Pregnancy-induced hypertension and congenital hearing loss

It has been suggested that pregnancy-induced hypertension (PIH--pre-eclampsia or toxaemia of pregnancy) may cause sensorineural hearing loss (SNHL) in the offspring. To establish the validity of this concept a clinical survey of the prevalence of congenital hearing loss in relation to PIH in the South East Kent Health District in the United Kingdom over a period of 4 years was undertaken. Description of the temporal bones in a case of PIH is presented. The total number of live births in this period was 12,927, out of which 512 mothers (3.9%) were diagnosed as having PIH. To date 17 cases of bilateral SNHL have been diagnosed in this period (excluding known syndromes, conductive hearing loss and unilateral SNHL). One of the mothers of these children had PIH. It is possible that otologists, in the absence of any obvious cause, have attributed the cause of bilateral SNHL to PIH. Histopathological findings in temporal bones from a 29-week fetus, whose cause of death was severe maternal hypertension, showed massive haemorrhages in the inner ear and middle ear and internal auditory meatus, a frequent finding in temporal bones obtained at autopsy from fetuses and neonates who were born prematurely. This study suggests that PIH per se is unlikely to cause SNHL in the newborn.