Rate of stroke three times higher among pregnant women: study

Anna Jodhi was 16 weeks pregnant when she had her first stroke. Five weeks later, she had her second.

For the healthy 27-year-old, the diagnosis came as a shock. She experienced a few mild headaches during her pregnancy and only decided to head to hospital when she started seeing dark spots in her vision during a work presentation.

That’s when doctors administered and MRI and delivered the news.

“It was nothing scary or weird,” Jodhi, a scientist who works in health care, recalled. “I didn’t feel any pain. I was not blurring my speech. My face was not dropping.”

Jodhi’s experience may sound unusual. But according to a new Canadian study, the rate of stroke is three times higher among pregnant women than non-pregnant women of the same age, an alarming finding that researchers say isn’t completely understood.

The study, published Friday in the International Journal of Stroke, analyzed numerous international studies from the last 27 years that addressed stroke incidence during pregnancy.

Researchers found that about 30 out of every 100,000 women will experience a stroke at some point during pregnancy. The likelihood of suffering a stroke is highest in the period immediately before and after birth, and the incidence of stroke is three times higher among pregnant women than non-pregnant women.

Jodhi’s back-to-back strokes changed the course of her pregnancy. She left her job on a short-term leave, temporarily lost her driver’s licence and had regular checkups to monitor the health of both her and her unborn child.

“You never think it will ever happen to you,” she said. “It was just a slap, really.”

Fortunately, her baby was born without complications. But Jodhi lives with a blind spot in her right eye and sometimes faces accusations that what she suffered wasn’t really a stroke.

“This is not an invented story,” she said. “People do not realize that strokes can happen in young people, in pregnant people.”

Why stroke risk is higher in pregnancy

Study co-author Dr. Rick Swartz, the director of the Stroke Research Unit at Sunnybrook Health Sciences Centre, points out that in absolute terms, stroke in pregnancy is a relatively rare event, as it affects only 0.03 per cent of women.

“Three times a small number is still a small number,” he told CTVNews.ca. “We don’t want to scare women.”

Still, he said, strokes do happen both during pregnancy and afterward, and women need to be aware that the risk remains elevated for six or even 12 weeks after birth.

Dr. Swartz said there are a few reasons why women are at an increased risk of stroke during pregnancy. For one, many women develop high blood pressure or diabetes during pregnancy. While the conditions often resolve after delivery, they increase the risk of stroke during pregnancy.

Some women develop a more severe condition called pre-eclampsia, which is an abrupt and potentially deadly spike in high blood pressure that requires an early delivery of the baby.

As well, the female body simply forms more clots during pregnancy to protect itself from too much bleeding during delivery, Dr. Swartz explained, and clots can travel to the brain and become strokes.

The global meta-analysis found that geography may play a factor, too. Researchers found that some countries that offered universal prenatal care reported lower rates of stroke in pregnant women. However, researchers cautiously describe the relationship as a “potential trend.”

How to limit risk

Dr. Swartz says there are a number of things that women can do to decrease their risk of stroke in pregnancy – and afterwards too. They include first and foremost not smoking, getting up and moving as much a possible during the pregnancy, and following a healthy diet.

They should also ensure they attend all their doctors’ appointments so they can be screened for high blood pressure and protein in the urine, which can be signs of pre-eclampsia.

As well, they should be on the lookout for any worrying symptoms even after delivery, such as unexplained intense headaches, sudden severe swelling, or a sudden inability to move or see.

“These are red flags to seek medical help by calling 911,” Dr. Swartz said.

The study was funded by Heart & Stroke, Canadian Institutes of Health Research, Heart & Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Health Sciences Centre Department of Medicine and the University of Toronto Department of Medicine.