Herbal Safety in Pregnancy
Women have depended on herbs to support their pregnancy, providing nutrition and handling minor complaints, for thousands of years. Today, most clinicians are appropriately cautious about using herbs in pregnancy. Safety studies in pregnancy are rare, even for medications, as it is unethical to expose women to compounds of unknown safety during pregnancy. Therefore, objective scientific data on the safety of herbal medicines during pregnancy is lacking.1
Based on geographical surveys, the prevalence of herbal medicine use in pregnant women across the world is on the rise. According to a study published in 2016, herbal use in pregnant populations ranges between 7% and 55% among different geographical, social and cultural settings and ethnic groups.2 Studies have shown that while women sometimes use herbal medicines at the recommendation of their healthcare providers (primarily not in the United States), even in locations with a strong herbal history, most of the recommendations come from family members and friends versus healthcare providers.
Some of the herbal medicines most readily used during pregnancy include red raspberry leaf, ginger, licorice (as DGL form), Echinacea, elderberry, valerian and holy basil.
Red Raspberry Leaf
A tonifying herb for the uterus and reproductive system, red raspberry leaf tastes delicious and is a common ingredient in most commercially available pregnancy teas.
There are benefits to women who consume red raspberry leaf tea during pregnancy. A retrospective study of 51 women found a decreased likelihood of premature and overdue labor when red raspberry leaf was taken.3
Another study of 192 low-risk pregnancies gave women 1.2 g of red raspberry leaf twice a day or a placebo, starting in the 32nd week. There was no change between the two groups in the first stage of labor, but the second stage was, on average, 10 minutes shorter. In addition, the red raspberry leaf group had fewer forceps deliveries (19% versus 30%).4 Red raspberry leaf acts as a uterine tonic and allows the uterus to be more productive during labor. There was no increase in birth defects noted in either study. While red raspberry leaf tea has a very mild taste, women who don’t like the taste can mix it with juice or a little juice concentrate.
Ginger is the best-studied herb for nausea and vomiting, including nausea and vomiting during pregnancy. A systematic review of six random controlled trials with 675 patients found that ginger had favorable results for nausea and vomiting. Four studies showed that ginger worked better than a placebo; two showed ginger to be as effective as vitamin B6. In another double-blind study, 70 Thai women experiencing nausea and vomiting were given 250 mg of ginger four times daily; they saw an 80% reduction in vomiting and significant improvement in nausea.5
One study showed ginger to be efficacious against hyperemesis gravidarum, the more severe diagnosis related to prolonged and severe nausea and vomiting during pregnancy.6 A double-blind, randomized, cross-over, placebo-controlled trial of 30 women diagnosed with hyperemesis gravidarum received 250 mg of ginger rhizome four times a day and it provided significantly more effective reduction of symptoms versus placebo.7
In a randomized controlled trial, 120 women who were less than 20 weeks pregnant and experiencing morning sickness were given 1,500 mg of ginger daily for four days. They experienced significant improvements in nausea and vomiting. Post-delivery follow-ups revealed birth weights, gestational age and APGAR scores were within the normal limits.8
Ginger can be taken as a tea, soda, capsules or as candied ginger or cookies.
Licorice root is a delicious herb that is quite popular, due to its helpful impact on the adrenals and demulcent effect in the gut. However, studies have shown an association between heavy glycyrrhizin intake (>500 mg/wk) and shorter gestation9, leaving most forms of licorice contraindicated during pregnancy. It is believed that glycyrrhizin inhibits placental 11 beta- hydroxysteroid dehydrogenase type 2, which acts as the feto-placental barrier to high maternal levels of cortisol. When a woman is exposed to licorice, it opens the pores of the placenta, allowing more of her cortisol to affect her fetus. The placenta loses its protective benefits, meaning that if the woman is under a great deal of stress, so is her fetus. Other outcomes have been observed in children whose mothers were exposed to a high intake of glycyrrhizin during pregnancy, including an increase in attention deficit, rule breaking and aggression problems.
While this may steer you away from using licorice at all, the use of deglycyrrhizinated licorice (DGL) is considered safe and can be very helpful for a common complaint of pregnancy: heartburn. The use of DGL, often prescribed as chews, can be taken as needed without the associated risks of the glycyrrhizin constituent of the licorice.
While colds and the flu are not necessarily more common during pregnancy, they can feel like more of a nuisance when a woman is experiencing other symptoms and might be unable to take her preferred over-the-counter medications or herbal treatments.
There are plenty of lifestyle options that you can turn to when treating a cold or the flu during pregnancy. These include the use of herbal steam inhalations, saltwater gargles or a saline nasal rinse, using a neti pot or a 30 mL or 50 mL syringe.
Echinacea is considered safe for use during pregnancy, with studies to back it up. (According to some studies, it is the most widely used herb by pregnant women.) The first prospective study suggested Echinacea can be safely used for 5 to 7 days during pregnancy without adverse effects, even during the first trimester, which is when organogenesis occurs and is considered the most sensitive time in a pregnancy.
