Herbal products use during pregnancy: prevalence and predictors.

Purposes: (1) Measure the prevalence of herbal product (HP) use, alone, and concomitantly with prescribed medications during pregnancy, (2) identify the most frequently consumed HP during gestation and (3) determine predictors of HP use at the beginning of pregnancy, and during the third trimester.

Methods: A questionnaire was mailed to 8505 women selected from the Quebec Pregnancy Registry which was created by the linkage of three administrative databases: RAMQ, Méd-Echo and ISQ. Women were eligible if they were continuously insured by the RAMQ drug plan for at least 12 months before the first day of gestation and during pregnancy, and if they gave birth to a live born between January 1998 and December 2003 in one of the Quebec's hospitals. Women with diabetes and psychoses, and women who delivered a baby with birth defects were selected first. Descriptive statistics and multivariate logistic regression models were used to analyse data.

Results: Of the 3354 women (39%) who answered the questionnaire, and were included in the study, nine per cent used HP during pregnancy. 69% of users took at least one prescribed medication concomitantly. Chamomile, green tea, peppermint and flax were the most frequently HP used. Multivariate analyses showed that body mass index (BMI), multivitamin use and one to three prescribed medications used before pregnancy were predictors of HP use at the beginning of pregnancy; adherent women, smokers and users of HP prior to pregnancy were predictors of HP use during the third trimester.

Conclusion: HP use alone and concomitantly with prescribed medications during pregnancy is common, and needs to be addressed by health professionals.