Study tests predictor for onset of hypertension in pregnancy

CALGARY – Researchers in Calgary are hoping a new study will help them predict which first-time moms are at risk of developing preeclampsia early in their pregnancies.

Preeclampsia, a term for high blood pressure in pregnancy, can be fatal for mothers and their developing babies if it goes untreated. It can also lead to serious complications, including pre-term birth.

Now, researchers with Alberta Health Services (AHS) and the University of Calgary are testing a new prediction algorithm that takes into account a combination of personal history, body mass index, blood pressure, ultrasound findings and indicators of placental function in order to determine preeclampsia risk.

“The prediction tool was developed by the Fetal Medicine Foundation in the U.K. and, while it appears very effective, it has not been validated for use in the Canadian population,” says Dr. Jo-Ann Johnson, AHS Head of Maternal Fetal Medicine at Foothills Medical Centre and the Calgary site lead for the three-year, multi-centre national study.

“We need to have the appropriate evidence in hand to support a change in practice. Although the results of other international studies of the prediction tool are encouraging, we must prove it will work here before we adopt it. If we can reliably identify which women are at increased risk of early onset preeclampsia (before 34 weeks of gestation), we can ensure they get the proper care early on to prevent complications from developing,” adds Dr. Johnson, who is also a professor of obstetrics and gynecology in the University of Calgary’s Cumming School of Medicine.

“It may also alleviate any anxieties that women who aren’t at risk of preeclampsia might have.”

Under the current standard of care, women who are judged to be at risk of early onset preeclampsia are placed on a low-dose of Aspirin, which helps promote normal development of the placenta and reduces the incidence of early onset preeclampsia.

“While there are no apparent risks to the mother or fetus in taking low-dose Aspirin during pregnancy, if there isn’t a need to take it, then I think most women would prefer not to Dr. Johnson says. “We hope the prediction tool will be much more accurate than current methods in identifying mothers at risk.”

Micheline Fulop appeared to be having a normal pregnancy with her first child, right up until the night she went to the Foothills Medical Centre emergency department with stomach pains. It was unclear what her condition was until she returned for an ultrasound the next day, when doctors determined she had a form of preeclampsia.

“I was oblivious to the gravity of the situation until the doctors explained, ‘We have to get this baby out.’ Apparently my liver could have burst, or my retinas detached, or I might have even stroked out,” Fulop says.

Her daughter Ryan, who today is in Grade 1, was born at 33 weeks and weighed four pounds, six ounces. (A baby is considered pre-term if born before 37 weeks of pregnancy.)

“There had never been any high blood pressure issues in the family. This totally blindsided me,” Fulop says. “If research like this can help prevent women from going through what I had to go through, then it’s certainly well worth it.”

Dr. Kara Nerenberg, an AHS specialist in hypertensive disorders of pregnancy, says the prediction tool, if it can be validated, will give doctors an important diagnostic aid.

“Preeclampsia can also contribute to the development of other cardiovascular problems later in life in these women, so prevention will have value that goes well beyond making their pregnancies safer,” says Dr. Nerenberg, a member of the Libin Cardiovascular Institute of Alberta.

As part of the preeclampsia prediction study, Drs. Nerenberg, Todd Anderson, Johnson and other researchers are looking at how well the endothelium – the inner lining of the blood vessels – functions in women at risk of preeclampsia.

Preeclampsia affects about one in every 20 pregnancies. It’s estimated there are fewer than five preventable maternal deaths in Canada every year due to preeclampsia; worldwide it’s a much more significant problem with about 70,000 women dying each year. The Preeclampsia Foundation designates May as Preeclampsia Awareness Month.

The Prediction study is led by Dr. Emmanuel Bujold at Laval University with sites in Montreal, Toronto and Calgary. It is supported by the Canadian Institutes of Health Research. Researchers hope to enrol 7,600 women to the study over the three-year course of the project.

In Calgary, researchers hope to recruit 1,000 first-time moms to the study. If eligible, they’ll undergo a short interview with the study nurse as well as a blood test and some additional ultrasound measurements at the time of their first trimester screen at EFW Radiology. There are also followup surveys and an interview.

For information on how to participate in the study, contact Tess Topor at (403) 943-8382, or email predictioncalgary@gmail.com.

Alberta Health Services is the provincial health authority responsible for planning and delivering health supports and services for more than four million adults and children living in Alberta. Its mission is to provide a patient-focused, quality health system that is accessible and sustainable for all Albertans.

The University of Calgary is making tremendous progress on its journey to become one of Canada's top five research universities, where research and innovative teaching go hand in hand, and where we fully engage the communities we both serve and lead. This strategy is called Eyes High, inspired by the university's Gaelic motto, which translates as 'I will lift up my eyes.' Led by the Hotchkiss Brain Institute, Brain and Mental Health is one of six strategic research themes guiding the University of Calgary toward its Eyes High goals.

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