Use of inhaled corticosteroids during pregnancy and risk of pregnancy induced hypertension: nested case-control study.

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 evenements demographiques. 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 pregnancy induced 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-eclampsia 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.