Maternal infection with toxoplasma gondii in pregnancy and the risk of hearing loss in the offspring.

The aim of this study was to investigate the association between maternal infection with Toxoplasma gondii (T. gondii) in pregnancy and subsequent risk of hearing loss in the offspring. The study included 27 727 children born in Norway 1992-1994. Maternal toxoplasma infection during pregnancy was ascertained by serological examination and fetal infection was ascertained by parasite detection in amniotic fluid and/or postnatal serological examination. Hearing loss was defined as mean hearing loss >35 dB HL in the better ear averaged over the pure-tone hearing thresholds at 500, 1000, and 2000 Hz, and the children were identified through linkage to the Norwegian Registry of Hearing Loss in Children. Twenty-two of the 27 727 children (0.08%) were diagnosed with hearing loss. Forty women had primary T. gondii infection in pregnancy. None of their offspring had hearing loss. There was also no association between T. gondii infection prior to pregnancy and hearing loss in the offspring. Hence, we did not find any association between T. gondii infection in pregnancy and hearing loss in the offspring.