Toxoplasmosis is an infection caused by a parasite called Toxoplasma gondii. The Toxoplasma parasite can live in cat feces (poop), water, soil, or certain foods. Exposure to Toxoplasma is common, and in most children and adults, a Toxoplasma infection is harmless.

Congenital toxoplasmosis happens when a pregnant mother infected with Toxoplasma passes the parasite to the baby during pregnancy.

Signs and symptoms can be mild or severe and may appear right away or can develop later.

• Most babies infected with Toxoplasma before birth will not have any health problems right away, but often develop signs and symptoms later in life.
• Some babies who are infected with Toxoplasma will be born with health problems. Babies may be born too early or have damage to the brain, eyes, and other organs.
• Typically, babies infected with Toxoplasma earlier in pregnancy (in the first trimester) have more severe health problems than those infected later in pregnancy.

Pregnant women can pass Toxoplasma to their unborn baby. This usually happens when a mother becomes infected with toxoplasmosis during pregnancy and the parasite crosses the placenta and infects the baby. Some mothers who have problems with their immune system can also pass Toxoplasma to their unborn baby if they had a Toxoplasma infection before they became pregnant.

The chance of the baby getting toxoplasmosis from the mother depends on when the infection happens in the pregnancy. In the first trimester, the chance of the baby getting infected is about 25%. In the second trimester, the chance goes up to about 50%, and the chance is highest in the third trimester, at about 65%. If a woman is found to have toxoplasmosis during pregnancy, treatment of the mother may decrease the chance that the baby will become infected.

About 1 of every 10 babies with toxoplasmosis will have signs and symptoms at birth. Most babies with toxoplasmosis who appear healthy at birth will develop signs and symptoms later in childhood or as adults.

Signs of the condition that may be present at birth or may develop later in life include the following:

• Eye and vision problems (chorioretinitis)
• Fluid in the brain (hydrocephalus)
• Build-up of calcium in the brain (intracranial calcifications)
• Unusually large or small head (macrocephaly or microcephaly)
• Bruising or rash
• Yellow skin or eyes (jaundice)
• Large liver or spleen (hepatosplenomegaly)
• Seizures
• Hearing loss
• Developmental delay

Newborn screening for Congenital toxoplasmosis requires collecting a small amount of blood from your baby’s heel. Screening measures whether your baby is making antibodies to Toxoplasma. Antibodies are special proteins the body’s immune system makes when it has been infected.

What Happens After an Out-of-Range Screening Result?

If your baby’s toxoplasmosis screen is positive, your baby’s health care provider will contact you. Together, you will discuss next steps and follow-up plans.

A positive toxoplasmosis screening result does not mean that your baby will have or develop health problems. It does mean that your baby needs follow-up testing.

Your baby may need the following tests after a positive toxoplasmosis screening result:

• Blood tests
• Eye exams

You should complete any recommended follow-up testing as soon as possible. Babies with this condition may develop health problems if they are not diagnosed and treated.

False-positive and false-negative screening results for Congenital toxoplasmosis can and do happen.

Newborn screening helps babies lead healthier lives. If your baby has a positive Toxoplasma screening result, follow up with your health care provider quickly. It is important to follow their instructions. Your baby may need treatment, even if he or she is not showing any signs or symptoms. In some cases, your baby’s health care provider may decide it is best to watch (monitor) your baby to decide next steps. Careful monitoring and early treatment will help your baby stay as healthy as possible.

Babies with a Congenital toxoplasmosis infection will need treatment to prevent some of the health problems caused by this condition. Talk to your health care provider about when to start treatment and which treatment(s) are best for your baby.

Treatment options can include the following:

• Medications (pyrimethamine, sulfadiazine, and leucovorin)
• Regular hearing tests to check for hearing loss
• Regular vision tests to check for vision loss
• Steroids

Congenital toxoplasmosis is not inherited through a person’s genes, so usually other family members do not have a higher chance of Congenital toxoplasmosis.

There are a number of ways you can reduce your chance of getting toxoplasmosis. This is especially important when you are pregnant:

• Avoid cleaning out cat litter boxes or coming into contact with cat feces (poop) or stray cats
• Wear gloves when gardening or during any contact with soil or sand
• Do not eat raw or undercooked pork, beef, lamb, mutton, or wild game meat
• Do not eat unwashed vegetables or fruits
• Do not drink raw (unpasteurized) milk
• Wash your hands and kitchen utensils regularly