ACOG Guidelines at a Glance: Key points about 4 perinatal infections
Congenital toxoplasmosis occurs in 25% to 50% cases, with higher rates in later gestation. Toxoplasmosis-specific IgM appears shortly after infection and once IgG titers appear, the patient is immune. However, the titers have high rates of false-positive and -negative results. If both IgG and IgM are positive, the infection may be acute and serologic testing should be repeated in 2 to 3 weeks. If IgG is increased, the infection is most likely acute. An experienced laboratory should be used for these assays.
1. Avidity testing can also be used for toxoplasmosis and low avidity is consistent with a primary infection within 5 months.
2. If fetal infection is suspected (eg, primary maternal infection plus fetal findings such as ventriculomegaly, intracranial calcifications, microcephaly, ascites, hepatosplenomegaly, and growth restriction), amniocentesis should be done after 18 weeks and PCR performed on amniotic fluid to test for toxoplasmosis DNA. The recommendation in 2000 was to proceed to fetal blood sampling for diagnosis.
3. Routine serologic testing for toxoplasmosis is not recommended in pregnancy.
Level A recommendations
1. Pregnant women acutely infected with toxoplasmosis should be treated with spiramycin to reduce transplacental transmission. (However, this drug is difficult to get and requires assistance from the FDA because it is not readily available in the United States [CDC 2015].6)
2. Fetal infection with toxoplasmosis should be treated with pyrimethamine, sulfadiazine, and folinic acid because this regimen better eradicates parasites in a fetus and placenta than does spiramycin alone and it can lessen the severity of fetal disease.