What kind of raspberry tea is good for pregnancy?

Reviewed by Dan Brennan, MD on September 29, 2020

Red raspberry leaf is part of the raspberry plant that has been used as a traditional remedy for pregnant and postpartum women. Although red raspberry leaf has been cultivated for its culinary and medicinal benefits for centuries, modern science has not been able to confirm all of the claims traditionally made about red raspberry leaf tea.

Raspberry plants are hardy perennials in the rose family. Despite the name, the red raspberry leaf tea doesn’t take like raspberries. It tastes like a common black tea.

Red raspberry leaves are cultivated in northern climates. Their leaves have been touted for their health benefits during and after pregnancy, such as boosting milk supply in lactating women and inducing labor in pregnant women.

However, modern scientific research into these claims has not confirmed health benefits to red raspberry leaf tea, and warns that the herb may even be harmful in some cases. Many studies were conducted using animals and need to be researched further.

One cup of red raspberry leaf tea is not a source of calories or other macronutrients. However, red raspberry leaf is a good source of:

M agnesium
C alcium
Antioxidants

Red raspberry leaf tea is also an excellent source of potassium. Studies have shown that potassium may help keep blood pressure in a health range and reduce the risk of stroke.

Red raspberry leaf is a rich source of vitamins and minerals. However, what makes red raspberry leaf so potent can also create complications for people with certain medical conditions.

Although research has yet to confirm the benefits of red raspberry tea, there are a number of claimed health benefits to drinking it:

Lactation Support

Red raspberry leaf is a traditional remedy for boosting milk production in lactating women. However, clinical research has not shown any benefit to drinking red raspberry leaf tea for women who are breastfeeding.

Although no side effects to drinking red raspberry leaf tea have been detected in these trials, it does contain polyphenols that are detectable in breast milk. Women who are nursing should discuss any use of supplements with their healthcare providers.

Induction of Labor

In a survey of the American College of Nurse-Midwives, 63% of the certified nurse-midwives (CNM) reported using red raspberry leaf as an herbal supplement for labor induction in pregnant women. The most cited reason for the use of red raspberry leaf and other herbal preparations included that they are a “natural” alternative to pitocin.

However, 21% of CNMs reported complications associated with herbal labor stimulants, including early labor, prolonged uterine contractions, nausea, and vomiting.

Weight Loss

Red raspberry leaf has been recommended as a tonic to improve fat metabolism and encourage weight loss. It is often sold as a “detoxifying” supplement meant to improve body composition and overall health.

However, a scientific study found no effects, neither harmful nor beneficial.

Because red raspberry leaf tea contains potent ingredients, you should consult with your doctor before taking it or any other supplement. Consider the following before preparing or drinking red raspberry leaf tea:

Pregnancy Concerns

The effects of red raspberry leaf tea on someone who is pregnant or breast-feeding are inconclusive. Since many studies were conducted using animals, additional research to understand the effects on humans is required. If you’re pregnant or breastfeeding a baby, it is best to discuss any potential risks with your healthcare provider.

Medication Interference

Because red raspberry leaf may interact with some medications, speak to your healthcare provider before beginning supplementation with red raspberry leaf.

Estrogenic Effects

Red raspberry leaf may mimic the effects of estrogen in the body. Speak to your doctor before starting supplementation with red raspberry leaf if you are sensitive to the effects of estrogen.

Red raspberry leaf tea is an ancient tonic—pregnant women as early as the 6th century drank the stuff. It is still a popular herbal supplement for pregnancy today, with claimed benefits ranging from it’s ability to strengthen the uterus and help prepare the body for birth to directly stimulating labor (in one survey, more than half of American midwives said they recommended raspberry leaf to naturally induce).

During my pregnancies, even though I’m a bit of a skeptic, I loved the promise of a magical uterine strengthening elixir as much as the next pregnant gal. Naturally, I ventured into the wilds of internet claims to suss out these potential benefits and I found that the claims varied widely:

From the very direct— “It strengthens the uterus and pelvic muscles which leads to shorter and easier labors.”

To the anecdotal— “…my sister’s sister took it and had a 5 hour labor! Then two pushes and out!”

To the seemingly scientific— “It has been shown to concentrate the effects of contractions to make them more effective.”

But is there actually scientific evidence and biological reasoning behind these claims? Time for digging…

Kinda… maybe… maybe not….

First, I have to point out that the scientific study of the raspberry leaf is weak (at best). In 2009, a team of researchers tried to dig up every possible research study they could and only found a handful of studies testing the herbal remedy [1]. Six of those studies tested the effects of red raspberry leaf in a lab, with non-human or petri dish subjects (discussed below). Five studies took place in the clinic and actually considered humans with working human uteruses. Since that 2009 publication, only a few more studies (mostly in the lab) have trickled out.

(Note: finding only a few studies is not for lack of trying—the authors in the research round-up stretched so far as to include an obscure paper from 1941 that only included three women!)

The five clinical studies, looking at the safety and efficacy of red raspberry leaf use in pregnant humans, did not show any strong beneficial (or harmful) effects.

Some studies showed a shorter first or second stage of labor… but only by a few minutes. Only one study showed that it shortened the length of pregnancy… but only by a couple of days. Maybe that counts as inducing labor?

Weak evidence, yes. BUT, if shaving a few minutes off your labor and a few days off your pregnancy sound appealing (and I do not blame you if it does), there you go!

Yes… and no.

Overall, the laboratory studies show that raspberry leaf can facilitate more rhythmic contractions in uterine tissue. And rhythmic contractions are important for labor progress. However, some studies showed that the red raspberry leaf’s effects worked through toning and some showed that it worked through relaxing. Clearly, those two things are in direct conflict and are a scientific red flag, a reminder to take these studies with a grain of salt.

