In Australia, the incidence of unborn babies being infected with toxoplasmosis is very rare. Only thought to be about 0.25:100,000 to 5:100,000 (0.0000025% to 0.000005%). If a newborn baby becomes infected with toxoplasmosis after birth, they usually have no symptoms or only experience a very mild illness.
If a pregnant woman becomes infected with toxoplasmosis for the first time during her pregnancy, the risk of transferring the infection to the baby increases as the pregnancy progresses, but the more developed the baby is, the less likely they will become unwell. During the 1st trimester (up to 13 weeks) it is thought that up to 17% of babies can become infected, of which about 14% of these will become severely ill or spontaneously miscarry. By the 3rd trimester (after 28 weeks), up to 65 - 72 % of babies will become infected, but hardly any of these babies will become unwell. Therefore, there is a natural protective mechanism in place for the unborn baby exposed to toxoplasmosis.
If an unborn baby does become unwell, the affects can range from mild to severe. This will depend on the baby's
gestation, with those less than 13 weeks more at risk of being severely affected, possibly including: