Dr. Janine Hutson: Mapping the Uncharted Territory of CFTR Modulators and Pregnancy

A generation ago, many people with cystic fibrosis (CF) weren’t expected to reach adulthood, making conversations around pregnancy far less common than they are today. Today, thanks to CFTR modulators, medications that target the underlying cause of the disease, more people with CF are starting families than ever before. But with this progress comes new uncertainty: how can these life-changing medications be used safely during pregnancy?

Dr. Janine Hutson, an obstetrician-gynecologist (OBGYN) specializing in high-risk pregnancies, at London Health Sciences Centre and Assistant Professor at Western University, is working to answer that question.

With support from Cystic Fibrosis Canada, Dr. Hutson is studying how CFTR modulators move between a pregnant parent and their developing baby. Her goal is to generate the evidence needed to guide safe and effective dosing during pregnancy for both parent and child.

Why this research matters now

“CFTR modulators have changed the way the disease is managed,” Dr. Hutson explains.  “We’re seeing more patients of childbearing age being able to become pregnant.”

Many people with CF who are taking modulators are choosing to stay on them during pregnancy, even though the safety through pregnancy isn't fully understood. But, coming off modulators can lead to a decline in health, leaving patients faced with difficult decisions regarding family planning.

Yet there is still limited evidence on how these medications affect a developing fetus. Some early signals, such as changes in liver function or development of cataracts, have been observed in a small number of exposed infants, but more research is needed to understand what this might mean for a baby's long-term health.

Studying the placenta to understand drug transfer

 Dr. Hutson’s research uses donated human placentas to directly measure how medications cross from parent to fetus.

“The placenta is the most species-specific organ,” she explains, with blood flow and the structure of the organ being essential to studying it,

In the lab, her team is recreating how blood flows through both sides of the placenta to study how these drugs move in real time. This allows them to see exactly how much of each CFTR modulator would reach the developing baby.

Her early findings confirm that these drugs do in fact cross the placenta, highlighting the importance of understanding appropriate dosing.

Why dosing in pregnancy is complex

Pregnancy changes how the body processes medications in important ways.

“In early pregnancy, you may be similar to a non-pregnant adult,” Dr. Hutson explains. But as pregnancy progresses, things shift.

Blood volume increases, and the fetus develops its own circulation. As a result, the same medication dose may not have the same effect.

“For some medications, you might need a higher dose to achieve the same levels in the blood,” she says. This means you can’t assume the same dose used outside of pregnancy will be safe during pregnancy.

Toward personalized dosing for parent and baby

Dr. Hutson’s ultimate goal is to translate this data into a practical clinical tool.

Her team is developing a computer model that simulates how CFTR modulators move through the body during pregnancy. This tool could help clinicians determine the right dose for each patient, balancing effectiveness for the parent with safety for the baby.

Dr. Hutson hopes this will support parents with CF to stay on medications that keep them healthy, while reducing potential risks for their baby.

At the same time, the research could open the door to a new possibility: treating CF before birth.

“We now have the tools to potentially change somebody’s life right from the start,” Dr. Hutson says.

In some cases, this could mean giving medication to a pregnant parent, so their baby with CF begins receiving treatment in utero.

Looking ahead

Pregnancy in CF is still, as Dr. Hutson puts it, “unknown territory.”

But with more people living longer and healthier lives, it's a territory worth exploring, and Dr. Hutson is determined to chart it.

Her work is helping ensure that families living with CF can make informed decisions about pregnancy, with confidence that their medications are working for both them and their baby.