Table 1.
Characteristics of PTL/PTB Mothers Compared with Non-PTL/PTB Mothers at Delivery
| PTL/PTB mothers | Non-PTL/PTB mothers | P –valuea | |
|---|---|---|---|
| N = 2147 | N = 8778 | ||
| N (%) | N (%) | ||
| Year of delivery | 0.3403 | ||
| 2009 | 395 (18.4) | 1645 (18.7) | |
| 2010 | 420 (19.6) | 1726 (19.7) | |
| 2011 | 413 (19.2) | 1819 (20.7) | |
| 2012 | 472 (22.0) | 1778 (20.3) | |
| 2013 | 447 (20.8) | 1810 (20.6) | |
| Maternal age at deliveryb | < 0.0001 | ||
| 12–18 years | 48 (2.2) | 95 (1.1) | |
| 19–30 years | 1276 (59.4) | 5194 (59.2) | |
| 31–35 years | 496 (23.1) | 2232 (25.4) | |
| 36–44 years | 327 (15.2) | 1257 (14.3) | |
| Nulliparousc | 1360 (63.3) | 5224 (59.5) | 0.0011 |
| Caesarean section | 885 (41.2) | 2769 (31.5) | < 0.0001 |
| Birth plurality | < 0.0001 | ||
| Singleton | 1969 (91.7) | 8709 (99.2) | |
| Twin | 173 (8.1) | 64 (0.0) | |
| Other multiple | 5 (0.0) | 3 (0.0) | |
| Charlson Comorbidity Indexd | 0.0142 | ||
| 0 | 1750 (81.5) | 7332 (83.5) | |
| 1 | 315 (14.7) | 1155 (13.2) | |
| 2 | 54 (2.5) | 230 (2.6) | |
| 3 | 21 (1.0) | 41 (0.5) | |
| 4+ | 7 (0.3) | 20 (0.2) | |
| Selected comorbiditiesd | |||
| Gestational diabetes | 237 (11.0) | 893 (10.2) | 0.2378 |
| Hypertension | 93 (4.3) | 243 (2.8) | 0.0002 |
| Depression | 83 (3.9) | 334 (3.8) | 0.8950 |
| Hypotension | 66 (3.1) | 268 (3.1) | 0.9597 |
| Diabetes mellitus | 50 (2.3) | 113 (1.3) | 0.0004 |
aP-values compare PTL/PTB mothers with non-PTL/PTB mothers, and are calculated using the chi-squared test/Fisher’s Exact test in instances when expected cell counts < 5
bValues are rounded to the nearest whole number
cRefers to parity preceding index delivery
dMeasured during the nine-month baseline period, diagnoses in inpatient or outpatient setting
Abbreviations: PTB preterm birth, PTL preterm labour