Lyme Disease in Pregnancy

Key messages for health care providers

  • Black-legged or deer ticks (BLT) are found throughout Nova Scotia. Preventing a BLT bite is the most effective way to prevent Lyme disease. Risk reduction strategies include using DEET-containing insect repellant (safe to use in pregnancy) and careful ‘tick checks’ after being in grassy or wooded areas, including a park or yard. Immediate and correct removal of an attached BLT is key to prevention. For advice about tick removal see:
  • Prophylaxis may be considered. A single 200 mg dose of doxycycline, which is not contraindicated for pregnant women, may be offered if all of the following criteria are met.
    • BLT attached for > 24 hours, AND
    • antibiotic prophylaxis is given < 72 hours from tick removal, AND
    • the bite occurred in an area considered at higher or moderate risk for Lyme disease, which is most of NS. For risk level by NS County see map at this link:
  • The risk of Lyme disease after a bite from an infected BLT is low (1.2%-3.2%). However, if a bite occurs advise observation for signs and symptoms for 30 days, even if there has been prophylaxis.
  • Think about Lyme disease in your differential for a patient presenting with new onset febrile illness, especially when associated with a localized skin lesion. Early infection is a clinical diagnosis.  The sensitivity of two-tiered serologic testing, the recommended testing standard in Canada and the US, is < 50% in early, localized Lyme disease. The test performs well in early disseminated and in late Lyme disease. For information about testing see:
  • Treatment for pregnant women with Lyme disease is similar to treatment for the general adult population, with the exception that treatment doses of doxycycline are contraindicated in pregnancy. With 10-28 days of oral antibiotic treatment, 95% of cases of Lyme disease are resolved. For treatment recommendations see:
  • There is not enough evidence to confirm that Lyme disease during pregnancy has adverse effects for the fetus. In addition, no adverse effects for the fetus have been observed when the pregnant woman receives appropriate antibiotic treatment for her Lyme disease.

For more information about Lyme disease, refer to the following resources:

From the Government of Canada and the Public Health Agency of Canada

From the Nova Scotia Department of Health & Wellness

Date Revised: 
June, 2019