Table 4. Factors associated with increased risk of postpartum haemorrhage in a second birth, amongst women with a first and second birth.
| Postpartum Haemorrhage | aRRe | 95% Confidence Interval | P value | ||
|---|---|---|---|---|---|
| Private Insurance | Yes | 4271/ 87759 (4.9) | 0.6 | (0.6, 0.6) | < .0001 |
| No | 12034/ 139488 (8.6) | Reff | |||
| Australian born | Yes | 11174/ 162402 (6.9) | 0.9 | (0.9, 0.9) | < .0001 |
| No | 5131/ 64845 (7.9) | Ref | |||
| Smoker | Yes | 1623/ 21348 (7.6) | 1.0 | (0.9, 1.0) | 0.2 |
| No | 14638/ 205290 (7.1) | Ref | |||
| Any ARTa | Yes | 559/ 8205 (6.8) | 1.2 | (1.1, 1.3) | <0.01 |
| No | 15746/ 219042 (7.2) | Ref | |||
| Pregnancy hypertension | Yes | 1797/ 24472 (7.3) | 1.0 | (1.0, 1.0) | 0.9 |
| No | 14508/ 202775 (7.2) | Ref | |||
| Chronic hypertension | Yes | 117/ 1674 (7.0) | 0.9 | (0.8, 1.1) | 0.5 |
| No | 16188/ 225573 (7.2) | Ref | |||
| Gestational diabetes | Yes | 845/ 11646 (7.3) | 0.9 | (0.9, 1.0) | 0.1 |
| No | 15460/ 215601 (7.2) | Ref | |||
| Chronic conditions | Yes | 446/ 5610 (8.0) | 1.1 | (1.0, 1.2) | 0.1 |
| No | 15859/ 221637 (7.2) | Ref | |||
| Large for gestational age | Yes | 1609/ 17495 (9.2) | 1.2 | (1.2, 1.3) | < .0001 |
| No | 14696/ 209752 (7.0) | Ref | |||
| Morbidly adherent placenta | Yes | 83/ 428 (19.4) | 1.7 | (1.4, 2.1) | < .0001 |
| No | 16222/ 226819 (7.2) | Ref | |||
| Placenta praevia | Yes | 101/ 1644 (6.1) | 0.9 | (0.7, 1.1) | 0.2 |
| No | 16204/ 225603 (7.2) | Ref | |||
| Maternal age | Under 20 | 1470/ 16631 (8.8) | 1.1 | (1.1, 1.2) | <0.01 |
| 20–34 | 13421/ 188582 (7.1) | Ref | |||
| 35+ | 1413/ 21999 (6.4) | 1.0 | (0.9, 1.1) | ||
| Socioeconomic status | Highest disadvantage | 3431/ 44950 (7.6) | 1.1 | (1.0, 1.1) | < .0001 |
| 2 | 3272/ 42651 (7.7) | 1.1 | (1.1, 1.2) | ||
| 3 | 3287/ 42426 (7.7) | 1.2 | (1.1, 1.2) | ||
| 4 | 3170/ 44902 (7.1) | 1.1 | (1.0, 1.2) | ||
| Highest SESc | 2955/ 50191 (5.9) | Ref | |||
| PPHb Type* | +PPH+RBCd | 513/ 2399 (21.4) | 3.0 | (2.8, 3.3) | < .0001 |
| +PPH -RBC | 2806/ 16869 (16.6) | 2.4 | (2.4, 2.5) | ||
| -PPH+RBC | 58/ 491 (11.8) | 1.7 | (1.3, 2.2) | ||
| -PPH-RBC | 12928/ 207488 (6.2) | Ref | |||
| Year of birth | 1 | (1.0, 1.0) | < .0001 |
aART: Assisted reproductive technology;
bPPH: Postpartum haemorrhage;
cSES: socioeconomic status;
dRBC, Red blood cell;
eaRR: Adjusted Relative Risk.
fRef: reference category
* +RBC +PPH: Transfusion and haemorrhage; +RBC-PPH: Transfusion without haemorrhage; -RBC +PPH: Haemorrhage without transfusion;-RBC–PPH: neither haemorrhage nor transfusion.