Syphilis Treatment in Pregnancy

Syphilis during pregnancy can cause risks to both you and your baby. If you are not treated for syphilis during your pregnancy, it can harm your baby and may lead to your baby being born with syphilis (congenital syphilis). Getting tested for syphilis when you are pregnant and getting treated early if your test is positive can lower these risks.

Treatment for syphilis during pregnancy

Long-acting penicillin, given with a needle, is the most effective treatment for syphilis when you’re pregnant.
Getting treated when you’re pregnant lowers the risk of your baby:

• getting syphilis
• being born too early
• dying before or shortly after birth

Early treatment with antibiotics can prevent these risks for both you and your baby.
Talk to your healthcare provider about the right treatment for you if you’re allergic to penicillin.

Jarisch-Herxheimer reaction

The Jarisch-Herxheimer (JH) reaction can happen after being treated for syphilis with penicillin. This reaction can happen in about 4 out of 10 pregnant people who are treated. Symptoms usually will go away within 24 hours.
Symptoms may begin 2 to 12 hours after treatment and may include:

• fever
• feeling very tired
• sweating
• headache
• joint pain
• fast heartbeat

There is no speci?c treatment for the JH reaction. Rest, drinking enough water, and pain medication may help. Always check with your healthcare provider or pharmacist before taking any medicines during pregnancy.

Does my baby need extra care?

While the reaction can be uncomfortable, the risk to your baby from a JH reaction is lower than the risk of not treating syphilis. However, you may start to have contractions, go into early labour, or your baby’s movements or heart rate may change. Get medical help right away if this happens.

Your healthcare provider may recommend fetal monitoring for 24 hours after you’re treated for syphilis. Fetal monitoring is a process where healthcare providers track your baby’s heart rate and your contractions. This can help identify any signs of distress in your baby or other issues.

Monitoring is not always needed after treatment. It may be recommended for some people, for example if your ultrasound shows signs of syphilis in your baby.

What should I do if I have a JH reaction?

Call your doctor or Health Link
If you have the following symptoms after being treated for syphilis, call your healthcare provider or Health Link at 811. These include if you have:

• a fever
• a feeling of being very tired
• any sweating
• a headache
• joint pain
• a fast heartbeat

Get immediate medical attention

Call your healthcare provider or go to your nearest hospital right away if:

• you think you are in early labor
• your baby is not moving as much as usual

To see this information online and learn more, visit MyHealth.Alberta.ca/health/aftercareinformation/pages/conditions.aspx?hwid=custom.ab_syphilis_treatment_pregnancy_inst.

For 24/7 nurse advice and general health information call Health Link at 811.

Current as of: April 09, 2025
Author: Provincial STI Programs, Alberta Health Services
This material is not a substitute for the advice of a qualified health professional. This material is intended for general information only and is provided on an "as is", "where is" basis. Although reasonable efforts were made to confirm the accuracy of the information, Alberta Health Services does not make any representation or warranty, express, implied or statutory, as to the accuracy, reliability, completeness, applicability or fitness for a particular purpose of such information. Alberta Health Services expressly disclaims all liability for the use of these materials, and for any claims, actions, demands or suits arising from such use.