Toxoplasmosis is a common infection caused by the parasite toxoplasma gondii. If you catch toxoplasmosis while you are pregnant (or shortly before becoming pregnant), there is a 40% chance your baby will be infected (1). The infection can cause miscarriage or your baby may be stillborn, have
brain damage or blindness. Even if your baby is born healthy, they might develop problems later in childhood.
The toxoplasmosis parasite is largely passed on through cat feces, for example, in litter trays or in contaminated soil when gardening. Other animals can catch toxoplasmosis from infected soil and the infection can be passed on to humans if they eat raw or undercooked meat. Fresh fruit, vegetables, salads and unpasteurized milk (especially unpasteurized goat's milk) can also be a source of toxoplasmosis.
Therefore, general advice to pregnant women wishing to avoid toxoplasmosis is:
- Avoid changing cat litter or gardening. If you must do so, wear gardening gloves, and wash your hands carefully afterwards.
- Wash your hands thoroughly after handling raw meat and avoid cured meats (such as smoked ham).
- Make sure that all meat is cooked thoroughly and piping hot before eating.
- Wash fruit, vegetables and salads before eating them.
- Don't drink unpasteurized milk or eat other unpasteurized dairy products.
- If you live on a farm, don't handle lambing ewes, their afterbirth, newborn lambs, or the clothing of anyone else involved in lambing. Toxoplasmosis is quite common in sheep so you must follow the recommended advice to avoid infection.
Lots of people have a mild form of toxoplasmosis at some point in their life without realizing it. If this happens, you are immune to the infection from then on and your baby will be protected. Roughly one third of the population will have been infected by the age of thirty. Toxoplasmosis poses a risk to the unborn child as the
immune system is underdeveloped, but not to the mother or to other healthy adults and children.
The time between catching toxoplasmosis and showing symptoms (incubation period) is 2-21 days and it can take 4-8 weeks to pass the infection to your baby. Some people don't have any symptoms; some have symptoms like glandular
fever - feeling sick with a
fever, headache, sore throat and swollen glands.
1st trimester (weeks 0 to 13): if you come into contact with toxoplasmosis, the risk of your baby being infected is about 15%. If it is infected, there is a high risk you may have a miscarriage, or your baby might be born with damage to the
brain or eyes (2).
2nd trimester (weeks 14 to 26): the risk of your baby being infected is about 25%. If it is infected, there is less chance of a miscarriage, but your baby might be born with damage to the
brain or eyes.
3rd trimester (week 27 to birth): the risk of your baby being infected is as high as 65%. If your baby is born healthy, it might develop symptoms such as damage to the eyes later in life. For the first year, your baby may have to have
blood tests every two months to see if they are infected. If they are, they can be given
antibiotics to reduce the chance of developing problems.
Most people who are infected with toxoplasmosis have no symptoms and so do not know they are infected. If you think you may have come into contact with toxoplasmosis, you should see your doctor immediately. You will need to wait three weeks to have a
blood test to see if you've caught the infection. If you have caught it, you may be given
antibiotics called spiramycin to reduce the chance of passing the infection to your baby.
If you are more than 15 weeks pregnant, you may have an amniocentesis test (fluid is taken from around the baby in the womb) and an
ultrasound scan to see if the infection has passed to your baby. Early treatment with
antibiotics such as pyrimethamine and sulfadiazine may reduce the severity of the infection in the baby. These drugs can have side effects, which your doctor will talk to you about.