What are the rates of complications associated with cesarean delivery?

Cesarean delivery is one of the most common major surgeries performed worldwide. As primary, repeat, and elective cesarean rates continue to increase, so do rates of hemorrhage, placenta accreta spectrum (PAS), surgical injury, adhesions, and thromboembolic complications. Below is a 2024–2025 updated summary of complication rates from major U.S. and international data sources, including NICHD MFMU Network, ACOG/SMFM, and recent population studies.

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Complications After Primary Cesarean Delivery (Updated 2024)

Data from NICHD MFMU Network, AJOG 2020–2024 population studies, and CDC SMM indicators.

Complication	Updated Rate (Approx.)
Endometritis	5–11%
Uterine atony	6–10%
Hemorrhage ≥1000 mL	7–12%
Transfusion (any)	2–4%
Transfusion ≥4 units	0.5–1%
Wound complication	2–7%
Venous thromboembolism	0.1–0.3%
Cystotomy	0.1–0.3%
Ureteral injury	0.01–0.05%
Bowel injury	0.02–0.05%
Broad ligament hematoma	0.1–0.2%
Maternal ICU admission	0.2–0.5%

Fetal scalp laceration remains the most common fetal injury (0.5–1.5%). Other fetal injuries such as long bone or skull fracture remain rare (<0.1%).

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Complications with Increasing Number of Cesarean Deliveries

Risks rise substantially with each additional cesarean delivery, primarily due to dense adhesions, impaired surgical planes, and dramatic increases in placenta accreta spectrum.

Placenta Accreta Spectrum (PAS) Risk (with placenta previa)

Number of Previous Cesareans	Risk of Accreta with Placenta Previa
1	3–5%
2	10–12%
3	35–40%
4	50–60%
5 or more	65–75%

Major Morbidities by Number of Cesareans (2024 SMFM / NICHD updated ranges)

Outcome	Primary	2nd	3rd	4th	5+
Accreta (no previa)	0.2%	0.3%	0.6%	1–2%	2–6%
Hysterectomy	0.3–0.6%	0.4–0.7%	1%	1.5–2.5%	3–9%
Transfusion ≥4 units	1%	0.5%	1%	2–3%	3–10%
Cystotomy	0.1–0.3%	0.2%	0.3–0.5%	1–2%	2–4%
Ureteral injury	0.03%	0.05%	0.1%	0.5–1%	1–2%
Bowel injury	0.03%	0.05%	0.1%	0.3–0.5%	0.5–1%
Endometritis	5–6%	3–4%	3%	3%	2–3%

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Summary (2025)

• Increasing number of cesarean deliveries
• Presence of placenta previa
• Dense adhesions
• Obesity, diabetes, hypertensive disorders
• Emergent cesarean procedures (especially second-stage)

Placenta accreta spectrum now accounts for >60% of peripartum hysterectomies in the U.S., and its incidence is rising in parallel with national cesarean rates.

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