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A scientist who co-authored a recent Public Health Agency of Canada study on the impact of Lyme disease during pregnancy says the illness can have fatal consequences for a developing fetus if the mother goes untreated.

“Miscarriage, newborn death, and newborns with respiratory problems or jaundice have been found to occur,” said American epidemiologist Alison Hinckley.

But the Centers for Disease Control and Prevention scientist says more research is needed to show a definitive link between Lyme disease and pregnancy complications, including whether the tick-borne illness can be passed from mother to baby in the womb.

Hinckley and four Public Health Agency of Canada scientists authored a recent report that reviewed 59 cases of pregnant mothers carrying Lyme disease and their pregnancy outcomes. The results were published in the November 2018 peer-reviewed science journal PLOS One, showing that 36 of the 59 fetuses had been harmed. Complications ranged from miscarriage and stillbirth to congenital abnormalities, respiratory distress and heart abnormalities.

“It is clear, however, that pregnant women who suspect that they might have contracted Lyme disease should see their health-care provider as quickly as possible to receive appropriate treatment and reduce the chance of poor fetal outcomes,” said Hinckley.

PHAC denied requests from the Herald to speak with any of the agency’s four scientists that coauthored the study. The Herald contacted the study’s lead author Lisa A. Waddell by email and phone but did not get a response.

The question remains, why do pregnant mothers with untreated Lyme disease risk harming their unborn baby?

Determining cause

The authors of the systematic review failed to provide a specific cause for any of the 36 pregnancies resulting in harm to the fetus, nor could they definitively say whether Lyme disease factored in any of the congenital malformations. The study couldn’t rule out transplacental transmission, that the bacteria causing Lyme disease, B. burgdorferi, could be passed from mother to baby in utero.

“It is biologically plausible that transplacental transmission of B. burgdorferi occurs given our understanding of transplacental spirochete transmission for other species of spirochetes (T. pallidum) in humans,” said the study. “However, the evidence in this systematic review on congenital malformations does not provide sufficient evidence to exclude or confirm a role for B. burgdorferi in congenital malformations.”

The study calls for more research to settle the debate.

But the topic of in utero transmission of Lyme disease is not new and cases of it have been documented over the decades. As far back as 30 years ago the federal Department of Health acknowledged it as a legitimate form of transmission, stating in a June 1988 Canada Diseases Weekly Report that, “Transplacental transmission of B. burgdoferi has been documented and may be associated with an increased risk of adverse pregnancy outcome.”

That it occurs is not up for debate, argues biologist Vett Lloyd of the Mount Allison University Lyme Research Network.

“There is evidence from epidemiological studies that the Lyme disease bacteria can be transmitted from mother to child,” said Lloyd, who’s also a leading Canadian tick expert. “There is also evidence from case studies of this.

“But what we don’t know are the answers to questions important to pregnant mothers: How often does this occur? Is it with every pregnancy when the mother is infected or one in 10? One in 100? One in a million?”

We know what we don't know

Ultimately, the study illustrates how much researchers don’t know about the impact of Lyme disease in pregnancy, she says. If in utero transmission occurs and the B. burgdorferi bacterium passes the placenta to the baby what happens then? In children and adults Lyme disease has the potential to target every vital organ.

“If it is transmitted in utero to a child, that increases the number of people who can potentially be infected,” said Lloyd. “There is no reason to think that a newborn would be any less affected by Lyme disease than an adult — the opposite would be a reasonable assumption.

“This problem is compounded if a mother doesn’t know that she is infected with the Lyme disease bacteria, becomes pregnant while being treated or becomes infected while pregnant.”

The Herald made several attempts to speak to Dr. Robert Strang, the province’s chief medical officer of health, about the findings of the study but he declined to be interviewed. In an email statement Strang reaffirmed one of the main conclusions of the study: “There is not enough evidence to confirm that Lyme disease during pregnancy has any adverse effect on the fetus, Lyme disease can be effectively treated in pregnancy and that further research is needed,” stated Strang.

Strang’s statement also defends the way the province treats Lyme disease, including in pregnant mothers. “Nova Scotia’s approach to the diagnosis and treatment of Lyme disease, including Lyme disease in pregnancy, is based on current scientific evidence and is consistent with national and international evidence-based guidelines.”

Sue Faber, co-founder of LymeHope and a registered nurse, says PHAC is ignoring decades of documented proof of transplacental transmission and insists it’s only a matter of time before the medical community is forced to acknowledge it as a legitimate form of transmission that results in congenital Lyme disease — babies being born with the disease.

Over the year, her Lyme advocacy group has gotten thousands of letters from people across the country convinced family members have fallen victim to congenital Lyme disease. She also says a follow up study is needed to look at some of these families.

When the time comes that the medical community accepts that babies can contract the disease in utero it will be “a game changer,” she says.

“For Lyme disease to be passed from mother to child in pregnancy challenges and deconstructs the status quo from Lyme being only a tick-borne disease to one that can be transmitted from human-to-human, mother-to-baby,” said Faber. “Once we acknowledge that this disease changes and we have a big problem on our hands.”

Anna Maddison, spokeswoman for PHAC, admits more research is required to better understand if there may be adverse effects of Lyme disease during pregnancy. She did not say what current or future research is planned to target questions around transplacental Lyme disease.

But Maddison did point to a new Pan-Canadian Lyme Disease Research Network and that part of its research mandate will include working with patients and families to help address gaps in knowledge. The Society of Obstetricians and Gynecologists of Canada is also reviewing current evidence on the effects of Lyme disease and other tick-borne diseases on pregnancy, she says.

“The aim is to equip health-care providers and women with evidence-based information and tools on Lyme disease and other tick-borne diseases during pregnancy,” said Maddison.

But Faber says she sees little evidence that PHAC is responding to the findings of the study with the urgency it deserves.

“Medical and scientific research needs to follow the precautionary principal,” said Faber. “If there’s a risk, it needs to be addressed. We have identified that human-to-human transmission is possible, and even if it’s plausible there’s a social responsibility to protect the public from exposure to harm.”

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