What is the recommended delivery route for pregnant women with a maternal cerebral aneurysm based on aneurysm size and location?

Delivery Route for Pregnant Women with Cerebral Aneurysms

For pregnant women with cerebral aneurysms, vaginal delivery with a shortened second stage is recommended for small aneurysms (<5mm), while cesarean section should be performed for aneurysms ≥10mm or when the aortic root diameter is ≥4.5cm in patients with associated aortic pathology. 1, 2

Risk Stratification by Aneurysm Size

Small Aneurysms (<5mm)

• Vaginal delivery is appropriate with specific modifications to minimize hemodynamic stress 2
• These aneurysms have virtually no rupture risk during pregnancy, with annual rupture rates approaching 0.05% per year 3
• The presence of a small cerebral aneurysm is not an automatic contraindication to Valsalva maneuver during pushing 2

Medium to Large Aneurysms (5-10mm)

• Individualized approach required based on aneurysm location, morphology, and maternal neurological status 2, 4
• Consider vaginal delivery with assisted second stage to minimize pushing and Valsalva maneuvers 1
• Epidural or spinal anesthesia may be avoided in some cases due to concerns about hemodynamic fluctuations 1

Large Aneurysms (≥10mm)

• Cesarean section is strongly recommended to avoid hemodynamic stress from labor and Valsalva 1, 2
• Annual rupture rate increases significantly to approximately 1% per year for aneurysms ≥10mm 5
• Maternal mortality from rupture during pregnancy can reach 70% 5

Delivery Management Protocol

For Planned Vaginal Delivery (Small Aneurysms)

• Shorten the second stage of labor through assisted delivery (forceps or vacuum) 1
• Position patient on left side or semi-erect to minimize aortic and intracranial pressure changes 1
• Avoid excessive pushing and repeated Valsalva maneuvers 1
• Maintain strict blood pressure control throughout labor 4

For Cesarean Section (Large Aneurysms)

• Perform cesarean delivery for obstetric indications when aneurysm size warrants concern 1
• General anesthesia may be preferred over neuraxial techniques for large aneurysms to maintain better hemodynamic control 2
• Have neurosurgical team available for immediate intervention if rupture occurs 6, 7

Critical Timing Considerations

Ruptured Aneurysms During Pregnancy

• Aneurysm obliteration should be prioritized first, followed by delivery 8
• If fetus is viable (≥36 weeks), emergency cesarean section followed immediately by aneurysmal treatment is the widely accepted strategy 6, 7
• Combined neurosurgical and obstetric care is essential 7, 4

Unruptured Aneurysms

• Timing of delivery should be based primarily on obstetric indications for small stable aneurysms 3
• For large unruptured aneurysms, consider prophylactic treatment before delivery if technically feasible 8

Common Pitfalls to Avoid

• Do not automatically recommend cesarean section for all cerebral aneurysms - size and rupture risk must guide decision-making 2
• Avoid applying rupture statistics from larger aneurysms to small ones - aneurysms <5mm have negligible rupture risk even with Valsalva 3
• Do not delay neurosurgical intervention in ruptured cases to attempt vaginal delivery - maternal stabilization takes priority 8, 6
• Recognize that excessive pushing during second stage increases intracranial pressure - always plan for assisted delivery when vaginal route is chosen 1

Multidisciplinary Planning Requirements

• Pre-delivery imaging with MRI to assess aneurysm size, location, and morphology 4
• Blood pressure optimization throughout pregnancy and delivery 4
• Neurosurgical consultation for all aneurysms ≥5mm to establish emergency treatment plan 6, 7
• Anesthesia planning to determine optimal approach (general vs. neuraxial) based on aneurysm characteristics 2