What is the recommended treatment for toxoplasmosis during pregnancy?

Treatment of Toxoplasmosis During Pregnancy

For pregnant women with active toxoplasmosis, the recommended treatment depends on timing of infection, with spiramycin used before 18 weeks gestation and pyrimethamine/sulfadiazine/folinic acid used after 18 weeks or when fetal infection is confirmed. 1

Treatment Algorithm Based on Gestational Age and Infection Status

For Suspected or Confirmed Infection Before 18 Weeks Gestation

• Spiramycin is the first-line treatment (1g or 3 million IU orally three times daily) 1
• Spiramycin is not teratogenic and should be continued until delivery if amniotic fluid PCR is negative and ultrasound findings remain normal 1
• In the United States, spiramycin is available only through the FDA's Investigational New Drug process 1

For Suspected or Confirmed Infection At or After 18 Weeks Gestation

• Pyrimethamine plus sulfadiazine plus folinic acid is recommended when:
  • Infection is acquired at or after 18 weeks gestation 1
  • Amniotic fluid PCR is positive for T. gondii 1
  • Abnormal fetal ultrasound findings suggestive of congenital toxoplasmosis are present 1

For Confirmed Fetal Infection (Any Gestational Age)

• Switch from spiramycin to pyrimethamine/sulfadiazine/folinic acid combination therapy 1, 2
• Folinic acid (leucovorin) must be administered concurrently with pyrimethamine to prevent bone marrow suppression 3

Important Considerations and Monitoring

Teratogenicity Concerns

• Pyrimethamine is classified as Pregnancy Category C due to teratogenic effects in animal studies 3
• Women taking pyrimethamine should be warned against becoming pregnant 3
• When used for treatment of confirmed toxoplasmosis during pregnancy, the benefit justifies the potential risk 3

Laboratory Monitoring

• For patients receiving high doses of pyrimethamine, semiweekly blood counts including platelet counts should be performed 3
• Monitor for signs of folate deficiency; if present, pyrimethamine should be discontinued 3

Consultation Requirements

• Each case involving a pregnant woman with suspected acute toxoplasmosis should be discussed with an expert in toxoplasmosis management 2
• Pregnant women with evidence of primary infection or active toxoplasmosis should be evaluated in consultation with appropriate specialists 1

Special Situations

For HIV-Infected Pregnant Women

• TMP-SMZ can be administered for prophylaxis against toxoplasmosis encephalitis 1
• Women who are immunosuppressed or HIV-positive should be offered screening due to risk of reactivation 2

For Women with Previous Toxoplasma Infection

• Anti-toxoplasma treatment in immunocompetent pregnant women with previous infection is not necessary 2
• For women with history of toxoplasmosis who are now immunosuppressed, prophylaxis may be required 1

Post-Infection Family Planning

• Non-pregnant women diagnosed with acute toxoplasmosis should wait 6 months before attempting pregnancy 2

Prevention Strategies

• Educate pregnant women about toxoplasmosis transmission routes: undercooked meat, cat feces, contaminated soil/water 4, 5
• Advise thorough cooking of meat to safe temperatures 4
• Recommend peeling or washing fruits and vegetables before consumption 4
• Suggest wearing gloves when gardening or changing cat litter 4, 5
• Avoid feeding raw meat to cats and keep them indoors 4

Diagnostic Approach

• Suspected recent infection should be confirmed at a toxoplasmosis reference laboratory 2
• If acute infection is suspected, repeat testing should be performed within 2-3 weeks 2
• Amniocentesis should be offered after 18 weeks' gestation and at least 4 weeks after suspected maternal infection to identify T. gondii by PCR 2
• Infants born to women with serologic evidence of toxoplasmosis should be evaluated for congenital infection 1