Are effects of toxoplasma if you infected for the only first time during pregnant ?

Usually correct: It is not uncommon for routine prenatal labs drawn at the beginning of pregnancy to include toxoplasmosis titers. If you are 'igg' positive, then you have been exposed in the past, and your fetus is protected by your immune system. If you are 'igg negative' then an exposure during pregnancy is potentially harmful. So the answer to your question is, yes.

Toxoplasmosis: The big concern is about affecting the newborn fetus. About 15 percent of babys are affected during the first trimester if mother is untreated.