Pregnancy-related stroke is fortunately a rare event. However, when it occurs there may be implications for the management of the patient and the delivery of the child. The prevalence of intracranial haemorrhage during pregnancy ranges from 0.01% to 0.05% but results in high maternal mortality of 40% to 83% and accounts for 5% to 12% of all maternal deaths during pregnancy.1
Pregnancies (and the perperium) are prothrombotic states. During pregnancy and for approximately 6 weeks after birth, all women are at increased risk of thromboembolic disease. Indeed in the last report on the confidential enquiries into maternal death in the UK, thromboembolism was the leading direct cause of maternal death. The reported incidence of pregnancy related stroke varies widely but probably lies between 11 and 26 deliveries per 100 000.2
showed a rate of ischaemic strokes of 11/100 000 deliveries, with the postpartum period representing the greatest period of risk. The same study also showed that intracerebral haemorrhage occurred at a rate of 9/100 000 of deliveries, again with the highest risk occurring in the postpartum period.
It is important to recognise that strokes occur in young women of childbearing age at a rate of 10.7 per 100 000.4
The risk is elevated during pregnancy for a number of reasons including hypercoagulability, venous stasis and blood pressure fluctuation. Indeed, some estimate that the risk of stroke is 13-fold higher in pregnant than in non-pregnant women, although the rarity of the condition makes the true prevalence a matter of debate.4
As in other patients, it is important when a stroke does occur to establish as quickly as possible if this is due to cerebral ischaemia or haemorrhage. Clinical history or physical examination is insufficiently sensitive to answer this question, so brain imaging in the form of CT or MRI should be carried out as quickly as possible after the onset of symptoms.
Stroke in younger adults is typically categorised as primarily ischaemic or haemorrhagic. Transient ischaemic attacks are rare at a young age. Haemorrhagic strokes are relatively more common. The cause can be found in 55% to 93% of young patients.5–7
MRI is the preferred imaging option in pregnancy. CT scanning can expose the fetus to radiation; however if MRI is not available, the benefit of CT scanning greatly outweigh the risks in this situation and it should be performed.
As is the case with all younger patients with stroke, there should be an extensive diagnostic assessment including vascular studies of the extracranial vessels, cardiac investigations and thrombophilia screening. Intracranial haemorrhage has been estimated to constitute 2% to 7% of the total cases of neurological disorder related to pregnancy.2
In many cases this relates to uncontrolled hypertension.
Haemorrhage from either a subarachnoid bleed or intracerebral bleed takes place most frequently in the second trimester and the postpartum period. A bleed from an underlying aneurysm can take place with equal frequency in all trimesters and the perperium, while bleeding from an underlying AVM occurs most frequently after the first trimester and in the postpartum period.
Subarachnoid haemorrhage (SAH) mostly from aneurysm accounts for 3% of all strokes. A saccular aneurysm will be responsible in approximately 85% of patients with SAH. In 10% of patients, SAH is secondary to non-aneurysmal perimesencephalic haemorrhage.2
There are various ischaemic stroke risk factors that include hypertension, diabetes, sickle cell disease, thrombophilia, smoking, heart disease, multiple gestations and greater parity. In addition, caesarean delivery, alcohol and recreational drug abuse, mainly cocaine, also represent other risk factors. Furthermore, complications of pregnancy such as pre-eclampsia, eclampsia, hyperemesis and disturbance of the electrolyte and fluid balance are major risk factors for stroke.
A study made on a large Swedish cohort of more than 650 000 women with more than 1 million deliveries over an 8-year time period concluded that the greatest risk of ischaemic and haemorrhagic cerebral events was in the 2 days before and 1 day after delivery, with an increased but declining risk over the subsequent 6-week postpartum period. It has been estimated that there is a mortality of 10% to 13% following pregnancy-related stroke, and that this is disproportionately higher in black women, in older patients and in those with no parental care.8 9
Antiphospholipid syndrome can be triggered by pregnancy. This may present with stroke, which may be either arterial or venous. Diagnosis rests on the detection of one or more anti-phospholipid antibodies; lupus anticoagulant, anti-cardiolipin antibody and anti-B2 glycoprotein.10
Women who are pregnant or in the postpartum period account for 10% to 25% of patients with thrombotic thrombocytopaenic purpera (TTP). TTP may present with a wide variety of neurological symptoms including strokes, transient ischaemic attacks, fluctuating neurological symptoms, headaches, seizures and confusion.10
Peripartum or postpartum angiopathy, a cerebral dysregulation syndrome affecting large and medium sized cerebral artery, may be associated with haemorrhagic or ischaemic strokes. The clinical picture typically occurs in women aged 20–50 years and is usually one of abrupt onset with severe thunderclap headaches, seizures and focal neurological deficit. The imaging findings may often be suggestive, as white matter changes have a posterior emphasis and are usually not as extensive compared with eclampsia. Diffusion-weighted MRI may help in differentiation.11–14
- Although uncommon, the development of stroke during pregnancy and purperium can be a challenging diagnostic and management problem. For this reason we advise that such patients are managed in a specialised multidisplinary unit with rapid access to expertise in obstetric, neurological, neuroradiological and rehabilitation services.
- Strokes can happen at any time. The clinical presentation is similar to that seen in patients who are not pregnant; however, these symptoms can mimic those seen in pre-eclampsia and eclampsia, and because of that the possibility of stroke may be overlooked.
- It is prudent to counsel all patients and especially those with relevant risk factors to seek care for any symptom that may be associated with stroke: headaches, visual changes, epigastric pain, seizures, nausea, vomiting or neurological defects (focal or global). Severe hypertension and widened pulse pressures are also symptomatic of stroke.