Primary syphilis
ICD-10 A51.0 · ICD-11 1A61.0

Treatment of Primary Syphilis in Pregnancy

Clinical Scenario

Primary syphilis diagnosed in a pregnant patient requires prompt, evidence-based management to protect both the mother and the developing fetus. The trimester of diagnosis is a clinically relevant factor in determining the treatment approach.

Pregnancy Context

All pregnant women and people should have serological screening for syphilis as part of their first antenatal assessment. When primary syphilis is identified, the gestational timing of treatment initiation — particularly whether therapy begins in the third trimester — shapes the clinical decisions that follow.

Treatment Approach (Partial Overview)

In the absence of penicillin allergy, treatment centres on benzathine penicillin G. The specific regimen — including whether a second dose is warranted based on gestational timing and fetal assessment findings — is defined in the full structured protocol.

Dosing details, route, interval, and trimester-specific modifications are in the full protocol below.

Treatment Goal

The primary serological target after treatment is a four-fold drop in the quantitative RPR (non-treponemal) titre. It may take several months to observe this response, and in many pregnancies delivery will occur beforehand — making careful neonatal assessment an important part of follow-up planning.

Instant Access to Structured Evidence-Based Regimens

References

  1. All pregnant women and people should have serological screening for syphilis as part of their first antenatal assessment.
  2. In the absence of allergy to penicillin, standard benzathine penicillin G treatment should be given.
  3. Limited evidence suggests that a second dose of benzathine penicillin G 1 week after the first may be beneficial for fetal treatment in pregnant women or people with early syphilis, and in pregnancies with sonographic signs of fetal or placental syphilis as this indicates a greater risk of fetal treatment failure.
  4. For these reasons, when treatment for early syphilis is initiated in the third trimester, a second dose of benzathine penicillin G is recommended 1 week after the first, with careful assessment of the neonate at birth.
  5. It may take several months to observe a 4-fold drop in RPR titre and in many pregnancies delivery will occur beforehand.
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