Licorice Root

Pregnancy

Strandberg et al. (2001) studied 1,049 Finnish women with singleton infants. The heavy-exposure group was at least 500 mg glycyrrhizin per week (110 women). Heavy exposure was associated with birth before 38 weeks (OR 2.5, 95% CI 1.1 to 5.5); birth weight was not significantly lower. Strandberg et al. (2002) compared 95 Finnish preterm births with 107 controls. Heavy exposure was associated with preterm birth, and the early-preterm subgroup before 34 weeks had an adjusted OR of 3.07 (95% CI 1.17 to 8.05). EMA's 2026 assessment summarizes a later reanalysis of the broader under-37-week endpoint as OR 2.18 (95% CI 0.98 to 4.86, p=0.056), which was not statistically significant. The endpoints differ; the early-preterm estimate should not be replaced by the broader reanalysis or described as a replicated result. Choi et al. (2013) prospectively followed 185 singleton pregnancies exposed to OTC or naturopathic formulations containing G. uralensis and 370 controls. The abstract reports a preliminary stillbirth signal, says other fetal outcomes assessed were similar between groups, and calls for larger studies. EMA's assessment notes recall and exposure-definition limitations. The accessible abstract was read; no causal conclusion is drawn. Räikkönen et al. (2009) studied 321 Finnish children at mean age 8.1 years and reported cognitive and behavioral associations with high maternal glycyrrhizin exposure. Räikkönen et al. (2017) studied 378 children at mean age 12.5 years and reported cognitive, memory, attention, and pubertal associations. Räikkönen et al. (2009) and Räikkönen et al. (2017) report observational associations, which do not establish causation. The 2019 systematic review included 74 articles, 47 herbal products, and 1,067,071 women overall; its 3.07 early-preterm estimate repeats Strandberg et al. (2002), not an independent licorice replication. The 2026 systematic review included 111 herbal-medicine studies and searched through 9 Nov 2024. Adjusted observational analyses did not show significant overall associations with major offspring outcomes, while the exploratory Glycyrrhiza/preterm signal was based on limited, heterogeneous studies.

Breastfeeding

LactMed and EMA report that glycyrrhizin can be detected in the breast milk of some licorice users. EMA's 2026 monograph does not recommend use while breastfeeding; LactMed's advice is narrower for long-term, excessive use because of maternal high blood pressure, low potassium, and adrenal-hormone changes. The 1984 Shimada primary abstract describes an HPLC method for ephedrine and glycyrrhizin and says it was applied to milk from patients receiving Kakkonto extract granules, a multi-herb product. The abstract does not report sample count or measured values. No milk concentrations are provided here. The 2026 randomized trial enrolled 104 women with postpartum low milk supply and compared auricular acupressure alone (52 women) with acupressure plus an eight-herb decoction (52 women) for two weeks. LactMed identifies licorice as one ingredient. The trial's combination design cannot identify licorice's contribution to the milk-production results. LactMed reports that licorice-alone trials do not support a milk-supply benefit; prolactin findings are not a direct measure of milk output.

What was tested

Pregnancy evidence includes observational reports on Finnish licorice consumption with estimated glycyrrhizin intake, studies of offspring from those pregnancies, and a Korean cohort exposed to OTC or naturopathic formulations containing G. uralensis. These studies did not provide trimester-specific comparisons. The 2019 review's licorice estimate repeats a Finnish study; the 2026 review includes a wider set of herbal products and identifies only a limited exploratory Glycyrrhiza signal. Breastfeeding evidence includes a milk assay involving Kakkonto, a multi-herb product, and a 2026 trial of an eight-herb decoction combined with acupressure. Neither lactation study isolates licorice as the only exposure.