Previous PPH is the Most Significant Risk Factor
In a woman with a history of previous postpartum hemorrhage, that prior PPH itself represents the single most significant risk factor for recurrent hemorrhage, conferring a 3.5 to 4-fold increased risk compared to unaffected women. 1
Understanding the Hierarchy of Risk Factors
While all the listed options represent recognized risk factors for PPH, the evidence clearly stratifies their relative importance:
Previous PPH: The Dominant Risk Factor
- Women with previous PPH have a 19.1% recurrence rate compared to only 5.4% in unaffected women (OR 4.1; 95% CI 3.7-4.5). 1
- Previous PPH is identified as an independent risk factor in multivariate analysis, maintaining significance even when controlling for other variables. 2
- The risk is particularly elevated when the previous PPH involved blood transfusion or manual removal of placenta. 1
- Previous PPH is explicitly listed among the most significantly associated factors with hemorrhage. 3
Other Risk Factors in Context
Multiparity shows weaker association than commonly assumed:
- Multiparity itself is only a weakly associated factor according to systematic analysis. 3
- Grand multiparity (≥5 deliveries) does appear in 51.5% of PPH cases, but this reflects population demographics rather than independent causation. 4
Multiple gestation carries moderate risk:
- Multiple pregnancy is recognized as a risk factor but appears in only 1.5-2.1% of PPH cases. 4, 3
- It contributes to uterine overdistension and atony but is less predictive than previous PPH. 5
Macrosomic baby (>4000g birth weight):
- Birth weight exceeding 4000g is significantly associated with PPH. 3
- However, it does not approach the predictive power of previous PPH history. 1, 2
Clinical Implications for This Patient
For a G3P2 patient with previous PPH:
- The recurrence risk is approximately 19%, nearly 4 times higher than baseline. 1
- This risk supersedes concerns about multiparity, singleton versus multiple gestation, or fetal size. 1, 2
- Active management of third stage with oxytocin should be implemented. 6
- Tranexamic acid 1g IV should be immediately available and administered within 3 hours if bleeding occurs, as effectiveness declines 10% for every 15 minutes of delay. 7
- Blood type and screen should be performed before delivery. 6
Common Pitfalls to Avoid
- Do not assume multiparity alone confers high risk - it is only weakly associated when previous PPH is absent. 3
- Do not underestimate the power of previous PPH history - it remains the strongest predictor even in multivariate models. 2
- The etiology of the previous PPH matters: if it was due to a specific non-recurrent condition (like molar pregnancy), the risk profile changes. 6
- However, in typical cases of previous PPH from atony or trauma, the recurrence risk remains substantially elevated. 1