Herbs in pregnancy: not everything what’s natural is safe

by | Jul 28, 2019 | Happy Pregnancy | 0 comments

USE of medicinal herbs in pregnancy is the subject that always raises many questions. The reason is that their use in the treatment of classic pregnancy disorders is very common but not entirely clear from a safety point of view.

However, it is important to be aware that natural is not always the synonym for safe especially when it comes to pregnancy.

In this article, I want to show you which medicinal herbs can be considered relatively safe for their consumption during pregnancy, which must be limited and which must be categorically avoided.

Are you ready? Let’s go

“Even harmless chamomile looks like the devil!” This is the desperate request of one soon to be mum who asked me for clarifications on the safety of medicinal herbs in pregnancy.

Why it’s so difficult to value the efficacy and safety of herbs in pregnancy?

Historically speaking the use of herbs for the treatment of common discomforts that arise during pregnancy and labour dates back at least to ancient Egypt.

The problem is that they don’t always produce the same effects in different parts of the world and from the scientific point of view there is no confirmation of their efficacy and above all safety. This is because many studies have not been formally “approved” and the ethical dilemma remains when testing on pregnant women

Most of what is currently known about the use of herbs during pregnancy is based on historical, empirical and observational evidence with some pharmacological studies and animal tests.

Furthermore, their effectiveness depends on their concentration and dosage. What works for one person can cause harm to another or be completely neutral.

However, there is one important thing to emphasize.

Lack of evidence of harm doesn’t mean is safe. Some of the harmful effects of herbs may not be immediately noted until their use has been interrupted or they could only occur with prolonged consumption.

It is therefore important to be well informed and to use only those herbs identified as safe from scientific evidence.

Herbs in pregnancy: which ones are safe

The safest approach to use herbs during pregnancy is to avoid them during the first trimester when the fetus (still the embryo) is more susceptible to damage such as more or less severe malformations. It is important not only what is consumed but also the doses and the form of herbs (eg essential oils or extractions).

Beverages and herbal teas (for example raspberry, spearmint, chamomile, lemon balm, nettle, dog rose, rooibos, linden, valerian, passionflower, fennel) are considered safe in moderate amounts for regular use during pregnancy.

Here some of their characteristics:

Raspberry leaves

 Literally, they are dried leaves of raspberry plant and even if their aroma is pleasant, it doesn’t seem to be the one of raspberry.

In addition to dried leaves, you can find them in powder, in tablets and tinctures.

Many herbalists and midwives suggest raspberry leaves’ supplements (herbal teas, tinctures) in the second and third month of pregnancy to help strengthen, tone and prepare the uterus and cervix and induce or facilitate labour

From a nutritional point of view, raspberry leaves are rich in minerals (calcium, iron), vitamin C and some antioxidants as rutin effective in reducing inflammation.

The medicinal efficacy of raspberry leaf herbal tea in inducing and facilitating childbirth has not been scientifically proven but there are also no contraindications to its consumption in pregnancy

At the most you can benefit of its antioxidants and minerals. Its aroma is pleasant, slightly bitter. To prepare it, pour a teaspoon of raspberry leaves and boiling water into a cup, then leave to infuse for five minutes.


It is the most studied herbaceous plant for its effects in pregnancy especially in reducing nausea and vomiting. Ginger has been used for centuries as the natural remedy against nausea and is considered universally safe when taken during pregnancy.

You can try the infusions of fresh ginger, ginger teas, crystallized ginger (better without sugar) and ginger popsicles.

The ginger beverages or ginger ale don’t contain enough quantities so it is better to avoid them also due to their high sugar content.


Used in the form of herbal teas, it helps in relaxation and induces sleep.

Did you know that chamomile is the most used herb in pregnancy but scientific evidence on its safety is lacking?

Some studies suggest that it could stimulate uterine contractions

A recent study from 2016 confirmed that in women who were in the 40th week of pregnancy, chamomile pills with a very high dose (3000 mg/day) were effective in inducing labour. The birth began in 92.5% of the women who took chamomile supplements during one week versus 62.5% who took the placebo tablets.

