Benefits and risks of herbal medicine use during pregnancy on offspring outcomes: A systematic review and meta-analysis of randomized controlled trials and observational studies

Abstract

Purpose

Herbal medicines are widely used during pregnancy, yet their potential effects on offspring remain uncertain. This systematic review aimed to comprehensively evaluate both the potential benefits and risks of prenatal herbal medicine use on offspring outcomes by synthesizing evidence from randomized controlled trials (RCTs) and observational studies.

Methods

We searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials from inception to November 9, 2024. Eligible studies reported maternal use of herbal medicines during pregnancy and assessed offspring-related outcomes.

Results

A total of 111 studies met the inclusion criteria, comprising 39 RCTs, 36 cohort studies, 18 case–control studies, and 18 cross-sectional surveys. In RCTs, prenatal use of certain herbal medicines was associated the live birth rate (RR=1.14, 95 % CI: 1.05–1.24) and a lower risk of birth defects (RR=0.46, 95 % CI: 0.22–0.94), primarily among women undergoing assisted reproduction; reductions in miscarriage were observed among those with threatened or recurrent miscarriage. At the overall level, observational studies adjusted for confounding did not show significant associations between prenatal herbal medicine use and major adverse offspring outcomes (including birth defects, miscarriage, stillbirth, or preterm birth). Exploratory analyses of individual herbal products suggested that some specific herbs—such as almond oil and Glycyrrhiza (with preterm birth), betel quid (with low birth weight), An-Tai-Yin (with musculoskeletal malformations), khat (with nervous system malformations), and Coptidis Rhizoma (with nervous system and genital organ malformations)—may be linked to increased risks. However, these signals were based on a limited number of studies and should be interpreted with caution given variability in exposure definitions, study quality, and potential residual confounding.

Conclusions

For women undergoing assisted reproduction or those at increased risk of miscarriage, certain herbal medicines may offer potential benefits during pregnancy. Overall, evidence from RCTs and adjusted observational studies does not indicate a clear increase in adverse offspring outcomes associated with prenatal herbal medicine use. Nonetheless, a few herbs have been linked to potential safety concerns, although the supporting evidence remains limited and heterogeneous. Cautious use is advised, particularly for products without robust data on fetal and long-term postnatal safety.