About 1% of all pregnancies in France are complicated by a primary infection with toxoplasmosis. The risk for the fetus being affected increases during the pregnancy but the seriousness of the effect on the fetus becomes less with more advanced pregnancies. Treatment of the mother using Spiramycin have been proven to be efficient, lessening the risk for the fetus being affected. The diagnosis of the fetus being affected rests on a whole bundle of presumptive evidence culled from non-invasive methods and invasive methods which are not without risk. (Direct or over-enthusiastic diagnostic techniques or none at all). We have studied a series of 101 primary infections with toxoplasmosis for which we have not carried out any invasive diagnostic techniques. The long term results in 77 infants show no difference in fetal morbidity and better results as far as mortality are concerned. We therefore propose simplifying the diagnostic approach in cases of primary infection with toxoplasmosis during pregnancy.