Black elderberry syrup is another favorite herb for immune support; children like it, too! There have been no published trials during pregnancy, but no adverse events have been noted in the literature, according to the American Herbal Products Association’s Botanical Safety Handbook.
Also known as tulsi, holy basil is considered an adrenal adaptogenic herb. While no adrenal herbs have been tested in pregnancy (other than licorice, which is not considered safe), holy basil can be considered if a woman really needs some adrenal support. While lifestyle approaches like exercise and sleep should be the first-line recommendations for stress during pregnancy, this gentle adaptogen may offer some benefit to pregnant moms.
Holy basil is an herb traditionally used to support fertility in both men and women. It has a galactagogue action and is really uplifting, calming and relaxing. Some adrenal herbs, such as licorice or ginseng, are rather stimulating, making them ideal herbs for non-pregnant women who are stressed and tired. These herbs will perk them up. Holy basil is for a woman who is stressed and wired, someone who may get anxious and amped up and needs to calm down to feel more grounded.
Herbs Contraindicated in Pregnancy
While we have discussed some herbs that are great to choose during pregnancy, it is also vital that all practitioners recognize what herbs should NOT be used during pregnancy. These categories of herbs are listed here:
Abortifacients are herbs that will trigger uterine stimulation and get the uterus to contract, which can trigger a miscarriage or an abortion. These include: blue cohosh, cotton-root bark, Thuja, wormwood, rue and pennyroyal.
Essential oils should never be taken internally during pregnancy, but some can be used topically with care and proper dilution. However, if you are not highly comfortable with this product set and population, they should be avoided. Essential oils which should not be used at all during pregnancy include Thuja, oregano, sage, pennyroyal, hyssop, wintergreen, rue, wormwood, anise, tansy, mugwort, parsley and basil and this is not be a complete list.
Teratogens will harm a developing fetus. Lupine and Datura are examples of teratogenic herbs.
Avoid plants that contain strong alkaloids, which can also cause concerns with a growing fetus. These include: comfrey, coltsfoot, borage, goldenseal, barberry, Oregon grape, butterbur and life root.
Stimulating laxatives should be avoided because they cause such strong stimulation in the colon that the cytokines and prostaglandins that are released can often trigger and stimulate the uterus. (This is why castor oil is sometimes used to stimulate labor, as the cathartic laxative effect impacts the uterus as well.) Other examples include: buckthorn, aloe latex and rhubarb. Senna, while having laxative effects, appears to be safe in pregnancy in small doses, such as in use of a tea.
Phytoestrogens such as hops and sage should be avoided due to their hormonal impact on both the mother and the fetus’ gonads, particularly if it is a male child.
Avoid strong nervous system stimulants and depressants, such as ephedra, coffee and kava.
Herbal Safety in Pregnancy
Contradictory findings in the research and recommendations on herbal safety and efficacy can make the task of providing clinical recommendations difficult. A few aspects that can exacerbate the incongruencies are misinformation, adulterated herbal substances, differences in plant parts used and differences in dosing and method of delivery. In conclusion, use the best research available and clinical judgment when it comes to herbal medicine in pregnant populations. When treating women with herbs during pregnancy, I recommend referencing Herbal Medicines in Pregnancy and Lactation: An Evidence-Based Approach and the aforementioned American Herbal Products Association’s Botanical Safety Handbook.
- Smith, C.A., Armour, M., and C. Ee. Complementary Therapies and Medicines and Reproductive Medicine. Semin Reprod Med 2016 Mar;34 (2):67-73.
- John, L.J, and Shantakumari N. Herbal Medicines Use During Pregnancy: A Review from the Middle East. Oman Med J 2015 Jul;30(4): 229-236.
- Parsons M, Simpson M, Ponton T. Raspberry leaf and its effect on labour: safety and efficacy. J Aust Coll Midwives 1999 Sept;12(3): 20-25.
- Simpson M, Parsons M, Greenwood J, Wade K. Raspberry leaf in pregnancy: its safety and efficacy in labor. J Midwifery Women’s Health 2001 Mar-Apr;46(2):51-59.
- Vutyavanich T, Kraisarin T, Ruangsri R. Ginger for nausea and vomiting in pregnancy: randomized, double-masked, placebo-controlled trial. Obstet Gynecol 2001 Apr;97(4):577-582.
- Borrelli F, Capasso R, et al. Effectiveness and safety of ginger in the treatment of pregnancy-induced nausea and vomiting. Obstet Gynecol. 2005 Apr;105 (4):849-56.
- Willetts KE, Ekangaki A, Eden JA. Effect of a ginger extract on pregnancy-induced nausea: a randomized controlled trial. Aust N Z Obstet Gynecol 2003 Apr;43(2):139-144.
- Strandberg TE, Andersson S, et al. Pretern birth and licorice consumption during pregnancy. Am J Epidemiol. 2002 Nov 1;156(9):803-5.
Jaclyn Chasse, ND
Dr. Jaclyn Chasse is a naturopathic physician and the VP of Scientific and Regulatory Affairs for Emerson Ecologics. She proudly serves as the President of the AANP and thinks everyone needs a good probiotic!