Preeclampsia (a high blood pressure disorder in pregnancy) increases the risk of pregnancy-associated stroke (PAS) up to 6-fold. A large review of women with preeclampsia who had PAS found that they were more likely to have severe preeclampsia, infection, chronic high blood pressure, or underlying conditions predisposing them to clotting or bleeding problems.
Preeclampsia is a high blood pressure disorder in pregnancy. It is thought to occur when the placenta does not implant properly and the placental blood vessels develop abnormally. The cause is not clear, but preeclampsia has been linked to a number of factors including poor nutrition, obesity, abnormalities in the immune system or genetic causes.
Preeclampsia usually appears in the later stages of pregnancy, at least after 20 weeks. Patients have a collection of abnormalities including raised blood pressure, protein in the urine and swelling of the feet, legs, hands and face. They may also notice sudden weight gain, headaches or blurring of vison. Preeclampsia can have serious consequences for the health of the mother and baby. Poor blood supply to the placenta may affect the baby’s growth. In severe cases, the mother may experience seizures, stroke or heart failure. It is important to monitor pregnant women carefully to watch for any signs of preeclampsia.
Stroke is caused when a blood vessel in the brain is blocked, or there is bleeding into the brain. The outcome of a stroke depends on which part of the brain is damaged. Although most common in the elderly people, changes during pregnancy can increase the chance of stroke. Pregnancy-associated stroke (PAS) is defined as stroke occurring during pregnancy or up to 6 weeks after delivery. PAS can occur without underlying preeclampsia, but preeclampsia increases the risk of PAS up to 6-fold. If the two conditions occur together there is an increased risk of complications and death.
Preeclampsia affects 3-8% of pregnancies, but the overall occurrence of PAS is low (34.2 per 100,000 deliveries). Because PAS is rare, it is difficult to predict which preeclampsia patients are at highest risk of developing PAS. A large study which set out to find what risk factors put women with preeclampsia at highest risk of PAS was recently published in the journal Stroke.
The researchers used the New York State Department of Health inpatient database to identify all women between 12-55 years of age admitted with preeclampsia between January 2003 and December 2012. Women without preeclampsia were not included in the study, regardless of whether they had PAS.
During the period studied, over 88,000 women were admitted to hospital in New York State with preeclampsia. Of these, 197 had PAS. Overall, compared with the over 88,000 women who did not have PAS, the group of women with PAS were older, included a higher proportion of black race, a lower proportion of Hispanic ethnicity and a higher proportion of severe preeclampsia or eclampsia. This was consistent with observations of previous studies.
The researchers were particularly interested in finding risk factors that could be treated or modified. Each patient with preeclampsia and PAS was matched to 3 control patients of the same age, race/ethnicity and insurance status, selected randomly from the pool of women with preeclampsia without PAS. These matched patient groups were then compared for risk factors that had been previously linked to preeclampsia with PAS.
When compared with the control group, the group of women with preeclampsia and PAS were more likely to have: severe preeclampsia; infections present on admission to hospital (especially urinary tract infections); underlying conditions predisposing to thrombosis (clotting) or coagulation (bleeding); chronic high blood pressure.
The researchers suggest that women who develop preeclampsia should be screened to check if they have any of these treatable risk factors for PAS. They recommend further studies to confirm their findings in order to develop actions aimed at preventing PAS in patients with preeclampsia.
Written By: Julie McShane, Medical Writer