Weighing risks and benefits of medication use during pregnancy

Epidemiologists create super database to provide much-needed evidence for which prescriptions are safe, or not, for mom and baby
Sharon Oosthoek
University of Alberta
University of Manitoba
University of Ottawa
University of Saskatchewan
CHU Sainte-Justine
A pregnant woman holds a glass of water in one hand and a few pills in the other

More than 75 percent of pregnant women take medications for which we have little information on the risks or benefits. Clinical trials usually exclude them to protect their babies. The unintended consequence is that they have little evidence-based guidance when it comes to deciding whether to keep taking their medications or start a new therapy during pregnancy.

“We know pregnant women with epilepsy for example will sometimes stop their medication because they’re afraid for their baby, says Anick Bérard, who is a co-leader on the project and a researcher at the Université de Montréal and Montréal’s Centre hospitalier universitaire Ste-Justine.

But what are the consequences — for both mom and baby — if a woman decides to stop her medication? And are there safe alternatives if she does?

Meeting of the minds

This project is a collaboration among these health research organizations across Canada:

Massive Canada-wide data set will provide more reliable answers

Bérard’s co-leader, Sherif Eltonsy, is a researcher at the University of Manitoba and the Children’s Hospital Research Institute of Manitoba. Together, they are building a country-wide database that has already yielded significant insight into these types of questions. They currently have 17 years worth of data on 450,000 pregnancies in the province of Quebec alone, which links medication use at various stages of pregnancy with outcomes.

With new funding from the CFI, they will now add Ontario, Manitoba, Saskatchewan and Alberta to create similar province-specific databases for a total of over four million mothers and children with up to 22 years of follow-up.

Adverse drug events are very rare in pregnancy and might happen well after the child is born, so the team  needs a big data set. Currently, that data is siloed in each province, says Eltonsy.

“You could have records of 100 pregnant women using a particular medication in Manitoba, 200 in Quebec and different numbers in other provinces,” he says. “If we bring those data together, we can see the signal (about adverse reactions) much faster.”

Meticulous fine tuning required to analyze drug data

The funding will also allow the research team to ensure that information is accurate. Provincial records are designed to help governments keep track of payments to doctors and pharmacists, so Bérard and Eltonsy must fine tune that data to analyze drug outcomes.

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That requires careful validation. For example, a database may show that a pregnant woman filled a drug prescription at the pharmacy, but not whether she took it. The team will validate those details. The same holds true for records of birth defects, which must be crossed-checked with hospital and medical charts.

When complete, the Canadian Mother-Child Cohort Active Surveillance Program, as the project is known, will be unique not only for its validated data, but also for its decades worth of information: “A little girl in our database born in 1998 could have a child in our database,” says Bérard.

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