Table 1.
Preterm births in singleton and multiple pregnancies and in primiparous and multiparous women in China, 2012–18
|
Year |
Change 2012–18 | Annual rate of increase (95% CI)*†‡ | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Total | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | |||
| All pregnancies (n=9 645 646) | ||||||||||
| Very preterm | 73 681 (0·6%) | 9079 (0·6%) | 9461 (0·6%) | 10 755 (0·6%) | 9949 (0·7%) | 11 569 (0·7%) | 11 784 (0·6%) | 11 084 (0·7%) | 13·3% | 1·8% (0·5 to 3·0) |
| Moderate preterm | 92 551 (0·8%) | 12 241 (0·8%) | 12 326 (0·8%) | 13 655 (0·8%) | 12 377 (0·8%) | 14 068 (0·8%) | 14 317 (0.8%) | 13 567 (0·8%) | 3·8% | 0·3% (−0·9 to 1·5) |
| Late preterm | 499 012 (4·7%) | 65 047 (4·5%) | 63 832 (4·5%) | 72 604 (4·5%) | 66 294 (4·6%) | 77 565 (4·7%) | 79 706 (4·8%) | 73 964 (4·9%) | 8·8% | 1·5% (0·9 to 2·2) |
| All preterm | 665 244 (6·1%) | 86 367 (5·9%) | 85 619 (5·9%) | 97 014 (5·9%) | 88 620 (6·1%) | 10 3202 (6·2%) | 10 5807 (6·2%) | 98 615 (6·4%) | 8·8% | 1·3% (0·6 to 2·1) |
| Singleton pregnancies (n=9 474 961)§ | ||||||||||
| Very preterm | 64 058 (0·6%) | 7948 (0·5%) | 8288 (0.6%) | 9270 (0·6%) | 8589 (0·6%) | 10 092 (0·6%) | 10 254 (0·6%) | 9617 (0·6%) | 13·2% | 1·6% (0·4 to 2·9) |
| Moderate preterm | 78 953 (0·7%) | 10 524 (0·7%) | 10 579 (0·7%) | 11 615 (0·7%) | 10 535 (0·7%) | 12 017 (0·7%) | 12 232 (0·7%) | 11 451 (0·7%) | 2·9% | 0 (−1·2 to 1·3) |
| Late preterm | 432 751 (4·1%) | 57 284 (4·1%) | 55 688 (4·0%) | 62 973 (4·0%) | 57 342 (4·1%) | 67 692 (4·2%) | 68 769 (4·2%) | 63 003 (4·3%) | 6·1% | 1·2% (0·5 to 1·8) |
| All preterm | 575 762 (5·4%) | 75 756 (5·3%) | 74 555 (5·3%) | 83 858 (5·3%) | 76 466 (5·4%) | 89 801 (5·5%) | 91 255 (5·5%) | 84 071 (5·7%) | 6·4% | 1·0% (0·4 to 1·7) |
| Multiple pregnancies (n=170 547)§ | ||||||||||
| Very preterm | 9606 (5·1%) | 1127 (4·8%) | 1164 (4·9%) | 1484 (5·3%) | 1360 (5·2%) | 1476 (5·2%) | 1529 (5·1%) | 1466 (5·1%) | 6·0% | 2·5% (1·0 to 4·0) |
| Moderate preterm | 13 588 (7·2%) | 1710 (7·2%) | 1747 (7·2%) | 2038 (7·3%) | 1841 (7·1%) | 2051 (7·4%) | 2085 (7·1%) | 2116 (7·4%) | 3·1% | 1·8% (0·3 to 3·4) |
| Late preterm | 66 245 (37·1%) | 7762 (34·8%) | 8141 (35·5%) | 9629 (36·2%) | 8951 (36·3%) | 9872 (37·2%) | 10 933 (38·9%) | 10 957 (40·1%) | 15·2% | 2·4% (1·6 to 3·2) |
| All preterm | 89 439 (49·4%) | 10 599 (46·8%) | 11052 (47·5%) | 13 151 (48·8%) | 12 152 (48·5%) | 13 399 (49·8%) | 14 547 (51·1%) | 14 539 (52·7%) | 12·4% | 1·9% (1·2 to 2·6) |
| Primiparous women (n=5 440 535)¶ | ||||||||||
| Very preterm | 37 851 (0·6%) | 5295 (0·5%) | 5481 (0·6%) | 5891 (0·6%) | 5243 (0·6%) | 5728 (0·6%) | 5293 (0·6%) | 4920 (0·6%) | 18·5% | 2·9% (1·2 to 4·7) |
| Moderate preterm | 48 866 (0·8%) | 7476 (0·8%) | 7314 (0·8%) | 7770 (0·8%) | 6607 (0·8%) | 7117 (0·8%) | 6529 (0·8%) | 6053 (0·8%) | 5·3% | 0·7% (−1·3 to 2·8) |
| Late preterm | 270 558 (4·5%) | 41 472 (4·4%) | 39 194 (4·4%) | 42 709 (4·4%) | 36 321 (4.6%) | 40 023 (4·6%) | 36 609 (4·7%) | 34 230 (4·8%) | 9·1% | 1·7% (0·9 to 2·4) |
| All preterm | 357 275 (5·9%) | 54 243 (5·7%) | 51 989 (5·7%) | 56 370 (5·7%) | 48 171 (6.0%) | 52 868 (6·0%) | 48 431 (6·1%) | 45 203 (6·2%) | 9·3% | 1·6% (0·7 to 2·6) |
| Multiparous women (n=4 194 100)¶ | ||||||||||
| Very preterm | 35 145 (0·7%) | 3774 (0·7%) | 3973 (0·7%) | 4855 (0·7%) | 4699 (0.7%) | 5837 (0·7%) | 6298 (0·6%) | 5709 (0·7%) | −5·7% | −1·6% (−3·1 to −0·1) |
| Moderate preterm | 430 86 (0·8%) | 4755 (0·9%) | 5005 (0·9%) | 5877 (0·9%) | 5766 (0·8%) | 6943 (0·8%) | 7629 (0.8%) | 7111 (0·8%) | −5·7% | −1·7% (−3·1 to −0·2) |
| Late preterm | 226 805 (4·8%) | 23 515 (4·7%) | 24 618 (4·7%) | 29 868 (4·7%) | 29 955 (4·7%) | 37 523 (4·8%) | 42 648 (4·8%) | 38 678 (4·9%) | 4·4% | 0·6% (−0·2 to 1·5) |
| All preterm | 305 036 (6·3%) | 32 044 (6·3%) | 33 596 (6·3%) | 40 600 (6·3%) | 40 420 (6·3%) | 50 303 (6·3%) | 56 575 (6·2%) | 51 498 (6·4%) | 1·9% | 0·1% (−0·8 to 1·0) |
Data are n (%), unless otherwise stated. % represents the number of liveborn preterm deliveries per 100 deliveries, adjusting for the sampling distribution of the population. Annual rate of increase represents the annual rate change in preterm birth rate from 2012 to 2018. Very preterm babies were born after 28–31 completed weeks' gestation. Moderate preterm babies were born after 32–33 weeks' gestation. Late preterm babies were born after 34–36 weeks' gestation.
Estimated by Poisson regression model with robust standard error.
Adjusted for the sampling distribution of the population.
Adjusted for the clustering of births within hospitals.
The records of 138 (<0·1%) pregnancies did not contain information regarding the number of fetuses.
A total of 11 011 (0·1%) women did not report information on parity.