CMV: The dangerous virus most pregnant don't know about

If a pregnant woman contracts CMV from her toddler, her unborn baby could face a slew of health problems. But OBs are divided about whether women should even be told of the risks.

Woman with a doctor Photo: iStock

Liam Levesque’s first day of life was a tough one. Born by emergency Caesarian section at Mount Sinai Hospital in Toronto, at 35 weeks, Liam weighed less than six pounds, was yellow with jaundice, had trouble breathing and needed blood transfusions every two hours to stay alive. He was five days old when doctors got the test results explaining what was wrong: He was suffering from cytomegalovirus, or CMV, a virus he caught in utero, unbeknownst to his mom, Katie.

Liam’s parents, who already had a toddler son, Benjamin, were devastated by their second baby's health issues, and they felt blindsided by the diagnosis. Like most Canadians, they had never even heard of CMV.

“I remember sitting in Liam's room at Mount Sinai and Googling CMV, which was a horrible mistake,” says Katie Levesque. “All these words came shooting out of my phone screen: microcephaly, cerebral palsy, deafness. Everything that came up was just awful.”

CMV is a common virus carried by about half of all adults, but is most dangerous when it's caught from toddlers, who spread the virus through saliva and urine. This is because a toddler's viral load count can remain high—and intensely contagious—for months and even years. CMV rarely causes symptoms in healthy grownups and in fact most people never know they are infected. But the virus is also transmitted through breast milk and blood, and from pregnant women to their fetuses. Unborn babies are most vulnerable early in pregnancy. Infants who contract CMV in utero face risks of neurological damage with lifelong effects. The most common is hearing loss, but developmental delays, intellectual disability, cerebral palsy and visual impairments may also result.

“CMV causes by far more disease in more children than anything else we screen pregnant women or newborns for,” says Dr. Soren Gantt, a paediatric infectious disease specialist at BC Children’s Hospital in Vancouver. “This is a huge public health problem. Every year in Canada there are hundreds of babies who are harmed by congenital CMV infections.”

There is no vaccine to prevent CMV despite the fact that the world’s top health authorities, including the US Institute of Medicine, designated it a priority more than a decade ago. Since then, CMV has continued its churn beneath the radar, overshadowed by buzzier fetal threats like the Zika virus, which can also cause microcephaly. CMV, though, is far more dangerous to Canadian families. While just one case of Zika-related problems in a fetus has been recorded so far in Canada, about 8,000 children here contract congenital CMV every year. Four hundred of those will go on to suffer lifelong consequences, Dr. Gantt says.


The diagnosis stuns most parents. “The parents we see are often angry that no one ever told them this was a possibility,” Dr. Gantt says.

That’s exactly how Katie Levesque felt.

Photo: BAL's Pheonix Lifestyle Photography Photo: BAL's Pheonix Lifestyle Photography

“I appreciate that doctors can’t tell pregnant people everything and there’s so much risk out there. But this should be right up there with, ‘Don’t eat sushi, and don’t eat deli meat, and wash your damn hands,’” she says. “It’s sad that people are more aware of Parvovirus or Zika, a virus that's not even in our country. Pregnant people will cancel trips to Jamaica, but then they’ll share a cup or a fork with their potentially infected toddler.”

The reason so few people know about the threat CMV poses to their unborn babies is because obstetricians around the world are divided on whether to tell expectant patients about it. They are also divided on whether screening pregnant mothers for the virus, which can infect women at any point during pregnancy, is a good idea.


There are two main reasons for the controversial debate, says Dr. Kellie Murphy, a maternal fetal medicine specialist and head of obstetrical research at Mount Sinai Hospital. The first is that there is no treatment yet for a fetus infected with CMV in utero. The second is because figuring out the potential threat CMV presents to a fetus—and to the child that baby will grow into—is a game of uncertain odds.

While about 30 to 40 percent of pregnant women who are infected with CMV for the first time during pregnancy will pass it on to their fetus, only about 20 percent of infected fetuses will develop ensuing health problems. The remaining 80 percent of babies will emerge totally healthy. Physicians have no way of determining with certainty how those odds will impact any given case.

“It’s because of this—that the majority of babies who acquire CMV in utero are going to be healthy and normal—that it’s such a challenging infection to talk about, deal with, and to counsel parents,” Dr. Murphy says. “It’s not a reason to avoid talking about it. But it can be very anxiety-provoking.”

Obstetricians in Canada are free to discuss CMV with patients as they see fit, although mentions of it are rare. In the US, OBs were specifically instructed last year by the American College of Obstetricians and Gynecologists not to counsel patients on CMV, a guideline the college says is based on the fact that no studies have shown that talking about CMV with patients reduces their odds of infection.

By contrast, in Israel, most OBs discuss CMV with their pregnant patients and talk about precautions that could help prevent transmission—hand-washing after diaper changes, and not sharing utensils or mouth kisses with small children. They also screen women for the virus with a blood test at the outset of each pregnancy, between six and ten weeks, explains Dr. Yoav Yinon, a maternal fetal medicine specialist at Sheba Medical Center in Tel Aviv. If the mom-to-be tests negative, doctors do the test every six to eight weeks until she gives birth, says Dr. Yinon. The goal of these tests is to monitor whether the mother becomes infected with CMV over the course of her pregnancy.


