Toxoplasmosis is a common infection caused by a parasite (toxoplasma gondii), which may present with flu-like symptoms, swollen glands in the neck, muscle pains and fatigue; however, many people have no symptoms at all. Once you have had toxoplasmosis you are immune and will never catch it again. About half of the population have had this infection at some point in their life. There is a low risk of catching toxoplasmosis during pregnancy (about 1 case for every 500 pregnant women in the UK). Symptoms can take 2-3 weeks to appear, and it may be difficult to work out when the infection was contracted. If you think you may have become infected with toxoplasmosis in pregnancy, you should ask your midwife or GP to arrange a blood test.
The infection can be caught by eating food with the parasite in it, e.g. from undercooked and raw meat, unwashed fruits and vegetables, unpasteurised goats’ milk and milk products. It can also be caught from gardening, cat faeces and newborn lambs. Pregnant women should avoid contact with cat litter and lambs. Always wear gloves to garden and if you have to clear out cat litter in pregnancy. Hand hygiene with washing before and after handling food will also reduce the chance of infection.
In pregnancy the infection can pass to the baby (about 40% of cases) and in the early stages it can cause miscarriage or cause serious health problems. Congenital toxoplasmosis may present with blindness, deafness, epilepsy, growth problems or brain damage in the baby, and sadly there is a risk of miscarriage and stillbirth. Diagnosis can only be confirmed by a blood test, which checks for antibodies that are produced in response to the infection. These can take 3 weeks to develop. The presence of antibodies may indicate infection before pregnancy, and a further blood test may have to be performed to confirm if infection has taken place during pregnancy, or if it occurred before pregnancy. Unfortunately, the blood test is not completely reliable and false negative or positive results can occur.
If the blood test shows that you do not have antibodies to toxoplasmosis, you are not immune to the infection and may catch this in the future. You may need to have a repeat blood test in later pregnancy if you think you have become infected.
The likelihood of the baby becoming infected is higher the later in pregnancy the infection occurs, however the effect on the baby is usually less severe in later pregnancy.
If diagnosed in pregnancy, toxoplasmosis is usually treated with antibiotics (spiramycin) to reduce the risk to the baby. If it is thought that the baby is infected, after 15 weeks an amniocentesis can be performed (removing a small sample of amniotic fluid from around the baby at the time of a scan by inserting a needle through the mother’s tummy wall into the womb). If this fluid shows the presence of infection, antibiotics are given to reduce the risk to the baby.
The scan at 20 weeks may also indicate if infection in the baby is likely. Some women will consider termination of the pregnancy if an abnormality is found. Unfortunately, a normal scan does not exclude infection in the baby.
Following delivery, babies who were born with toxoplasmosis are followed up by the paediatrician.