Use of herbal drugs during early pregnancy in relation to maternal characteristics and pregnancy outcome.

PURPOSE: To study characteristics of women using herbal drugs and the possible impact of use in early pregnancy on pregnancy outcome.
METHODS: Data on the use of herbal drugs during pregnancy were obtained from the Swedish Medical Birth Register during the period 1st July 1995 to end of 2004. Women who reported use of herbal drugs were compared to all women giving birth during the period. Outcome variables were prematurity, birth weight, Apgar score, number of infants in delivery and congenital malformations.
RESULTS: Among the 860 215 women in the register, 787 (0.9%) reported use of herbal drugs during early pregnancy. The most frequently used herbal drugs were Floradix (iron-rich herbs), ginseng and valerian. Use of such drugs was independently associated with high maternal age, normal weight and 14-15 years of education. Risk factors for valerian differed from those for other herbal drugs, for example with respect to maternal smoking and country of birth. Concomitant drug use was common and the most frequently used drugs were multivitamins, folic acid, cardiovascular drugs (mainly antihypertensive drugs), non-steroid anti-inflammatory drugs (NSAIDs), analgesics and psycholeptics. None of the infant characteristics studied were influenced significantly by the mother's use of the examined herbal drugs during early pregnancy.
CONCLUSIONS: The most commonly reported herbal drugs used during pregnancy were Floradix (iron-rich herbs), ginseng and valerian. No signs of unfavourable effect on pregnancy outcome were seen. The number of exposures, however, was low and therefore effects on rare outcomes (e.g. specific malformations) cannot be excluded. Copyright 2007 John Wiley & Sons, Ltd.