We recently reported on a new peer‑reviewed journal article examining congenital Lyme disease. The paper represents one of the most significant scientific reviews of this topic to date. Here, long-time advocate Bruce Fries takes a closer look at what the authors found and why it matters.

By Bruce Fries

A groundbreaking scientific report emerging from the June 2022 Banbury Conference at Cold Spring Harbor Laboratory is reshaping the medical understanding of Lyme disease in pregnancy.

It directly challenges a key assertion in the 2020 IDSA/AAN/ACR Lyme disease guidelines that “Lyme disease in pregnancy has not been found to result in congenital infection.”

The newly published peer-reviewed paper, “Perinatal transmission of Borrelia burgdorferi: advancing scientific and clinical understanding of Lyme disease in pregnancy,” concludes that the bacterium responsible for Lyme disease can cross the placenta and may contribute to serious adverse outcomes in pregnancy and infancy.

The report states unequivocally:

“The totality of existing evidence indicates that Bb can cross the placenta and may be associated with adverse pregnancy outcomes including fetal/infant morbidity and mortality.”

A landmark scientific turning point

The Banbury Conference brought together leading international experts from academia, clinical medicine, and government agencies to review decades of research on Lyme disease transmission during pregnancy. The resulting publication represents the most comprehensive synthesis of evidence to date.

The authors emphasize that perinatal transmission is not a theoretical concern, but a documented biological phenomenon:

The Banbury findings underscore that Lyme disease in pregnancy is both a public health issue and a research priority:

Evidence of risk to pregnancies and infants.

The report documents a wide spectrum of adverse outcomes associated with gestational Lyme disease, including:

• Miscarriage and stillbirth
• Preterm birth
• Neonatal death
• Neurologic and cardiac abnormalities

The authors note, “A wide range of adverse pediatric outcomes reported with LD in pregnancy include preterm birth… neurologic abnormalities… and perinatal death.”

Crucially, infection may occur even when the mother has no symptoms:

“The spirochete can be transmitted to the placenta or fetus in the absence of maternal clinical signs and symptoms.”

In one study cited in the report:

“5% of placentas harbored Bb spirochetes, implying fetal transmission.”

Diagnostic and clinical blind spots

The Banbury report highlights major challenges in diagnosing Lyme disease during pregnancy:

• Up to 40% of cases may lack the characteristic rash
• Serologic testing may be negative despite infection
• Many women are asymptomatic or misdiagnosed

The authors warn:

“This poses a serious diagnostic dilemma.”

They further caution that reliance on standard testing may lead to missed cases of congenital infection.

Treatment gaps and persistent infection

Even when Lyme disease is diagnosed and treated, risks may remain. The report notes:

“Bb has been identified in placental… and fetal tissue from mothers who received a single course, or in some cases multiple or prolonged courses of antibiotic therapy.”

This raises critical questions about current treatment protocols and their effectiveness in preventing fetal transmission.

Direct challenge to current guidelines

The Banbury findings stand in stark contrast to the IDSA/AAN/ACR guideline statement denying congenital infection.

A formal retraction request submitted to the guideline authors in October 2021 underscores this discrepancy, asserting that the statement “Lyme disease in pregnancy has not been found to result in congenital infection” is a factual error with serious implications for patient care. The request emphasizes that such misinformation risks delaying diagnosis and treatment for pregnant women, thereby increasing the likelihood of harm to both mothers and their children.

Public health complications

The Banbury report makes clear that the lack of recognition of congenital Lyme disease has hindered progress:

“No international surveillance system exists to track cases of congenital Lyme disease.”

And critically:

“A standardized case definition for identifying congenital LD has yet to be delineated.”

Without surveillance, standardized definitions, or updated guidelines, the true scope of the problem remains hidden.

Urgent call for action

The Banbury Conference authors call for immediate and coordinated action, including:

• Longitudinal studies of pregnant women and exposed infants
• Improved diagnostic tools
• Development of clinical guidelines for pregnancy and neonatal care
• Establishment of registries and surveillance systems

They stress:

“Comprehensive guidelines for diagnosis, treatment, and long-term management of pregnant women with LD and newborn infants are urgently needed.”

Conclusion

The Banbury report represents a watershed moment in Lyme disease research—one that fundamentally challenges outdated assumptions and calls into question current standards of care.

By confirming that Lyme bacteria can cross the placenta and may harm developing fetuses, the findings demand a reassessment of clinical guidelines that continue to deny congenital infection.

As the authors conclude, the science is clear, but the work ahead is substantial:

“Many fundamental research questions remain.”

For pregnant women and their children, the stakes could not be higher.

Bruce Fries, founder and president of the Patient Centered Care Advocacy Group, is based in the Washington DC area.