Incidence of Blood Transfusion for Cesarean Delivery
The overall incidence of blood transfusion during cesarean delivery ranges from 2-4% in routine cases, but increases dramatically to 12-25% in high-risk populations, particularly those with placenta previa, placenta accreta spectrum, or severe anemia.
Overall Transfusion Rates
The incidence varies significantly based on patient risk factors and clinical setting:
- Routine cesarean delivery: 2.2-3.8% 1, 2
- Primary cesarean: 3.2% 1
- Repeat cesarean: 2.2% 1
- High-risk tertiary centers: 12.2-25.2% 3, 4
- Emergency cesarean: 3.84% (higher than elective at 1.58%) 5
A contemporary 2026 multicenter study of over 10,000 cesarean deliveries found that among patients with estimated blood loss >1 liter, 21.1% received packed red blood cells 2. However, when examining all cesarean deliveries regardless of blood loss, the transfusion rate was 3.8% 6.
High-Risk Conditions with Dramatically Elevated Transfusion Risk
Placenta previa represents the highest risk, with blood transfusion being approximately 12 times more likely compared to cesarean delivery for other indications 7. Women with placenta previa have:
- 19% hemorrhagic morbidity rate (versus 7% in controls, adjusted RR 2.6) 7
- Risk of blood loss >1000 ml increased 4-fold (RR 3.97,95% CI 3.24-4.85) 7
Placenta accreta spectrum increases transfusion likelihood 6-fold (aOR 6.530,95% CI 4.056-10.510) 8.
Severe preoperative anemia (hematocrit <25%) increases transfusion odds 17-19 times:
Uterine atony increases transfusion risk 3.5-fold (aOR 3.612,95% CI 2.599-5.019) 8.
Additional Risk Factors
Other factors significantly associated with increased transfusion risk include 3, 1, 6:
- Abruptio placentae: OR 4.18 (95% CI 2.02-8.62)
- General anesthesia: OR 2.48-7.2 (higher in repeat cesarean)
- Five or more prior cesareans: OR 7.6 (95% CI 4.0-14.3)
- Intraoperative complications (uterine incision extension, hysterectomy): OR 2.69
- Cesarean during second stage of labor
- Gestational age <34 weeks or ≥41 weeks
- Chorioamnionitis
- Aspirin use within 7 days of delivery
- Preoperative platelet count <100,000
Temporal Trends
Historical data shows a declining trend in transfusion rates over time. One study documented a decrease from 6.2% to 3.2% between 1984-1987 9, though more recent data from 2026 shows rates have stabilized around 3-4% for routine cases 2, 6.
Clinical Implications
For routine, low-risk cesarean deliveries, the transfusion incidence of 2-4% suggests that universal crossmatching may not be necessary. However, for high-risk cases (placenta previa, accreta spectrum, severe anemia, multiple prior cesareans), the dramatically elevated rates of 12-25% mandate:
- Delivery at facilities with on-site blood transfusion services 7
- Preoperative crossmatching and blood availability 7
- Senior surgical and anesthesia teams present 7
- Consideration of cell salvage equipment 7
The median transfusion volume when transfusion occurs is typically 2 units (25th-75th percentile: 2-3 units for primary cesarean, 2-4 units for repeat cesarean) 1.