Babesia pregnancy transmission is real and underrecognized. In this Inside Lyme case study, I discuss two mothers who unknowingly passed this tick-borne parasite to their babies.
Saetre and colleagues first described these cases in the Journal of the Pediatric Infectious Disease Society in 2017.
This parasite can be contracted from the bite of a deer tick, a blood transfusion, or during pregnancy. The CDC recognizes that transmission can occur in utero.
First Mother with Babesia Pregnancy
The first mother lived in Westchester County, New York, an area endemic for Lyme disease. I live and practice medicine in the same county.
The mother was diagnosed with Lyme disease in her third trimester at 32 weeks gestation. She presented with an erythema migrans rash (EM). She was treated with amoxicillin.
I advise mothers that neither amoxicillin nor azithromycin is effective against other common tick-borne infections such as Ehrlichia, Anaplasmosis, and Babesia.
The doctors followed the mother. She was positive by IgM laboratory testing two weeks after her diagnosis of Lyme disease. A positive IgM test would be consistent with an early infection. I would have treated the mother.
The mother was not treated. The mother and her baby boy went home.
The mother’s baby boy was diagnosed and treated 4½ weeks after going home.
The mother was again positive. The tests were now positive by an IgG western blot. The conversion from a positive IgM western blot test to a positive IgG western blot test was further evidence that the mother contracted this infection during her third trimester. I would still have treated the mother.
Again the mother was not treated—an example of how tick-borne infections get dismissed even with clear evidence.
Second Mother with Babesia Pregnancy
The second mother lived in Putnam County, New York, an area endemic for Lyme disease. Putnam County is located just north of Westchester County.
The mother initially had muscle soreness and a fever for two weeks. She was diagnosed with Lyme disease in her third trimester at 37 weeks gestation. She presented with an EM rash and was treated with amoxicillin.
The mother’s laboratory tests for a tick-borne infection were not positive at the time of her EM rash.
Her baby girl was tested after delivery. Her girl’s blood test was positive for Babesia microti by PCR. The doctors did not look for the parasite in her baby girl’s red blood cells under the microscope. The doctors concluded that the baby girl showed no symptoms. Her baby girl was not treated.
The mother and her baby girl went home.
Her baby girl had evidence of this parasite in her red blood cells when she was 18-days-old. Her girl was hospitalized and treated with a series of antibiotics, antiparasitic medications, and a blood transfusion.
The mother’s blood tests were now positive by PCR, IgM, and IgG tests. The conversion from a positive IgM to a positive IgG was further evidence that the mother contracted this infection during her third trimester.
The mother was not treated. The baby girl was.
What Babesia Pregnancy Cases Teach Us
- Women can contract this parasite during their pregnancy
- Pregnant women can transmit the infection to their babies in utero
- There can be a delay in the onset of symptoms after contracting Lyme disease—in these cases, the co-infection appeared weeks later
- Mothers with positive tests may go untreated while their babies are diagnosed weeks later
Treating Tick-Borne Disease in Pregnancy
We need more doctors with skills diagnosing and treating this infection in children and their mothers. We need to determine the best course of treatment for pregnant women and their children.
Babesia pregnancy transmission is preventable when doctors recognize the risk. Mothers with persistent symptoms after Lyme treatment should be evaluated for this co-infection—especially if symptoms appeared during pregnancy.
If you’re pregnant and have been bitten by a tick or diagnosed with Lyme disease, ask your doctor about screening—it could protect you and your baby.
Frequently Asked Questions
Can Babesia be passed from mother to baby during pregnancy?
Yes. Babesia pregnancy transmission can occur in utero. Both mothers in this case passed the infection to their babies during the third trimester.
Does treating Lyme disease treat Babesia too?
No. Amoxicillin and doxycycline treat Lyme disease but are not effective against Babesia, which requires different medications like atovaquone and azithromycin.
Should pregnant women with Lyme disease be tested for Babesia?
Yes. Pregnant women diagnosed with Lyme disease should be tested for co-infections including Babesia, especially if they live in or traveled to endemic areas.
Why weren’t the mothers treated?
Despite positive test results, both mothers were left untreated—an example of how babesia pregnancy cases can be dismissed even with clear laboratory evidence.
What happened to the babies?
Both babies were eventually diagnosed and treated, but not until weeks after going home. One baby required hospitalization and a blood transfusion at 18 days old.
References
- Saetre K, Godhwani N, Maria M, et al. Congenital Babesiosis After Maternal Infection With Borrelia burgdorferi and Babesia microti. J Pediatric Infect Dis Soc. 2017.
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.