What is the treatment for Borrelia (B.) burgdorferi infection in a pregnant patient?

From the Guidelines

For pregnant patients with Borrelia burgdorferi infection (Lyme disease), the recommended treatment is amoxicillin 500 mg three times daily for 14-21 days. This is the first-line therapy due to its proven safety profile during pregnancy, as noted in the guidelines by the Infectious Diseases Society of America 1. Alternatively, if the patient has a penicillin allergy, cefuroxime axetil 500 mg twice daily for 14-21 days can be used, as suggested in the clinical practice guidelines 2. Doxycycline, which is typically used in non-pregnant adults, should be avoided during pregnancy due to potential adverse effects on fetal bone and teeth development.

The key considerations for treating Lyme disease in pregnant patients include:

• The stage and severity of the infection, which determines the duration of treatment, with early localized disease requiring 14 days and more disseminated disease needing 21 days 2.
• The safety profile of the antibiotic, with amoxicillin being preferred over doxycycline due to its safety during pregnancy 1.
• The potential for complications, such as placental infection and adverse pregnancy outcomes, if the disease is left untreated 1.

Close monitoring during and after treatment is essential, with follow-up evaluations to ensure resolution of symptoms. The antibiotics work by inhibiting bacterial cell wall synthesis, effectively eliminating the spirochete bacteria before it can cause more serious systemic complications. It's also important to note that while there is limited evidence on the use of amoxicillin for prophylaxis after a tick bite in pregnant women, some practitioners prescribe a 10–14-day course of prophylactic amoxicillin for pregnant women after I. scapularis tick bites, due to concerns about adverse outcomes for the fetus if Lyme disease develops 1. However, the guidelines emphasize that favorable outcomes can be expected when pregnant women with Lyme disease are treated with standard antibiotic regimens 1.

From the FDA Drug Label

Pregnancy Teratogenic Effects Reproductive studies have been performed in mice and rats at doses up to 20 times the usual human dose and have no evidence of embryotoxicity, fetotoxicity or teratogenicity. In primates, no embryotoxicity or teratogenicity was demonstrated at a dose approximately 3 times the human dose. There are, however, no adequate and well-controlled studies in pregnant women Because animal reproductive studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed

The treatment of B. burgdorferi in a pregnant patient with ceftriaxone should be done with caution, as there are no adequate and well-controlled studies in pregnant women.

• Ceftriaxone should only be used during pregnancy if clearly needed. 3

From the Research

Treatment of B. burgdorferi in Pregnant Patients

There are no specific studies provided that directly address the treatment of B. burgdorferi in pregnant patients. However, we can look at the general effectiveness of various antibiotics against B. burgdorferi:

• The study 4 found that ceftriaxone, cefuroxime sodium, azithromycin, amoxicillin, and doxycycline were effective against B. burgdorferi, with cefuroxime sodium, azithromycin, and ceftriaxone displaying the lowest minimum inhibitory concentrations (MICs).
• The study 5 identified vancomycin as an effective antibiotic for killing B. burgdorferi, and found that it was more effective than ceftriaxone in killing the pathogen in vitro.
• The study 6 examined the kill kinetics of B. burgdorferi under various antibiotics, including amoxicillin, doxycycline, cefotaxime, ceftriaxone, azithromycin, and penicillin G, and found that the killing rate of a given antibiotic is less dependent on the concentration of the antibiotic than on the reaction time.

Antibiotic Options

Some potential antibiotic options for treating B. burgdorferi include:

• Ceftriaxone 4, 5
• Cefuroxime sodium 4
• Azithromycin 4
• Amoxicillin 4, 6
• Doxycycline 4, 6
• Vancomycin 5

Considerations for Pregnant Patients

When considering treatment options for pregnant patients, it is essential to weigh the potential risks and benefits of each antibiotic. However, without specific studies on the treatment of B. burgdorferi in pregnant patients, it is challenging to provide definitive guidance.