Can Babesia Be Passed to a Baby During Pregnancy?
No symptoms in the mother
Babies become ill weeks later
The infection is often missed
Babesia pregnancy is a rare but important cause of congenital infection that may go unrecognized until after delivery.
In two reported cases, mothers unknowingly transmitted this Babesia parasite to their newborns despite minimal or delayed symptoms.
Babesia infects red blood cells and can lead to anemia, fever, and serious complications in infants.
This pattern reflects a broader issue seen in tick-borne illness—when infections are not fully evaluated during pregnancy, complications may appear later.
Here’s what these cases reveal.
How Babesia Is Transmitted During Pregnancy
Babesia can be transmitted through:
- Tick bites
- Blood transfusions
- Vertical transmission during pregnancy
The CDC recognizes that in utero transmission can occur.
Because Babesia shares a vector with Lyme disease, co-infection with other tick-borne coinfections is common.
This pattern is often missed because treatment may target Lyme disease while leaving Babesia untreated.
Case 1: Babesia Pregnancy in the Third Trimester
The first mother, living in an endemic region, was diagnosed with Lyme disease at 32 weeks after developing an erythema migrans rash.
She was treated with amoxicillin.
However, amoxicillin does not treat Babesia or other coinfections such as Anaplasmosis or Ehrlichia.
Laboratory testing later showed IgM positivity followed by IgG conversion, suggesting a recent infection.
Despite this, treatment was not expanded.
The infant initially appeared well but was diagnosed and treated four and a half weeks after birth.
The mother was never treated for Babesia.
Case 2: Delayed Recognition After Delivery
The second mother presented with fever and muscle aches and was diagnosed with Lyme disease late in pregnancy.
Initial testing for coinfections was negative.
Her newborn appeared healthy at birth but later tested positive for Babesia microti by PCR testing.
At 18 days of age, parasites were visible in the infant’s red blood cells.
The infant required hospitalization, antiparasitic therapy, and blood transfusion.
Follow-up testing confirmed that the mother had active Babesia infection, yet she was not treated.
Why Babesia Pregnancy Is Missed
Diagnosis is often delayed because:
- Mothers may have mild or nonspecific symptoms
- Testing may initially be negative
- Treatment focuses on Lyme disease alone
- Symptoms in newborns may not appear immediately
This reflects a broader diagnostic gap seen in delayed Lyme disease diagnosis, where timing and incomplete evaluation lead to missed infections.
Why This Matters
Babesia pregnancy can lead to delayed illness in newborns—even when the mother appears stable.
Failure to recognize maternal infection may result in preventable complications, including anemia and the need for transfusion in infants.
Early recognition allows for monitoring and timely treatment.
Clinical Perspective
Pregnant patients with Lyme disease should be evaluated for coinfections, particularly in endemic regions.
Standard Lyme treatments such as amoxicillin do not address Babesia.
Recognizing coinfection risk is critical for preventing congenital transmission.
Clinical Takeaway
Babesia pregnancy is uncommon but clinically significant.
Maternal infection may go untreated while newborns develop symptoms weeks later.
Clinicians should consider Babesia in pregnant patients with tick exposure, even when symptoms are mild or testing is initially negative.
Related Reading
References
Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.
Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention
I’m extremely interested in this topic. I have tested positive for Babesiosis. I have elevated HLA and C-Reactive Protein levels that fluctuate off the charts. I now have a child with Babesia and is suffering. He is now being treated, I was not. Furthermore, I suspect my other two children also have it as well. We are awaiting test results. What I’m trying to find out, is this:
1. Could my Babesia have been spread to ALL my children? Why are we not screening for this?
2. How likely is it congenital versus environmental?
3. What are long term effects of untreated Babesia?
My family lives in South Jersey. We took my 4 week old daughter to the hospital for a fever of 100.9. They did a spinal tap and various blood tests and found that she had Babesia. Doctors believe that I was bitten by a tick during pregnancy. Doctors at that hospital had never seen Babesia in a newborn before, but they knew exactly how to treat it. They gave her antibiotics and she ended up needing two blood transfusions to treat her anemia. We spent a week in the hospital. When we left her parasite levels were below 1% and her hemoglobin was at a 9.5. Very terrifying experience for a new mother and father to go through, but she is the perfect little baby now at two months old.