This ruby red herbal tea is a delicious caffeine-free drink with lots of health benefits. But some experts have warned that pregnant women should not consume hibiscus. In this article, we’ll take a look at these hibiscus tea pregnancy worries and consider whether you should avoid drinking it while pregnant.December 21, 2021 6:43 pm December 28, 2021 6:42 pm
A quick recap on hibiscus
Before we get started, we’ll include a very quick reminder on the basics of hibiscus. This special flower has been used in traditional medicine for generations.
There are a few different species under the family name ‘hibiscus’, including Hibiscus sabdariffa.
It is famed for its benefits for your blood pressure, blood sugar levels and cholesterol levels. Scientists have discovered that it is packed with antioxidants such as polyphenolic acid, flavonoids and anthocyanins. Furthermore, it may even help with weight loss.
The most popular way to consume hibiscus is in the form of a tea, which you can make by brewing the petals or calyces in water. However, it is also available in the form of a powder which can be added to smoothies, desserts and other recipes.
For more information on the health benefits of this colourful flower, head over to our article on hibiscus health benefits.
What are the concerns about hibiscus in pregnancy?
There are a couple of concerns around consuming hibiscus while pregnant. These mostly centre around hibiscus’s ability to interfere with your hormones (and potentially those of your baby).
Before we deal with those, it’s important to note that all of the scientific evidence we could find relates to non-human studies conducted on animals.
There is little to no evidence for the safety of hibiscus in pregnant women. However, after observing some unwanted side effects in animals, the authors of the animal studies have strongly advised that pregnant women avoid hibiscus until more is known about its effects in humans.
Now, onto the concerns that experts have around hibiscus.
Hibiscus might help stop an embryo from implanting
A number of studies have found that treating animals (usually rats) with hibiscus stopped embryos from implanting into the wall of the uterus. This must happen to ensure that that the embryo develops into a foetus and the pregnancy continues successfully.
It’s unclear from the research exactly how this happens. Some studies observed that the zygote (fertilised egg) formed successfully but wasn’t able to implant.(1) Meanwhile others suggest that hibiscus might stop the zygote or blastocyst (very early embryo) from forming correctly.(2)
Researchers also theorised that hibiscus might be contributing to creating an unfavourable environment for implantation in the womb.(2)
Both of the studies mentioned above used a species of hibiscus called Hibiscus rosa sinensis which is closely related to Hibiscus sabdariffa.
As a result, the authors of the studies strongly advised that hibiscus should be avoided during the early stages of pregnancy.
It may alter the pattern of your periods and ovulation
One study gave women with irregular periods either an unrefined papaya tea or a hibiscus tea. After two months, the women who had taken hibiscus tea exhibited changes in their symptoms.(3)
Some people believe that hibiscus is an ‘emmenagogue’, which might explain its effects on your menstrual cycle. An emmenagogue is a type of herb which is thought to stimulate blood flow to the pelvic area and your uterus.
While this may be very useful if you’re trying to keep irregular periods under control, it’s possible that altering your hormone levels could cause problems if you’re pregnant.
A different study on albino mice showed that hibiscus caused changes in their menstrual cycle. In this case, they were in heat (estrous) and the period immediately after, when the uterine wall is built up (metestrous) for longer.
It also caused changes in the ovaries which suggested that the rats were not ovulating as usual.(4)
As a result you should avoid hibiscus if you are trying to conceive or are in the early stages of pregnancy. This is because we don’t know if the symptoms experienced by the albino mice in the study might also be reflected in humans.
"Some people believe that hibiscus is an ‘emmenagogue’, which might explain its effects on your menstrual cycle. An emmenagogue is a type of herb which is thought to stimulate blood flow to the pelvic area and your uterus."
Hibiscus may be oestrogenic
The researchers who conducted the study on albino rats mentioned above concluded that some of the effects they noticed could be down to oestrogenic activity.(4)
This essentially means that hibiscus affects the hormone oestrogen and may alter its levels in your body.
