Background: Stevens-Johnson syndrome (SJS) is an acute life-threatening condition often elicited by drugs. The government's indecisiveness in deciding to stop the use of nevirapine (NVP) in HIV-infected pregnant women owing to the increase of SJS among this population group in South Africa prompted this investigation.

Objectives: To investigate if pregnancy is a risk factor for SJS among HIV-infected women taking NVP-containing regimens and registered within the Medunsa National Pharmacovigilance Centre database.

Methods: A matched case-control study with 5:1 matching was conducted. Women with SJS (cases) taking NVP-containing regimens were matched with women without SJS (controls) taking NVP-containing regimens. Controls were randomly selected and matched to cases by hospital, age, treatment duration and CD4 count. Conditional logistic regression was used to determine if pregnancy was a risk factor for SJS.

Results: Six SJS cases were identified and 30 controls selected. The median age of both cases and controls was 29 years and the average CD4 counts were 237 and 234 cells/microl respectively. Subjects were on NVP treatment for 18 - 31 days before the onset of SJS. Controls did not develop SJS after treatment of between 1 and 365 days. Pregnancy increased the chances of developing SJS 14-fold (OR 14.28, p = 0.006, 95% CI 1.54 - 131.82).

Conclusions: NVP-containing ARV regimens taken during pregnancy increase the risk of developing SJS. Healthcare workers are advised to offer informed consent to patients and recommend effective contraception methods if NVP treatment is considered. In the light of our findings, further studies of the association between NVP, pregnancy and SJS are necessary before general conclusions can be reached.