In every pregnancy, a woman starts out with a 3-5% chance of having a baby with a birth defect. This is called her background risk. This sheet talks about whether toxoplasmosis may increase the risk for birth defects over that background risk. This information should not take the place of medical care and advice from your health care provider.

What is toxoplasmosis?

Toxoplasmosis is an infection caused by the parasite Toxoplasma gondii. You can get it by eating infected meat that hasn’t been cooked properly, drinking water that is contaminated, or handling soil or cat feces that contain the parasite. Although most adults have no symptoms if infected, some people might have swelling of the lymph nodes, fever, headache or muscle pain (flu like symptoms). In most cases, once you have gotten toxoplasmosis, you cannot get it again.

How can I find out if I am at risk for toxoplasmosis?

Around 65% to 85% of pregnant women in the United States are at risk for toxoplasmosis infection. Women who have recently gotten a cat or have outdoor cats, eat undercooked meat, garden, or who have had a recent mononucleosis-type illness are at increased risk.

A blood test can determine if you have ever had toxoplasmosis. Ideally, testing for toxoplasmosis should be done before getting pregnant. If an infection is identified during pregnancy, more than one test may be needed to see whether the infection is recent or old. Talk with your health care provider if you have concerns and want to learn about testing.

What precautions can I take to avoid infection?

Toxoplasma gondii can be found in raw or undercooked meat, raw eggs and unpasteurized milk. Cats that eat raw meat or rodents can become infected. Once infected, the cat can shed the parasite in the feces for up to two weeks. Toxoplasma gondii eggs can live in cat feces buried in soil up to 18 months. To avoid infection, pregnant women should:

  • Cook meat until it is no longer pink and the juices run clear. A food thermometer should be used to measure the internal temperature of cooked meat to make sure the meat is cooked all the way through.
  • Wash cutting boards, dishes, counters and utensils with hot soapy water after any contact with raw meat, seafood, or unwashed fruits or vegetables.
  • Wash hands carefully after handling raw meat fruit, vegetables, and soil.
  • Wash all fruits and vegetables. Peeling fruits and vegetables also helps to reduce risk of exposure.
  • Do not touch cat feces or wear gloves if changing cat liter & immediately wash hands.
  • Do not feed cats raw meat.

I had a toxoplasmosis infection two years ago and I am currently pregnant. Is my baby at risk?

Infection of the developing baby only occurs when the mother has an active infection during pregnancy. In general, there is no increased risk to the baby when toxoplasmosis occurs more than 6 months prior to conception. If you had toxoplasmosis in the past, you are likely immune, which means that the baby would not be at risk. If you have a weakened immune system, such as in AIDS, you can develop another active infection.

I am pregnant and I have recently been infected with toxoplasmosis. Is my baby at risk?

The toxoplasmosis parasite is known to cross the placenta. In about 20 percent of the cases in which a pregnant woman has toxoplasmosis, the baby is also infected. Infants who become infected during pregnancy are said to have “congenital toxoplasmosis” infection. In the United Sates, between 400 and 4000 babies are born with toxoplasmosis each year. Some infants with congenital toxoplasmosis will have medical conditions that include problems with the brain, eyes, heart, kidneys, blood, liver, or spleen. Long-term effects may include seizures, mental retardation, cerebral palsy, deafness, and blindness. Many infected infants will have no problems at birth, but should be followed by their health care provider for several years after birth as complications do not always start at birth. Miscarriage or stillbirth have also been reported.

When the mother is infected during the first trimester, the risk that the baby will be infected is 10-15%. This is also the time in gestation when the baby is at a higher risk for severe problems from infection. When the mother is infected late in pregnancy, the chance that the baby will have severe problems is very small.

If my baby is born without any symptoms of congenital toxoplasmosis, does this mean the toxoplasmosis infection in pregnancy had no effect?

Infants with congenital toxoplasmosis usually don’t appear any different at birth. Yet, long-term studies show that up to 90 percent develop problems including vision loss, hearing loss, or developmental delays. These symptoms can occur months or even several years after birth. For this reason, infants with congenital toxoplasmosis should be treated for the infection during the first year of life and then should be periodically checked for problems.

How can I find out if my baby has been infected with toxoplasmosis?

If you have recently been infected, the fluid around the baby or fetal blood can be tested for the infection during pregnancy. However, if the baby is infected, these tests cannot tell you how severe the infection is. About one-third of babies with congenital toxoplasmosis will have a problem that can be seen on ultrasound. After birth, a blood test can be performed on the baby to determine if the baby is infected.

Is there any treatment for toxoplasmosis during pregnancy?

Maternal toxoplasmosis infection can be treated. Early identification and treatment can reduce the chance that the baby will become infected. If the baby has already become infected, treatment with other medications might make the baby’s disease less severe. Your health care provider can discuss specific treatment options with you.

If I have had toxoplasmosis in the past, should I avoid breastfeeding my baby?

No. Breastfeeding provides the baby with nutritional and health benefits. Since most women with a history of toxoplasmosis will build immunity to the parasite, it is unlikely that toxoplasmosis will be passed through breast milk. Talk to your health care provider about all your breastfeeding questions.

Should I be concerned if the father of my baby has toxoplasmosis while I am pregnant or breastfeeding?

No. A father cannot pass toxoplasmosis to you or the baby. For general information on exposures that fathers have, please see the MotherToBaby fact sheet on Paternal Exposures at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/pdf/.

References Available By Request