Bell's palsy and tinnitus during pregnancy: predictors of pre-eclampsia? Three cases and a detailed review of the literature.

We present two cases of Bell's palsy, and another with tinnitus, all in association with pre-eclampsia in the third trimester of pregnancy. We also systematically reviewed the published literature on both Bell's palsy and tinnitus in pregnancy and the puerperium using Medline from January 1966 to October 1998, and searched through the references from review articles and original research publications for further studies. Studies were limited to those published in the English language. We then pooled the rates of occurrence for Bell's palsy according to trimester of pregnancy, and postpartum, as well as the associated prevalence of pre-eclampsia or gestational hypertension. We found that the majority of cases of Bell's palsy arose during the third trimester (pooled event rate 71.1%, 95% confidence interval (CI) 64.1-77.2), while almost none arose in the first trimester. During the postpartum period, the distribution of Bell's palsy was 21.3% (95% CI 15.7-28.1) of all cases, with the majority arising within days of delivery. Gestational hypertension or pre-eclampsia was present in 22.2% of cases (95% CI 12.5-36.4), well above the 5% rate in the general population. Only one paper provided data on tinnitus in pregnancy, with the distribution equal across all three trimesters. When compared to non-pregnant controls, the odds ratio for the development of tinnitus during pregnancy was 2.8 (95% CI 1.0-8.1). In conclusion, Bell's palsy, and perhaps, tinnitus, occur more frequently during the third trimester of pregnancy. Both may be presenting prodromal signs of underlying early pre-eclampsia. The pathophysiologic mechanism relating these two entities to pre-eclampsia is also discussed.