If you are pregnant and have toxoplasmosis, there is a risk of the infection passing through the placenta to your baby. Your doctor may perform special procedures that test for fetal infection.

Your doctor may perform an amniocentesis, which tests the amniotic fluid (fluid from the sac that holds your baby in the womb) for the presence of parasitic DNA, which could only be present if the fetus or placenta is infected.. In rare cases where serology and amniocentesis are unable to secure a diagnosis, a procedure called umbilical cord blood sampling may be performed to test fetal blood for the presence of parasitic DNA.

Additional tests may help determine if toxoplasmosis has infected your baby’s liver or blood cells or to see if your baby’s immune system has begun producing antibodies against toxoplasma. If these tests are normal, it is unlikely that your baby is infected.

If your baby is infected during the first or second trimester of pregnancy, an ultrasound examination may show abnormalities, such as enlargement of fluid-filled areas in the brain (ventriculomegaly), calcium deposits in the brain (intracranial calcifications), enlargement of the liver or spleen (hepatomegaly and splenomegaly), or fluid in the abdomen (ascites).

Unfortunately, these disorders are sometimes seen in babies with problems other than toxoplasma infection. Further, most babies infected with toxoplasma do not develop these abnormalities. If an ultrasound shows any of the abnormalities listed above, your doctor should perform additional tests to determine whether or not they are a result of toxoplasmosis. It is important to know that, if your baby does have toxoplasmosis, neither ultrasound nor blood tests can accurately predict how serious the infection is or what, if any, consequences your baby will have in the future.