It’s worth emphasizing however that a cup of chamomile taken occasionally is not strong enough to cause contractions, but you should be careful if you consume high quantities of chamomile during pregnancy or there are signs of premature birth.

Drinking chamomile in the postpartum phase can have galactogen effects (increase in milk supply), improve sleep and reduce postpartum depression.

Also, the use of herbs in the kitchen such as oregano, thyme or parsley is safe, indeed they are the rich source of antioxidants and folate.

The following table provides an overview of a range of herbs that have been shown to be safe for use during pregnancy through clinical trials or scientific evaluation


Herbs in pregnancy to avoid

While some medicinal herbs are safe in pregnancy, there are others that should be avoided.

In the halfway between these categories, there are herbs which use is not appropriate for daily intake but can be used, if necessary, for short periods in some specific treatments

Liquorice is a perfect example of such a herb. Consumption for a few days due to sore throat, for example, for no more than a week, can be completely safe, however, it is contraindicated in patients with hypertension and even candies containing the liquorice extract for a prolonged period has been associated with the risk of preterm birth.

Topical applications, including vaginal use (ie for the treatment of vaginal infections), of most herbs are considered safe, however, some herbs, such as phytolacca root, Roman mint oil (or pennyroyal) and thuja oil, are toxic and should be avoided internally and locally

Concentrated formulas such as extracts of herbs or essential oils must be used very carefully during pregnancy. A study on the on mice fetus exposed to the 5 common essential oils (oregano, thyme, cinnamon, cloves and sage) has shown adverse effects on the embryonic development of all these oils with the exception of thyme essential oil.

What are their effects on human pregnancy, it’s not known, however it is always better to be cautious

Below is the (non-exhaustive) list of herbs representative of each category that should absolutely be avoided during pregnancy.

The use of herbs that prepare for labour

Some herbs are used during the last weeks of pregnancy to tone and prepare the uterus for labour. In the past, they have been used to facilitate childbirth and make it faster.

Already mentioned raspberry leaf tea is safe in pregnancy and makes it an excellent beverage to prepare for childbirth

But there are other different medicinal herbs that are very questionable from the point of view of their safety, which are still used today as partus preparators: blue cohosh or blueberry root (Caulophyllum thalictroides), black cohosh(Cimicifuga racemosa), partridge berries (Mitchella repens ), nard and its essential oil and castor oil and evening primrose oil among others.

The use of these herbs to prepare the woman for labour immediately raises the question. Why should we use herbs to prepare the body for something it naturally knows how to do?

Furthermore, the safety of these herbs is questionable. In the literature, clinical cases have been reported that suggest an association between blue cohosh and episodes of heart attack or stroke in newborns after the mother has taken the blue cohosh to induce labour.

The blue cohosh contains a series of powerful alkaloids including methylcystine and anagirine, the latter, which is known to stimulate heart muscles. Other side effects of blue cohosh include headache and nausea.

However, the use of blue cohosh is one of the medicinal herbs widely used by midwives together with evening primrose oil that seems to soften the cervix and prepare it for labour but some studies have shown that, on the contrary, they can increase the time of labour and risk of complications


Medicinal herbs considered safe can provide relief when dealing with common pregnancy disorders.

The green light is for the most common herbal teas: chamomile, lemon balm, valerian, linden, hawthorn, nettle, mint, passionflower and fennel (often used in case of abdominal swelling and flatulence) always respecting common sense – a couple of cups a day varying the compositions.

The power of herbs should not be underestimated during pregnancy and therefore they should be used with caution.

However, many herbs are contraindicated on the basis of very limited results, lack of evidence, incomplete studies. So the rule is that not everything that is natural is safe

If you have any doubts about the effects of medicinal herbs, forget it. My advice is always to consult an experienced doctor and herbalist before choosing herbal supplements

Did you used or do you use regularly herbs in pregnancy? What’s your experience? Please share below