Is a computed tomography (CT) scan safe for postpartum women?

CT Scanning in Postpartum Women

Yes, CT scans can and should be performed in postpartum women when clinically indicated—there are no radiation safety concerns for the mother or nursing infant, and CT is often the most appropriate diagnostic tool for life-threatening postpartum complications.

Safety Profile in the Postpartum Period

CT imaging is safe and appropriate for postpartum women without the radiation concerns that exist during pregnancy. 1 The postpartum period eliminates fetal radiation exposure concerns, making CT a valuable diagnostic tool when clinically indicated. 2

Maternal Radiation Exposure

• The maternal effective dose from CT imaging poses no meaningful cancer risk and is well within acceptable limits for diagnostic imaging. 3
• There are no radiation dose restrictions for postpartum women, unlike during pregnancy where cumulative exposure should remain below 50 mGy. 3

Breastfeeding Considerations

• Breastfeeding can continue immediately after CT with iodinated contrast—less than 1% of iodinated contrast is excreted into breast milk and less than 0.01% appears in breast milk, with minimal absorption into the infant's gastrointestinal tract. 1, 3
• No interruption of breastfeeding is necessary after contrast administration. 4

Clinical Indications for CT in Postpartum Hemorrhage

Primary (Early) Postpartum Hemorrhage (<24 hours)

CT with IV contrast is the primary imaging modality for detecting active hemorrhage, localizing bleeding sources, and identifying complications when conservative management fails. 1

Key Diagnostic Capabilities:

• Active extravasation detection: Multiphasic CT demonstrates 97% accuracy for detecting the site of active bleeding, with extravasation visible in 41-74% of postpartum hemorrhage cases. 1
• Vascular complications: CT identifies pseudoaneurysms (showing pseudoaneurysmal sac as a specific finding), arteriovenous malformations, and can localize feeding arteries for treatment planning. 1
• Hematoma characterization: CT delineates supra-umbilical and perivaginal space hematomas and their relationship to adjacent organs (supralevator versus infralevator location). 1
• Uterine atony assessment: Although clinically diagnosed, CT can detect focal or diffuse arterial or venous oozing and hematoma within an enlarged uterus. 1

Specific Clinical Scenarios:

• Hemodynamically stable patients with ongoing hemorrhage: Multiphasic CT (noncontrast, arterial, and portal venous phases) localizes bleeding for targeted intervention. 1
• Persistent hemorrhage after empiric embolization: CTA is specifically indicated to identify ongoing extravasation. 1
• Suspected intra-abdominal hemorrhage: CT is particularly valuable when bleeding extends beyond the pelvis. 1

Secondary (Delayed) Postpartum Hemorrhage (>24 hours to 6 weeks)

CT remains valuable for delayed hemorrhage, though ultrasound is typically the initial modality. 1, 5

Diagnostic Applications:

• Retained products of conception (RPOC): Difficult to differentiate from blood products even on multiphase CT, though CT can identify associated complications. 1
• Endometritis and complications: CT shows thickened heterogeneous endometrium with fluid, gas, and debris, and can identify parametrial abscess, infected hematoma, or ovarian vein thrombosis. 1
• Gestational trophoblastic disease: Appears as heterogeneous hypervascular intrauterine mass with central necrosis, distinguishable from RPOC when invasion of adjacent organs or distant metastasis is present. 1

Technical Considerations and Pitfalls

Contrast Protocol

• CT with IV contrast is preferred—there is little clinical utility in noncontrast CT or CT with and without contrast for active hemorrhage evaluation. 1
• Multiphasic CTA (noncontrast, arterial, portal venous phases) provides optimal detection of extravasation. 1

Common Diagnostic Pitfalls:

• False positives: Dilated tortuous hypertrophic uterine arteries can mimic extravasation on CTA. 1
• False negatives: Slow intermittent hemorrhage from atony may not show active extravasation. 1
• Vascular abnormalities: CTA cannot reliably distinguish acquired pseudoaneurysms from subinvolution of placental bed vessels or assess severity/need for intervention. 1
• RPOC differentiation: Remains challenging even on multiphase CT, often requiring correlation with clinical findings and beta-HCG levels. 1

Other Postpartum Complications Evaluated by CT

CT provides rapid and reliable evaluation of major pelvic organs for multiple postpartum complications beyond hemorrhage. 6, 2

• Infectious complications: Abscesses, endometritis, and thrombophlebitis. 6, 2
• Life-threatening sequelae: HELLP syndrome (hemolysis, elevated liver enzymes, low platelet count), disseminated intravascular coagulation. 6, 2, 5
• Structural complications: Uterine perforation, uterine rupture, uterine inversion (subacute partial inversions detected as concavity of uterine fundus). 1, 2, 5
• Extrauterine sources: Rectus sheath hematoma, direct arterial injuries, bladder flap hematoma. 5
• Incidental findings: Post-partum cardiomyopathy and heart failure may be first identified on CT. 2

Comparison with Alternative Imaging

When MRI May Be Preferred:

• Deep-seated pelvic hematomas: Noncontrast MRI provides superior spatial resolution for localizing hematomas (supralevator versus infralevator). 1
• Uterine dehiscence versus rupture: MRI can distinguish these when ultrasound or CT findings are confusing. 1
• RPOC characterization: MRI shows variably enhancing intracavitary mass with variable myometrial thinning. 1

Limitations of MRI:

• Less commonly used in life-threatening early postpartum hemorrhage due to limited access and longer acquisition time. 1
• Cannot reliably distinguish acquired pseudoaneurysms from failure of obliteration of placental bed vessels. 1

Role of Ultrasound:

• Often the initial imaging modality, particularly for delayed hemorrhage. 1, 5
• Limited by inability to reliably assess severity of vascular abnormalities or need for intervention. 1
• Doppler can detect vascularity in RPOC and swirling flow in pseudoaneurysms, but marked vascularity can mimic pseudoaneurysm. 1