Toxoplasmosis during pregnancy

What is toxoplasmosis?

Toxoplasmosis is an infection you can get from a microscopic parasite called Toxoplasma gondii. Although the infection generally causes a mild, symptomless illness in people with healthy immune systems, it's risky if you become infected just before or during pregnancy because the parasite may infect the placenta and your unborn baby.

This infection can be mild or severe, causing stillbirth, long-term structural and neurological damage, and other devastating effects. The good news is there's a lot you can do to avoid becoming infected in the first place.

How common is toxoplasmosis in pregnancy?

Fortunately, the number of women who contract the infection during pregnancy is relatively small, and not all of them transmit it to their babies. Researchers estimate that of the over 4 million births in the United States each year, between 300 and 4,000 babies are born with toxoplasmosis (known as congenital toxoplasmosis).

If you had toxoplasmosis in the past, you won't get it again, and your baby will be protected by your immunity. (But only about 15 percent of women of childbearing age are immune to toxoplasmosis, according to the Centers for Disease Control and Prevention.)

Your baby's risk of becoming infected rises as your pregnancy progresses. If you get infected with toxoplasmosis in the first trimester, the risk that your baby will also be infected is about 15 percent. If you get infected in the second trimester, your baby's risk is about 30 percent, and it's 60 percent in the third trimester. However, while the transmission rate is higher in late pregnancy, toxoplasmosis is more likely to be severe for your baby if they become infected in the first trimester.

There's also a very small risk of infecting your baby if you contract the infection within a few months before becoming pregnant. If you know that you've been infected recently, some experts suggest waiting for six months before trying to conceive.

How is toxoplasmosis spread?

You can get the parasite by:

• Eating raw or undercooked infected meat (Experts estimate that about half of toxoplasmosis infections are caused this way.)
• Eating unwashed contaminated produce
• Drinking contaminated water
• Handling contaminated soil, cat litter, or meat and then touching your mouth, nose, or eyes

Toxoplasmosis can't be transmitted from person to person, with the exception of transmission from mother to baby during pregnancy or from an infected blood transfusion or organ transplant.

How to prevent toxoplasmosis during pregnancy

Here are some guidelines to keep in mind:

• Cook meat well. This is the only way to be certain you've eliminated toxoplasmosis. Use a food thermometer to test the internal temperature of meat. Most meat should be cooked to a temperature of 160 degrees Fahrenheit, or 180 degrees F in the thigh for whole poultry. It's best to use a thermometer, but if you're doing without, cook the meat until it's no longer pink in the middle and the juices run clear. Be sure not to sample meat you're cooking before it's done.
• Don't drink unpasteurized juice or milk or products made from unpasteurized milk (like some cheese and yogurt).
• Avoid raw eggs and raw or undercooked oysters, mussels, or clams.
• Wash or peel fruits and vegetables before eating.
• Wash counters, cutting boards, dishes, utensils, and your hands with hot, soapy water after working with unwashed produce or uncooked meat, poultry, or seafood.
• Don't touch your mouth, nose, or eyes while preparing food, and always wash your hands before eating. Also make sure cuts and open sores aren't in contact with potential sources of exposure to the parasite. Wear disposable gloves if you have any cuts on your hands.
• Keep flies and cockroaches away from your food.
• Avoid potentially contaminated water. Use bottled water when camping or traveling in developing countries.
• Wear gloves while gardening, and don't touch your hands to your mouth, nose, or eyes until they've been washed thoroughly afterward.
• Avoid public sandboxes, and cover your child's sandbox when it's not in use. If that's not always possible, then stay out of it. (Toxoplasmosis isn't likely to be harmful to your child and you can't catch it from him if he does get it, but you do need to stay away from sand that might contain infected cat feces.)

If you live with a cat:

• Have other people empty the litter box, and have them do it daily. If you must do the job, wear disposable gloves and wash your hands well afterward. Some experts also suggest wearing a mask in case any particles become airborne when the litter is stirred up.
• To keep your cat from becoming infected while you're pregnant, feed him only commercial cat food or well-cooked table scraps - never raw or undercooked meat.
• Keep him indoors so he won't hunt down potentially infected prey like mice or birds. (Remember, though, that even an indoor cat might catch a mouse.)
• Keep your kitty off the kitchen counter and dining table.
• Though it's unlikely your cat has any parasites in his fur, it's a good idea to wash your hands after playing with him, especially before eating or otherwise putting your hands to your mouth.
• Don't get a new kitten or cat while you're pregnant, and don't play with stray cats or kittens.

Signs and symptoms of toxoplasmosis

The vast majority of infected people with healthy immune systems don't have any symptoms at all. If you do, you may have painless swollen lymph glands and other generally mild symptoms, like muscle aches, fatigue, headache, fever, and possibly a sore throat or a rash. Without testing, you probably won't know you've been infected.

Only rarely do more serious symptoms arise in otherwise healthy people. Sometimes toxoplasmosis is suspected when certain fetal abnormalities are picked up during a prenatal ultrasound, though most infected babies appear normal.

Will you be screened for toxoplasmosis in pregnancy?

Because the rate of infections are low and results are not always reliable, The American College of Obstetricians and Gynecologists (ACOG) doesn't recommend screening pregnant women, with the exception of those who are HIV-positive or when infection is suspected.

Talk about the pros and cons of testing with your doctor or midwife, and together you can make a decision that's right for you. And be sure to call your caregiver if you have swollen glands or other reasons to suspect you've been infected.

If it seems as though you might be infected, your blood will be tested to measure your levels of two antibodies. Depending on the results, you may need to be tested again in two to three weeks and have your blood sent to a toxoplasmosis "reference lab." This is done both to confirm the initial results and to help determine approximately when you might have become infected.

What will happen if you have toxoplasmosis?

If test results suggest that you have toxoplasmosis during pregnancy, your practitioner may treat you with an antibiotic to help reduce your baby's risk of neurological problems from the infection. The antibiotic chosen will depend on how far along you are in your pregnancy; one is given before 14 weeks and a combination of another two is given at or after 14 weeks.

(Antibiotic treatment to prevent transmission of the infection to the baby has not been proven successful.)

Since not all maternal infections are transmitted to the baby, you may have an amniocentesis to determine whether your baby also has the infection. (The lab will do a special DNA test on your amniotic fluid to check for the presence of the parasite.) You'll also have a series of ultrasounds throughout your pregnancy to look for abnormalities in your developing baby.

If your amniotic fluid shows that your baby has been infected or an ultrasound shows a problem, you'll probably be referred to a maternal-fetal medicine specialist for care. You may also want to talk to a genetic counselor about the risks to your baby. Depending on your baby's gestational age, you'll be given the option to end the pregnancy.

What will happen if your baby has toxoplasmosis?

If your baby tests positive for toxoplasmosis at birth, they'll be treated with antibiotics for about a year, even if they have no symptoms. Special hearing and eye exams will be done, as well as a sonogram or CAT scan of their head and other tests as needed.

About 10 percent of babies with toxoplasmosis have symptoms at birth, such as:

• Eye infection
• Enlarged liver and spleen
• Jaundice
• Pneumonia

If not treated, up to 90 percent of newborns with toxoplasmosis - whether or not they had symptoms early on - may have serious consequences months or even years later, including:

• Intellectual disabilities
• Vision problems, blindness
• Cerebral palsy
• Seizures
• Hearing loss

Studies show that although treatment after birth may not reverse all the damage that occurred before birth, it will greatly reduce a baby's risk of developing new problems during infancy and beyond.

Learn more:

• Pregnancy symptoms you should never ignore
• Foods and beverages to avoid during pregnancy