Congenital toxoplasmosis is a disease that occurs in fetuses infected with Toxoplasma gondii, a protozoan parasite, which is transmitted from mother to fetus. It can cause miscarriage or stillbirth. It can also cause serious and progressive visual, hearing, motor, cognitive, and other problems in a child.

There are approximately 400 to 4,000 cases of congenital toxoplasmosis each year in the United States.

Symptoms and Complications of Congenital Toxoplasmosis

Most infected infants appear healthy at birth. They often do not develop symptoms until months, years, or even decades later in life.

Infants with severe congenital toxoplasmosis usually have symptoms at birth or develop symptoms within the first six months of life.

Symptoms may include:

  • premature birth — as many as half of infants with congenital toxoplasmosis are born prematurely
  • abnormally low birth weight
  • eye damage
  • jaundice, yellowing of the skin and whites of the eyes
  • diarrhea
  • vomiting
  • anemia
  • difficulty feeding
  • swollen lymph nodes
  • enlarged liver and spleen
  • macrocephaly, an abnormally large head
  • microcephaly, an abnormally small head
  • skin rash
  • vision problems
  • hearing loss
  • motor and developmental delays
  • hydrocephalus, a buildup of fluid in the skull
  • intracranial calcifications, evidence of areas of damage to the brain caused by the parasites
  • seizures
  • mild to severe mental retardation

What Are the Risks of My Unborn Child Getting Congenital Toxoplasmosis?

If you become infected with the parasites during your first trimester of pregnancy, your baby has a 15-20 percent chance of getting congenital toxoplasmosis. However, if you become infected during your third trimester, your unborn child has about a 60 percent chance of becoming infected, according to estimates from the Boston Children’s Hospital.

What Causes Congenital Toxoplasmosis?

You can get the T. gondii parasites in several ways:

  • by eating uncooked or undercooked meat
  • from unwashed produce
  • by drinking water that is contaminated with the parasites or their eggs, though it is rare to get the parasites from water in the United States
  • by touching contaminated soil or cat feces and then touching your mouth

If you become infected with the parasites during your pregnancy, you can pass them to your unborn child during pregnancy or delivery.

Should I Get Rid of My Cat?

You can keep your cat, even if they have the parasites. The risk of getting the parasites from your cat is very low, according to the Centers for Disease Control and Prevention. However, make sure to have someone else change your cat’s litter box for the entire duration of your pregnancy.

How Is It Diagnosed?

Your doctor may perform a blood test to detect the parasites. If you test positive for the parasites, they may perform the additional tests during your pregnancy to determine if your unborn baby is also infected. These tests include:

  • ultrasound to check for fetal abnormalities, such as hydrocephalus
  • polymerase chain reaction, or PCR, amniotic fluid testing, although this test may produce false negative or false positive results
  • fetal blood testing

If your baby shows symptoms of congenital toxoplasmosis after birth, your doctor may perform one or more of the following tests:

  • antibody test on the umbilical cord blood
  • antibody test on your baby’s cerebrospinal fluid
  • blood test
  • eye exam
  • neurological exam
  • CT or MRI scan of your baby’s brain

How Is It Treated?

Some form of medication is typically used to treat congenital toxoplasmosis:

Medications Given During Pregnancy

  • spiramycin, or Rovamycine, to help prevent the transmission of parasites from you to your fetus
  • pyrimethamine, or Daraprim, and sulfadiazine may be given to you after the first trimester if it has been confirmed that your fetus is infected with the parasites
  • folic acid to protect from bone marrow loss in you and your fetus, caused by pyrimethamine and sulfadiazine
  • pyrimethamine, sulfadiazine, and folic acid, usually taken for one year
  • steroids if your baby’s vision is threatened or if your baby has high protein levels in their spinal fluid

Medications Given to a Baby After Birth

In addition to medication, your doctor may prescribe other treatments, depending on your baby’s symptoms.

Long-Term Expectations

Your baby’s long-term outlook depends on the severity of their symptoms. The parasite infection generally causes more serious health problems to fetuses that contract it in early pregnancy rather than late pregnancy. If detected early, medications can be given before the parasites harm your fetus. Up to 80 percent of infants with congenital toxoplasmosis will develop visual and learning disabilities later in their lives. Some infants may experience vision loss and lesions in their eyes thirty or more years after birth.


Congenital toxoplasmosis in the United States can be prevented if you, as an expecting mother:

  • cook food thoroughly
  • wash and peel all fruits and vegetables
  • wash your hands frequently and any cutting boards used to prepare meat, fruits or vegetables
  • wear gloves when gardening or avoid gardening altogether to avoid contact with soil that may contain cat waste
  • avoid changing the litter box

Following these simple guidelines will help you avoid getting infected by the parasites that cause toxoplasmosis and therefore can’t pass them onto your unborn child.