Other studies have also noticed key signals that hibiscus might affect oestrogen levels. These include an increase in the weight of the uterus and uterine growth.(2)
Given that oestrogen plays a crucial role in successful pregnancy, helping to nurture your baby from the first trimester right the way through to the third, it’s unwise to consume anything that might interfere with it.
The authors of one study noted that oestrogen and progesterone regulate all the crucial stages of early pregnancy. Even a slight shift in the balance might result in your uterus not providing the ideal environment for the development of your baby.(2)
While little is known about how hibiscus affects oestrogen in humans, the evidence from animal studies suggests we should be cautious about taking it while pregnant.
It may change your contractions
Some cultures use hibiscus as a method of inducing labour. In fact, it is listed in a Handbook of African Medicinal Plants for exactly this purpose.(5)
A study on rats looked at whether hibiscus affected contractions, both in the bladder and uterus. The researchers concluded that hibiscus did inhibit both the strength and frequency of contractions in both areas.(6)
However, the researchers were not sure exactly how or why this happened.
If your baby is overdue, it might be tempting to try a traditional method of helping things along. However, the mechanisms for why hibiscus might work to induce labour are unclear. It’s safest to leave inducing labour in the hands of medical professionals.
Some hibiscus products may contain aluminium
A recent review of the health benefits of hibiscus published in ‘Nutrition and Food Technology: Open Access’ cautioned that pregnant women or people with kidney issues should not consume hibiscus tea.
This is because hibiscus may contain aluminium.(7)
Aluminium is dangerous during pregnancy as it may affect the cognitive development of the baby.(8) However much of this evidence comes from animal studies.
Another area of concern is that research investigating metals including aluminium suggests that they may play a role in miscarriage.(9) However, once again very little is known about how this might work.
It’s likely that we all have a small amount of aluminium in our bodies thanks to inhaling it, consuming it in our water or getting it from our food supply. We might also consume some of it from cooking tools and foils containing aluminium.(10)
The EU has established a tolerable weekly intake of 1mg aluminium per kilo of body weight per week.(10)
While consuming a small amount of aluminium isn’t a problem for most of us, some herbs including hibiscus seem to be naturally quite high in it.(11)
This is another good reason to avoid hibiscus during pregnancy as a precaution.
Hibiscus and pregnancy: the verdict
Studies examining the safety of hibiscus in human women are extremely thin on the ground. However, studies in animals have raised possible areas of concern for hibiscus tea in pregnancy.
Scientists have also proposed certain reasons for how hibiscus affects the fertility of certain animals. Some of these (such as its effects on oestrogen) might carry over to human beings. At this stage, we simply don’t know.
Because there is so much uncertainty about the safety of hibiscus during pregnancy, and because its plausible that it might contribute to unsuccessful pregnancy or health issues for mum and baby, it’s our strong advice that you do not consume hibiscus while pregnant. This is simply a precaution reflecting the lack of available information to prove its safety.
The same advice applies if you are trying to conceive, as some animal studies suggest that it might interfere with the early stages of pregnancy.
What about breastfeeding?
In some areas of the world, such as Nigeria, the seeds of the hibiscus plant are used to help promote lactation.
While there isn’t any scientific evidence of this in animal subjects, in vitro studies on animal cells have suggested that hibiscus might promote lactation.
However, once again there is little to no safety information available, and the authors of the study suggested that ‘caution should be exercised’ with hibiscus during pregnancy and lactation until we know more about its safety.(12)
What alternatives are there?
Keen to replace your usual hibiscus tea with something else while you are pregnant, trying to conceive or breastfeeding?
The American Pregnancy Association has a helpful list of the herbal teas which are considered ‘likely safe’ during pregnancy. You can check out their recommendations of which teas to choose and which to avoid by heading to their article on herbal teas during pregnancy.
You may also like to consult your doctor to make sure any herbal teas you drink will be safe for you and your baby.
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