Licorice root, derived from the plant Glycyrrhiza glabra, has been valued for centuries as a sweet food flavoring and a traditional herbal remedy. It is commonly found in teas, candies, and concentrated dietary supplements. For a pregnant person, consumption requires extreme caution due to potential adverse effects on both the mother and the developing fetus. The bioactive compounds in licorice root can interfere with the body’s natural regulatory systems, impacting the course of the pregnancy and the long-term health of the child.
The Mechanism of Risk: Glycyrrhizin
The primary concern with licorice root stems from Glycyrrhizin, also known as glycyrrhizic acid. This triterpenoid saponin is responsible for the root’s distinct sweet flavor and exerts negative effects by interfering with a specific enzyme in the body.
The enzyme is 11-beta-hydroxysteroid dehydrogenase type 2 (11β-HSD2), which is highly expressed in the placenta. This enzyme normally acts as a protective barrier for the fetus. Its function is to convert the active maternal stress hormone, cortisol, into its inactive form, cortisone, before it can cross the placenta.
Glycyrrhizin competitively inhibits 11β-HSD2, weakening this protective barrier. When the enzyme is inhibited, more active cortisol passes from the mother’s circulation into the fetal environment. Elevated fetal exposure to maternal cortisol disrupts the hormonal balance necessary for normal development.
Documented Risks to Fetal and Child Development
The increased exposure to maternal cortisol is linked to several documented risks for the fetus and the child later in life. A primary concern is an increased risk of preterm birth (delivery before 37 weeks of gestation). Heavy licorice consumption, defined as greater than 500 mg of Glycyrrhizin per week, has been associated with a two-fold increased risk of delivering prematurely.
Consumption of licorice during pregnancy has also been linked to lower birth weight, suggesting disrupted fetal growth. For the mother, high Glycyrrhizin intake can mimic the effects of aldosterone, leading to mineralocorticoid excess syndrome. This condition causes sodium accumulation, potassium loss, and a rise in blood pressure, potentially increasing cardiovascular risks.
Long-term studies show potential neurodevelopmental and cognitive effects in children exposed to high levels of licorice in utero. Researchers observed that children whose mothers consumed large amounts of licorice showed lower scores on cognitive tests of reasoning and memory. This cognitive difference was sometimes equivalent to an average drop of seven IQ points compared to children with minimal exposure.
These exposed children were also more likely to exhibit symptoms related to attention deficit hyperactivity disorder (ADHD). The theory is that excess cortisol crossing the placental barrier affects the development of the fetal brain, particularly the hypothalamic-pituitary-adrenal (HPA) axis, which regulates stress response.
Variation in Exposure: Supplements, Teas, and Candies
The risk associated with licorice consumption depends heavily on the concentration of Glycyrrhizin and the form consumed.
Supplements and Extracts
Licorice root supplements and extracts typically pose the highest risk because they are concentrated sources of the bioactive compound. These products can contain Glycyrrhizin levels ranging from 10% to 20% of the extract, with a single fluid extract dose sometimes containing 200–800 mg.
Teas
Herbal teas containing licorice root also carry risk, though the Glycyrrhizin content varies widely depending on the brand and brewing method. Some teas contain levels high enough that drinking just a few cups could exceed recommended daily limits. Deglycyrrhizinated licorice (DGL) is a safer alternative, as it is processed to remove most of the Glycyrrhizin. However, even DGL should be discussed with a healthcare provider during pregnancy.
Candies and Flavorings
Licorice candy and food flavorings represent a complex exposure profile. Many licorice-flavored products, particularly in the United States, use anise oil for flavor, which does not contain Glycyrrhizin and poses no risk. Traditional black licorice candy contains the actual root extract and thus contains Glycyrrhizin. Some high-concentration candies require only a small amount, such as 4.3 grams, to reach a provisional daily limit of 100 mg.
Medical Recommendations and Safer Alternatives
Due to the documented association between Glycyrrhizin exposure and adverse outcomes, most medical experts recommend complete avoidance of licorice root during pregnancy. This includes concentrated supplements, extracts, and teas containing the compound. The safest approach is to assume any product listing Glycyrrhiza glabra or licorice root contains Glycyrrhizin unless certified otherwise, such as DGL.
For common ailments where licorice root might traditionally be used, safer alternatives are available. Ginger is a well-established option for managing nausea during pregnancy. For a sore throat or cough, alternative herbal demulcents like marshmallow root or slippery elm are often considered. However, any herbal product should still be reviewed with a healthcare provider before use. Consulting with a physician or midwife provides the best guidance for managing symptoms while ensuring safety for both mother and baby.