 10 234 | 10.57 | 5663 | 7.52 | 2163 | 8.51 | |
Indian | 682 | 3.42 | 1595 | 2.62 | 1756 | 2.64 | 3129 | 3.23 | 2438 | 3.24 | 773 | 3.04 | |
Other Asian | 1918 | 9.61 | 5309 | 8.72 | 5970 | 8.98 | 7370 | 7.61 | 5302 | 7.04 | 1581 | 6.22 | |
MELAA | 388 | 1.95 | 1083 | 1.78 | 1055 | 1.59 | 1691 | 1.75 | 1491 | 1.98 | 460 | 1.81 | |
European | 8689 | 43.56 | 30 406 | 49.93 | 33 702 | 50.70 | 48 114 | 49.68 | 44 105 | 58.56 | 14 181 | 55.78 | <0.001 |
Unknown | 0 | 0.00 | 6 | 0.01 | 6 | 0.01 | 7 | 0.01 | 9 | 0.01 | 2 | 0.01 | |
Age† | |||||||||||||
<20 | 2171 | 10.88 | 5132 | 8.43 | 4533 | 6.82 | 5815 | 6.00 | 3641 | 4.83 | 1557 | 6.12 | |
20–24 | 4877 | 24.45 | 13 741 | 22.57 | 13 349 | 20.08 | 17 366 | 17.93 | 11 007 | 14.61 | 4624 | 18.19 | |
25–34 | 9991 | 50.09 | 32 339 | 53.11 | 36 343 | 54.67 | 53 774 | 55.52 | 41 924 | 55.67 | 13 855 | 54.49 | |
35–39 | 2426 | 12.16 | 8000 | 13.14 | 10 173 | 15.30 | 16 367 | 16.90 | 15 441 | 20.50 | 4504 | 17.71 | |
≥40 | 483 | 2.42 | 1682 | 2.76 | 2076 | 3.12 | 3533 | 3.65 | 3301 | 4.38 | 885 | 3.48 | <0.001 |
Deprivation quintile† | |||||||||||||
1 | 2333 | 11.70 | 7754 | 12.73 | 9016 | 13.56 | 13 291 | 13.72 | 12 094 | 16.06 | 3332 | 13.11 | |
2 | 2606 | 13.06 | 9585 | 15.74 | 10 072 | 15.15 | 14 003 | 14.46 | 12 505 | 16.60 | 4532 | 17.82 | |
3 | 3654 | 18.32 | 11 929 | 19.59 | 12 951 | 19.48 | 17 385 | 17.95 | 15 444 | 20.51 | 5390 | 21.20 | |
4 | 5325 | 26.69 | 15 714 | 25.81 | 16 281 | 24.49 | 23 628 | 24.40 | 17 908 | 23.78 | 5561 | 21.87 | |
5 | 5931 | 29.73 | 15 609 | 25.63 | 17 849 | 26.85 | 28 073 | 28.98 | 17 003 | 22.58 | 6514 | 25.62 | <0.001 |
Unknown | 99 | 0.50 | 303 | 0.50 | 305 | 0.46 | 475 | 0.49 | 360 | 0.48 | 96 | 0.38 | |
Parity† | |||||||||||||
0 | 10 311 | 51.69 | 26 952 | 44.26 | 25 833 | 38.86 | 36 488 | 37.67 | 28 277 | 37.55 | 10 155 | 39.94 | |
1–2 | 7571 | 37.95 | 27 751 | 45.57 | 33 077 | 49.76 | 48 103 | 49.66 | 38 681 | 51.36 | 12 510 | 49.20 | |
3 | 1045 | 5.24 | 3331 | 5.47 | 4148 | 6.24 | 6481 | 6.69 | 4675 | 6.21 | 1569 | 6.17 | |
≥4 | 1017 | 5.10 | 2855 | 4.69 | 3414 | 5.14 | 5775 | 5.96 | 3676 | 4.88 | 1187 | 4.67 | <0.001 |
Unknown | 4 | 0.02 | 5 | 0.01 | 2 | 0.00 | 8 | 0.01 | 5 | 0.01 | 4 | 0.02 | |
Smoking at booking† | |||||||||||||
Yes | 4419 | 22.15 | 11 829 | 19.43 | 11 423 | 17.18 | 15 164 | 15.66 | 9719 | 12.90 | 3902 | 15.35 | |
No | 15 523 | 77.82 | 49 052 | 80.55 | 55 043 | 82.80 | 81 676 | 84.33 | 65 587 | 87.08 | 21 513 | 84.61 | <0.001 |
Missing | 6 | 0.03 | 13 | 0.02 | 8 | 0.01 | 15 | 0.02 | 8 | 0.01 | 10 | 0.04 | |
BMI† | |||||||||||||
<18.5 | 640 | 3.21 | 1862 | 3.06 | 1945 | 2.93 | 2507 | 2.59 | 1954 | 2.59 | 653 | 2.57 | |
18.5–24.99 | 9648 | 48.37 | 29 987 | 49.24 | 33 136 | 49.85 | 46 767 | 48.29 | 39 042 | 51.84 | 12 798 | 50.34 | |
25–29.99 | 5072 | 25.43 | 15 776 | 25.91 | 17 336 | 26.08 | 25 247 | 26.07 | 19 461 | 25.84 | 6525 | 25.66 | |
30–34.99 | 2701 | 13.54 | 8009 | 13.15 | 8301 | 12.49 | 13 109 | 13.53 | 9008 | 11.96 | 3170 | 12.47 | |
35–39.99 | 1182 | 5.93 | 3308 | 5.43 | 3623 | 5.45 | 5798 | 5.99 | 3638 | 4.83 | 1432 | 5.63 | |
≥40 | 660 | 3.31 | 1828 | 3.00 | 1979 | 2.98 | 3185 | 3.29 | 2038 | 2.71 | 784 | 3.08 | <0.001 |
Missing or <15 or >100 | 45 | 0.23 | 124 | 0.20 | 154 | 0.23 | 242 | 0.25 | 173 | 0.23 | 63 | 0.25 |
*Excludes unknown; χ2 test.
↵†Data from MAT.
BMI, body mass index; MAT, National Maternity Collection; MELAA, Middle-Eastern, Latin American or African.