Herbs during pregnancy

2.19.1

The safety of herbs during pregnancy

The difficulties in evaluating the safety and risk of herbal therapies are known, and are faced by everyone who takes, or is considering taking, herbs. These concerns are enhanced in pregnant women, and risks are even more difficult to evaluate. The problems of determining the safety of herbs in this context are as follows:

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  There are few published clinical trials or investigations of these substances establishing the efficacy and/or toxicity of the preparations at specific doses.

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  There are no clinical studies of a sufficient number of women to evaluate meaningful safety effects of an herb or herbs on pregnancy outcomes ( ).

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  There are limited standards for the preparation and for the established amounts of specific ingredients in the products marketed, and there are few regulating bodies that certify the products sold or doses used (for example, the US Food and Drug Administration (FDA), the European Medicines Agency (EMEA) and the European Evaluation Food Safety Authority (EFSA)). The German Commission E does provide some oversight on selected herbal products ( ).

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  There are differing health claims made by the agencies in Europe, the United States, and other countries around the world.

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  Some of the products available worldwide may contain (and in some instances have been shown to contain) contaminants such as lead and/or arsenic from the agricultural or manufacturing processes. These could have devastating effects on the pregnant woman.

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  It is always important to know the potential side effects of anything we take, and this is even more significant during pregnancy. The fetus grows rapidly, and is vulnerable to substances that affect cellular growth and division. In addition, certain herbs and natural substances can affect the muscle tone and circulation of the uterus, and some can act as uterine stimulants, abortifacients or teratogens ( ).

2.19.2

Counseling a pregnant woman about herbs

For the above reasons, it is difficult even for an experienced healthcare provider to counsel a pregnant woman on the use of herbal preparations. As providers, evidence-based medicine is expected. However, few herbs and natural therapies even have good scientific evidence, never mind the evidence-based medicine that people expect today. Rather, herbal therapies use more traditional evidence as their proof of safety. This is evidence passed down by culture and tradition, and is often only oral. There is almost no solid scientific evidence regarding the benefits or the risks of herbs in pregnancy to the mother or fetus. It is difficult to reassure patients under these circumstances.

There is some good news, though. There is a considerable body of traditional evidence that can be used as a basis for a discussion with patients. This is traditional evidence – a different kind of evidence-based medicine. It can be very helpful to patients, when put in the proper perspective and used with appropriate understanding. This chapter presents the latest and best evidence that is available, to help counsel pregnant patients, and is organized to optimize the thinking and approach to understanding the most up-to-date knowledge regarding the safety of herbs during pregnancy.

Following a general discussion of herbs during pregnancy, descriptions of some of the frequently used herbs during pregnancy are presented here, along with the best evidence available regarding their safety and risk assessment during pregnancy. Next, there is a description of some common herbs where there is controversy over their use during pregnancy. Again, there is a description and discussion of the latest known evidence for these herbs. Finally, there is a list of herbs thought to be contraindicated during pregnancy. These are organized into groups according to how they might negatively affect a pregnant woman. This can be helpful in terms of counseling a patient.

This chapter focuses on herbal preparations for the pregnant woman. It does not include information on ayruvedic preparations ( ), Chinese herbs ( ) and/or medicines, or homeopathy , where evidence-based safety data for the pregnant woman are even more limited.

Sections and tables are presented identifying herbs where there is some evidence supporting the safety of their use during pregnancy, but only at the doses and in the preparations mentioned. It should be emphasized that any product can have potential adverse effects, based upon the quantity or doses used. Since manufacturing standards have not yet been established, it is impossible to be certain of the dosage in many products manufactured around the world. While manufacturers in developed countries have tried to establish more defined preparations, this still remains an area of concern. In addition, the stability of products and possible contamination of the plant or product grown in other parts of the world may still be an issue because of the lack of regulatory standards. Therefore, it is a requirement for any consumers of these products, and the provider counseling them, to evaluate carefully the stated preparation of each product used, focusing upon the reported concentrations of the ingredients, the country of origin, the manufacturer and its reputation, and any reported incidents of contamination for that type of product. For pregnant or lactating women, or any woman of reproductive age, further caution is necessary because of the potential for enhanced effects of these substances on the mother, the embryo/fetus, and the breastfed baby. With regard to purity and the safety of specific products, there are two valuable and important resources. Consumer Labs ( www.ConsumerLab.com ) is an independent laboratory for the testing of herbal, vitamin, and mineral supplements. A subscription service at ConsumerLab.com is a valuable resource for any provider who counsels patients, including pregnant women, about the purity of specific brands of natural substances.

The United States Pharmacopeia (USP) is also a useful reference.

2.19.3