Approach to toxoplasmosis in pregnancy

PCR: polymerase chain reaction; T. gondii: Toxoplasma gondii.
* Routine screening is not performed in all countries. Where screening is performed, frequency of screening during pregnancy varies among protocols. A discussion of serologic diagnosis can be found in the UpToDate content on diagnostic testing for toxoplasmosis infection.
¶ Patients who begin spiramycin before 14 weeks can continue this drug until PCR results from the amniocentesis at 18 weeks are available to guide further treatment decisions; alternatively, they may switch to pyrimethamine-sulfadiazine at 14 weeks and continue pyrimethamine-sulfadiazine until PCR results from the amniocentesis at 18 weeks are available. Refer to UpToDate content on toxoplasmosis in pregnancy for a detailed discussion.
Δ When possible, amniocentesis at ≥18 weeks is timed to be at least 2 weeks after documentation of seroconversion (or 4 weeks after the estimated date of maternal primary infection) to improve diagnostic performance.
◊ Counsel the patient on the likelihood of congenital defects. Most cases are not severe enough to warrant pregnancy termination; however, patients consider multiple personal factors in making this decision.
§ The appearance of fetal lesions suggestive of infection on ultrasound following a negative PCR is rare. Nevertheless, because of the rare residual risk of congenital toxoplasmosis after a primary infection despite a negative amniocentesis, ultrasound follow-up is suggested every 4 to 6 weeks.