During pregnancy, many physiological changes occur such as nausea, vomiting, constipation, and heartburn. In addition, psychological changes such as depression may also be observed. In order to cope with such problems, pregnant women frequently turn to herbal products. Easy access to herbal products without a prescription leads them to replace prescribed medications, and this process is not under medical supervision. Another reason for this tendency is the perception that herbal products are natural and harmless. However, plants and herbal products contain many active components. Regardless of whether their structures are fully understood or not, they are chemical compounds just like medications. The regulation of these herbal chemical compounds is not as strict as that of pharmaceuticals. Their actual effectiveness has not yet been proven by scientific research methods, and their safety is not well established.

The frequency of herbal product use during pregnancy and the types of herbs used vary depending on cultural and regional factors. Many studies show that the use of herbal products among pregnant women is quite high (1).

According to the World Health Organization, nearly 80% of the population in Africa relies on traditional medicine for primary healthcare, and in China, the use of herbal products constitutes 30–50% of total medical product consumption. In Europe, North America, and other developed regions, more than 50% of the population has used complementary or alternative medicine methods at least once (2). Studies conducted among Asian populations show that 50% of individuals use one or more herbal products. A recent study in Turkey indicates that approximately 47.3% of pregnant women use at least one herbal product (1).

When we examine commonly used herbal products during pregnancy, their traditional uses, and possible effects:

Sage: Used for flu, vomiting, heartburn, abdominal pain, infections, and toothache. It should not be used during pregnancy due to its abortifacient effects, meaning it can induce labor or cause miscarriage (2).

Black cumin (Nigella sativa): Used for colic, gas, as a dietary supplement, and believed to eliminate infections. Scientific data regarding its safety during pregnancy are insufficient. At doses higher than those commonly used in food, it is thought to slow or stop uterine contractions (2).

Green tea: Used for its sedative properties. Consumption in moderate amounts as tea is considered safe; however, pregnant women are advised to avoid excessive intake due to its caffeine-like content (2). Reports of liver damage associated with its use have also begun to emerge (3).

Thyme: Commonly used among the public for flu, cough, indigestion, and infections (pharyngitis, urinary tract infections, bronchitis). There is insufficient data from human or animal studies; however, it may be potentially harmful due to its labor-inducing and abortifacient effects (2).

Cumin: Used for bloating, abdominal pain, and to facilitate labor. Data regarding its safety in pregnant women are lacking. It is used in India due to its labor-inducing and abortifacient effects (2).

Eucalyptus: Used via inhalation to relieve respiratory problems. It should only be used topically, and oral use should be avoided (2).

Aloe vera: Applied locally for stretch marks. When used this way, it does not pose a known risk for pregnant women. However, Aloe latex contains anthraquinones that can stimulate the uterus, potentially inducing premature labor or miscarriage; therefore, internal use during pregnancy should be avoided (2). Aloe vera beverages, although not common in our country, are available abroad and are used for constipation by stimulating intestinal smooth muscles. However, they may also stimulate uterine muscles, causing contractions, and should therefore be avoided. A similar effect may occur in the fetus, leading to defecation in the amniotic fluid before birth (4). Additionally, aloe vera consumption has been associated with bowel cancer.

Castor oil: Similar to aloe vera, it stimulates intestinal smooth muscles and may also stimulate uterine muscles, potentially inducing labor; therefore, its use should be avoided. It may also affect the fetal intestines, causing serious complications such as fetal defecation before birth (4).

St. John’s Wort: Commonly used as a wound healer, antidepressant, and sedative. Animal studies have shown that it reduces pregnancy rates and offspring numbers, may cause embryotoxicity, reduces uterine muscle tone, and may potentially delay labor (5).

Chamomile: Has sedative, relaxing, diuretic, and antibacterial effects. It is used by pregnant women for flu, cough, stomach/abdominal pain, vomiting, chest pain, gas pain, pharyngitis, and sleep disorders. Recent studies have shown that regular use in pregnancy may increase the risk of miscarriage and preterm birth, may increase bleeding due to its coumarin content, and excessive use may induce contractions and result in low birth weight. Due to its potential to induce menstruation and abortion, it should not be used during pregnancy (2). It should also be noted that chamomile is highly allergenic.

Mint: Used since ancient times for gastrointestinal problems such as gas, bloating, stomach pain, and abdominal pain; respiratory problems; and conditions like muscle pain, headache, and toothache, as well as for sedation. Although it is used together with ginger to prevent nausea and vomiting during pregnancy, excessive use may trigger uterine bleeding in early pregnancy. Therefore, it is considered contraindicated during the organ development period of the fetus, and excessive use during pregnancy is not considered safe (2).

Echinacea: Used to support the immune system against upper respiratory infections. A study involving 54 participants showed no such effect, and allergic reactions were reported (6). In a prospective cohort study of 206 pregnant women who used echinacea during the first trimester, respiratory symptoms improved compared to the untreated group, and no fetal anomalies were observed (7). Although its effectiveness for colds is not fully proven, long-term use (> 8 weeks) may lead to liver dysfunction (3).

Herbal products are widely used worldwide. Despite their increasing popularity in recent years, there is insufficient scientific data regarding the safety of many herbal products. Especially in pregnant women, the number of reports is very limited. The side effects of many traditionally used products are not fully known. Rational drug use should be promoted, and the misconception that “herbal products are harmless” should be prevented. It should not be forgotten that herbal products may have negative effects on both the mother and the fetus. Therefore, caution should be exercised during pregnancy, and a specialist physician must always be consulted, and the doctor monitoring the pregnancy should be informed.

1,2 Fadime Kahyaoğlu, 3 Buket Demirci

1Celal Bayar University, Faculty of Medicine, Department of Histology and Embryology, Manisa

2İrenbe Gynecology and IVF Center, İzmir

3Aydın Adnan Menderes University, Faculty of Medicine, Department of Medical Pharmacology, Aydın

 

References:

  1. Kıssal A, Güner UC, Ertürk DB. Use of herbal products among pregnant women in Turkey. Complementary Therapies in Medicine 30 (2017) 54-60
  2. Fendoğlu B, Şöhretoğlu D. Use of Herbal Products During Pregnancy. J Lit Pharm Sci 2018;7(3):175-84.
  3. No Alternative to Medicine, Traditional and Complementary Medicine Practices, Turkish Medical Association Public Health Branch, 2017. Editor: Serpil Tütüncü, Nilay Etiler
  4. Weisner J, Knöss W. Herbal medicinal products in pregnancy – which data are available? Reproductive Toxicology 72 (2017) 142-152
  5. Kahyaoğlu F, Gökçimen A, Demirci B. Investigation of the embryotoxic and teratogenic effects of Hypericum perforatum in pregnant rats. Turk J Obstet Gynecol. 2018 Jun; 15(2): 87–90.
  6. Grimm W, Muller H. A randomized controlled trial of fluid extract of Echinacea purpurea on the incidence and severity of colds and respiratory infections, Am J Med 1999 106:138-143
  7. Peter CA Kam, Denise WY Barnett, Ian D Douglas. Herbal medicines and pregnancy: A narrative review and anaesthetic considerations. https://doi.org/10.1177/0310057X19845786