This red flag mainly calls into question study design. The laboratory studies use rodent uterine tissue and some of those rodents (mostly rats) are already dead long before the tissue is harvested and tested. Then, with their long dead or newly dead subjects, the researchers stick the isolated tissue into a petri dish and douse it in red raspberry leaf extract. This study design is not exactly equivalent to you drinking a cup of tea with your intact human uterus inside your human body housing a human baby.

Another lab study published after the review also directly tested how red raspberry leaf extract might stimulate uterine contractions in rodent uterine muscle, comparing pregnant to non-pregnant rats with some more promising results[2]. When rats were not pregnant, direct application of the extract to uterine tissue had no effect on uterine contractility. However, when the researchers tested a pregnant rat’s uterus, the muscle’s contraction response to raspberry leaf rivaled that of oxytocin. Oxytocin, as you may know, is the main hormone in charge of stimulating the uterus to contract.

Keep in mind, these studies are not studying you. They are studying a rodent uterus. Peeled into exposed muscle layers. Sitting in a petri dish. Doused in red raspberry leaf extract.

Not exactly a cup of tea.

Then the researchers went one step further and asked: does red raspberry leaf play the role of oxytocin’s little helper? Unfortunately, they had a crazy small study (six subjects!) and their results split right down the middle: half of the test subjects showed that oxytocin-induced contractions were strengthened with red raspberry leaf; the other half showed strengthening followed by immediate blockade of contractions. Not so helpful.

Building on that confusing finding, a more recent study looked closer at how exactly raspberry leaf works at the muscular level. In that study, the researchers doused rodent uterine muscle in increasing doses of raspberry leaf extract and found increasing responses of contraction activity. The response was similar to giving the muscle a classic stimulant. The effects of the extract in combination with different stimulants and relaxants also showed signs that red raspberry leaf contains a compound that might block a natural muscle relaxer. This action would enhance the ability of raspberry leaf to facilitate contractions [3].

So, yes, red raspberry leaf tea may have biological properties that stimulate the uterine muscle to contract. BUT, keep in mind, these studies are not studying you. They are studying a rodent uterus. Peeled into exposed muscle layers. Sitting in a petri dish. Doused in extract.

Not exactly a cup of tea.

But, is there a downside to drinking red raspberry leaf tea during pregnancy?

Well, fortunately, there were mostly no adverse effects noted. BUT, even one of the clinical researchers, a midwife who openly admitted to drinking copious amounts of red raspberry leaf tea during her pregnancies stated:

“After very well, term pregnancies, easy labours and births and two very healthy children, I am grateful that I knew about raspberry leaf. I would, however, discourage its use, until further studies can demonstrate its safety and efficacy.”

– Michele Simpson, midwife

With that said, the only study I could find that suggested a downside showed some potentially scary trans-generational effects[4]. That’s right, drinking raspberry leaf tea while pregnant may affect your baby and your baby’s baby. The babies of the mother rats used in the study showed signs of early puberty and the babies’ babies showed higher rates of growth restriction.

Before you get too freaked out about harming your baby’s baby, keep in mind that this study also requires the take it with a grain of salt advice. Just like the studies showing the benefits, this study also has some serious design flaws. In this study, mother rats were fed raspberry leaf extract every day from conception to weaning. Think about this in human use case terms— these rats were consuming raspberry leaf extract throughout the entire pregnancy. Are you? Most importantly, developmental effects that occur at the level of the baby’s baby need to happen very early in pregnancy, when the ovaries are developing. Are you drinking it that early?

Again, just like sussing out the benefits, more studies are also needed about the potential risks of red raspberry leaf consumption during pregnancy[5].

Conclusion?

Despite what the internet might have you believing, the jury is still out on the benefits of red raspberry leaf tea. In the words of one scientific buzzkill:

“The fact that the product has been in traditional use for decades does not constitute evidence”.

—L. Holst and colleagues

Basically, there are simply not enough good, quality, human-based studies to back up the claims that red raspberry leaf tea is a pregnancy super juice.

With that said, in honor of full disclosure, I must admit that I kept a a steaming pot of “Mother to Be Tea” next to me for pretty much the entire third trimester of my second pregnancy. I can’t say that the tea helped get my daughter out of my body any quicker (she was born 11 days after her due date) but my labor was short (less than six hours) so… maybe it worked?

REFERENCES

[1] Holst L, Haavik S, Nordeng H. Raspberry leaf – Should it be recommended to pregnant women? Complementary Therapies in Clinical Practice. 2009. pp. 204–208.

[2] Zheng J, Pistilli MJ, Holloway AC, Crankshaw DJ. The Effects of Commercial Preparations of Red Raspberry Leaf on the Contractility of the Rat’s Uterus In Vitro. Reproductive Sciences. 2010. pp. 494–501.

[3] Olson AE, DeGolier TF. Research Article: Contractile activity ofRubus idaeusextract on isolated mouse uterine strips. BIOS. 2016. pp. 39–47.

[4] Johnson JR, Makaji E, Ho S, Boya Xiong, Crankshaw DJ, Holloway AC. Effect of maternal raspberry leaf consumption in rats on pregnancy outcome and the fertility of the female offspring. Reprod Sci. 2009;16: 605–609.

[5] Simpson M, Parsons M, Greenwood J, Wade K. Raspberry leaf in pregnancy: its safety and efficacy in labor. J Midwifery Womens Health. 2001;46: 51–59.