But the practice comes with its own set of challenges, Dr. Yinon acknowledges. If a patient tests positive, an amniocentesis, which carries its own risks, must be done to confirm whether the fetus has contracted CMV. “If the fetus tests positive, then the family has to make a decision about whether to continue the pregnancy,” he says. “It’s an ethical question and a big challenge. Their fetus has an 80 percent chance of being healthy and a 20 percent chance of having some issue. But even then, it might only be a hearing problem, so is that grounds to terminate a pregnancy? I believe a woman should decide whatever they want with the information.”

Einat Faibish, a 36-year-old woman who now lives in Thornhill, Ont., had her first child in Israel, where she was tested for CMV. When she immigrated to Canada and became pregnant with her second baby she was surprised to learn she wouldn’t be offered the same test. “I expected more from Canada. Of course knowing more means worrying more. But it also gives you power to make the best decision for you.”

When a fetus is found to be infected, a combination of ultrasounds and MRIs can in some instances help doctors predict what sort of effects, if any, the baby will suffer. However, Dr. Yinon notes, sometimes there is no sign of damage until very late in the pregnancy, and some symptoms, including deafness, can take up to five years to emerge.

For Katie Levesque, there were no signs that anything was amiss with Liam until the last days of her pregnancy, which she says was “completely normal” save for the fact that she had gestational diabetes. (She also had gestational diabetes with her first baby, Benjamin, who is now two.) An ultrasound at 32 weeks to check Liam’s growth didn’t turn up anything odd. But when she went back at 35 weeks—extra ultrasounds are routine for patients with gestational diabetes—the scan picked up an abnormality in the baby’s heart and spleen. The finding launched a terrifying whirlwind that sent Katie and her husband from their home in Sudbury, Ont., to Mount Sinai Hospital in Toronto, where they were told their baby had anemia, an “off-the-charts” enlarged spleen and liver, thickened heart ventricles and, they would later learn, calcifications in his brain. An attempt to give Liam a blood transfusion while in utero led to an emergency C-section. Liam underwent a total of 27 blood transfusions in his first four weeks of life.

Now seven months old, Liam remains on a drug called Valganciclovir, an antiviral given during infancy to reduce some of CMV's long-term effects. Liam’s liver has just begun to function normally. But his development is slow. “I would say he behaves like a four-month-old,” says Katie. “He's not able to roll over and he has poor muscle tone. He has a little trouble holding his head up—he gets tired and gets a little bit floppy,” she says.

Baby in a Bumbo Photo: Katie Levesque

So far, Liam’s hearing has not been affected by CMV. But Katie and her husband struggle with the fuzzy outlook for their youngest son. “Every time we ask a question, it’s pretty much ‘wait and see’,” she says. “Any day we could wake up and his hearing could be gone. He could get to age two or three and not be able to speak. He could have low muscle tone permanently, and require assistance for the rest of his life. The unknown is the worst part,” she says. “We couldn’t be happier with how he’s doing now. But we have no idea what the future holds for him.”

Dr. Gantt and a team of researchers that extends to Ontario are working to reduce that uncertainty for future parents of babies with CMV by advocating that newborns be tested for the virus at birth. Although there is no in utero treatment for CMV that has been proven to be effective, infants respond well to the antiviral drug Liam is taking. And when drugs are administered early, evidence shows that the effects of CMV can be blunted. “They go on to have improved speech and language development, educational and employment outcomes,” Dr. Gantt says.

The reason a test is needed is that babies like Liam, who displayed CMV symptoms at birth, are not the norm. This is another tricky side of CMV.

“Most infected babies don’t have any symptoms at birth,” says Dr. Ari Bitnun, a paediatric infectious diseases specialist at SickKids, The Hospital for Sick Children, in Toronto. Ten to fifteen percent of infants with congenital CMV show symptoms at birth (including microcephaly, eye abnormalities, rashes or an enlarged liver and spleen), but 85 percent do not. And while some in that group might never suffer symptoms, others will experience hearing loss, related speech delays or other random onset effects that can happen anytime until they turn five.


At BC Children’s Hospital in Vancouver, Dr. Gantt is running a pilot program that will test all infants who fail their hearing test. If CMV is the culprit, the infants will promptly receive the antivirals they need in hopes of staving off permanent damage.

Dr. Pranesh Chakraborty, an Ottawa-based paediatrician, medical biochemist at the Children's Hospital of Eastern Ontario and medical director of Newborn Screening Ontario, recently recommended that all Ontario doctors add CMV to the routine panel of tests done on all infants (sometimes referred to as the heel prick tests). The province is considering his recommendation. The goal for both programs is to reduce the lifelong health impacts of CMV.

Among advocates, there is hope that awareness is finally starting to build.

“Now I tell everyone I know about this,” says Liam’s mom, Katie. “Washing my hands after I change a diaper—obviously I do that. But I never used to hesitate to give my son a kiss on the mouth or share my water bottle with him. If someone had told me about CMV, though, I would have been so much more careful.”

Read more: The baby girl I almost had The more you know: The ethics of prenatal testing What prenatal testing can tell you

This article was originally published on Dec 04, 2016

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