A pregnant woman with a high level of naturally occurring immunoglobulin M antibodies to Toxoplasma gondii.

A pregnant woman diagnosed as positive for immunoglobulin M antibodies to Toxoplasma gondii did not have a subsequent rise of specific immunoglobulin G antibodies until delivery. The antibodies were therefore considered as naturally occurring immunoglobulin M antibodies. The baby was completely normal without any clinical and serologic signs suggestive of congenital toxoplasmosis.