Preconception management
- Baseline CT/MRI should be done in those considering pregnancy with a shunt in situ
- To check baseline ventricular size as during pregnancy ventricles are known to increase in size
- Review potentially teratogenic medications (e.g. anticonvulsants).
- If shunt was inserted for a neural tube defect, there is a 2-3% chance that the baby will also have a neural tube defect.
- Relevant patients require genetic counselling and judicious measures taken to limit the risk factors for neural tube defects (e.g. folate supplementation)
Prepartum management
- Raised ICP can mimic pre-eclampsia/eclampsia and a low index of suspicion is required.
- If increasing intracranial pressure is suspected, a CT or MRI brain should be performed and compared with the baseline.
- If there is no change from preoperative imaging, the shunt should be tapped, the ICP measured and cerebrospinal fluid samples taken for culture.
- If intracranial pressure is normal, and cultures are negative, physiological changes may be responsible.
- Treatment is bed rest and the shunt may be pumped to aid cerebrospinal fluid flow.
- If there is an increase in ventricle size or if intracranial pressure is raised on shunt tap, shunt revision is required.
- In the first and second trimesters, this may be performed as in the nonpregnant.
- In the third trimester, a ventriculoatrial shunt or third ventriculostomy may be considered as an alternative, thereby avoiding the risks of uterine trauma or induction of labor.
Intrapartum management
- Prophylactic antibiotics are recommended during labor and delivery.
- Antibiotics should cover coliforms and be in accordance with local guidelines.
- Colonization with group B streptococcus has been associated with postpartum shunt infection following cesarean section and extended antibiotic regimens should be considered in such cases.
- If the patient has no symptoms of raised intracranial pressure, vaginal delivery is safe and the preferred option, as there is a lower risk of adhesions, which may subsequently result in shunt malfunction and shunt infection.
- A shortened second stage is suggested (2nd stage of labor begins when the cervix is completely dilated (open), and ends with the birth of your baby3)
- as increases in cerebrospinal fluid pressure at this time is greater than during any other Valsalva maneuver and may lead to functional shunt obstruction.
- If a patient becomes symptomatic during labor, cesarean section under general anesthesia is indicated:
- epidural anesthesia is contraindicated with elevated intracranial pressure. (danger of herniation)
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