Objective: To determine whether the use of inhaled corticosteroids during pregnancy increases the risk of pregnancy induced hypertension and pre- eclampsia among asthmatic women. Design: Nested case- control study. Setting: Three administrative health databases from Quebec: RAMQ, MED- ECHO, and Fichier des′ vé ne ments dé mographiques. Participants: 3505 women with asthma, totalling 4593 pregnancies, between 1990 and 2000. Main outcome measures: Pregnancy induced hypertension and pre- eclampsia. Results: 302 cases of pregnancy induced hypertension and 165 cases of pre- eclampsia were identified. Use of inhaled corticosteroids from conception until date of outcome was not associated with an increased risk of pregnancy induced hypertension (adjusted odds ratio 1.02, 95% confidence interval 0.77 to 1.34) or pre- eclampsia (1.06, 0.74 to 1.53). No significant dose- response relation was observed between inhaled corticosteroids and pregnancy induced hypertension or pre- eclampsia. Oral corticosteroids were significantly associated with the risk of pregnancyinduced hypertension (adjusted odds ratio 1.57, 1.02 to 2.41), and a trend was seen for pre- eclampsia (1.72, 0.98 to 3.02). Conclusion: No significant increase of the risk of pregnancy induced hypertension or pre- edampsia was detected among users of inhaled corticosteroids during pregnancy, while markers of uncontrolled and severe asthma were found to significantly increase the risks of pregnancy induced hypertension and pre- eclampsia. Objective: To determine whether the use of inhaled corticosteroids during pregnancy increases the risk of pregnancy induced hypertension and pre-eclampsia among asthmatic women. Design: Nested case-control study. Settings: Three administrative health databases from Quebec: RAMQ, MED-ECHO, and Fichier des’ ne nents de mographiques. Participants: 3505 women with asthma, totalling 4593 pregnancies, between 1990 and 2000. Main outcome measures: Pregnancy induced hypertension and pre- eclampsia. Results: 302 cases of pregnancy induced hypertension and 165 cases of Pre-eclampsia were identified. Use of inhaled corticosteroids from conception until date of outcome was not associated with an increased risk of pregnancy-induced hypertension (adjusted odds ratio 1.02, 95% confidence interval 0.77 to 1.34) or pre- eclampsia (1.06, 0.74 to 1.53). No significant dose- response relation was observed between inhaled corticosteroids and pregnancy induced hypertension or pre-eclampsia. Oral corticosteroids were significantly associated with the risk of pregnancyinduced hypertension (adjusted odds ratio 1.57, 1.02 to 2.41), and a trend was seen for pre- eclampsia (1.72, 0.98 to 3.02). Conclusion: No significant increase of the risk of pregnancy induced hypertension or pre- edampsia was detected among users of inhaled corticosteroids during pregnancy, while markers of uncontrolled and severe asthma were found to significantly increase the risks of pregnancy induced hypertension and pre- eclampsia.