Risk factor prevalence | |||
---|---|---|---|
Risk factor | 2001 N=84 302 n (%) | 2012 N=96 051 n (%) | Trend over time p Value |
Established risk factors for pregnancy hypertension | |||
Nulliparity | 35 134 (41.7) | 42 189 (43.9) | <0.0001 |
Maternal age ≥35 years | 15 222 (18.1) | 22 556 (23.5) | <0.0001 |
Maternal age <20 years | 3797 (4.5) | 3158 (3.3) | <0.0001 |
Diabetes (any) | 4000 (4.7) | 8812 (9.2) | <0.0001 |
Morbid obesity | 125 (0.2) | 809 (0.8) | <0.0001 |
NSW overweight/obesity rate | 28.4% | 33.2% | |
Overweight | 17.6% | 19.7% | Not reported |
Obese | 10.8% | 13.5% | |
ART | 1323 (1.6) | 2971 (3.1) | <0.0001 |
Smoking | 15 629 (18.5) | 11 046 (11.5) | <0.0001 |
Multiple births | 1452 (1.7) | 1316 (1.4) | <0.0001 |
Autoimmune diseases | 387 (0.5) | 404 (0.4) | <0.0001 |
Previous pregnancy hypertension* | 3932 (8.0)† | 3929 (7.3) | <0.0001 |
Asian ethnicity | 7924 (9.4) | 17 647 (18.4) | <0.0001 |
Chronic hypertension | 548 (0.7) | 622 (0.7) | 0.12 |
Renal disease | 186 (0.2) | 278 (0.3) | 0.24 |
Interpregnancy interval ≥5 years* | 7156 (15.9)† | 7461 (15.6) | 0.62 |
Summer birth | 20 143 (23.9) | 23 193 (24.2) | 0.27 |
Obstetric factors | |||
Gestational age, weeks | |||
<37 | 5457 (6.5) | 6649 (6.9) | <0.0001 |
37 | 4215 (5.0) | 6544 (6.8) | <0.0001 |
38 | 12 491 (14.8) | 17 654 (18.4) | <0.0001 |
39 | 18 993 (22.5) | 28 395 (29.6) | <0.0001 |
40 | 26 780 (31.8) | 24 183 (25.2) | <0.0001 |
≥41 | 16 354 (19.4) | 12 622 (13.1) | <0.0001 |
Planned deliveries (any) | 31 823 (37.8) | 43 846 (45.7) | <0.0001 |
Prelabour CS | 10 910 (12.9) | 17 705 (18.4) | <0.0001 |
Labour inductions | 20 913 (24.8) | 26 141 (27.2) | <0.0001 |
Any planned delivery at 37–39 weeks | 15 007 (17.8) | 26 058 (27.1) | <0.0001 |
Sociodemographic factors | |||
Socioeconomic status | |||
Lowest (quintile) | 16 903 (20.1) | 18 911 (19.7) | 0.15 |
Middle (quintiles 2–4) | 51 277 (60.8) | 57 231 (59.6) | <0.0001 |
Highest (quintile) | 16 007 (19.0) | 19 126 (19.9) | <0.0001 |
Maternal residence (urban vs rural) | 57 537 (68.3) | 68 290 (71.5) | <0.0001 |
Maternity hospital type | |||
Tertiary obstetric | 36 415 (43.2) | 47 020 (49.0) | <0.0001 |
Urban district | 19 333 (22.9) | 18 824 (19.6) | <0.0001 |
Rural district | 9237 (11.0) | 8412 ( 8.8) | <0.0001 |
Private | 19 317 (22.9) | 21 795 (22.7) | <0.0001 |
Per cents may not add to 100% because of missing data: 1579 (0.01%) parity, 298 (0.03%), 520 (0.05%) smoking, 4232 (0.39%) country of birth, 45 765 (4.3%) interpregnancy interval, 159 (0.01%) gestational age, 178 (0.02%) planned births, 4163 (0.39%) socioeconomic status, 2740 (0.25%) maternal residence and 20 (0.001%) hospital type.
*Among multipara.
†Reported rate is for 2003 (prior pregnancy hypertension) and 2006 (interpregnancy interval) to allow a sufficient lookback period for previous pregnancies.
ART, assisted reproductive technology; CS, caesarean section; NSW, New South Wales.