Medicinal Mushrooms Before, During, and After Pregnancy - Safety, and What Works

What we know

Mushrooms are more readily accessible as supplements to the general public than ever before in the Western world, and carry a reputation of safety during pregnancy. Indeed, the safety of mushrooms as a food source during pregnancy is seldom disputed unless there is concern around accurate identification of the mushroom itself. You won’t find culinary mushrooms on any cautionary pregnancy food lists, because well-cooked mushrooms are widely recognized as a healthy addition to a diet rooted in whole foods—regardless of one's pregnancy status.

As drying, extracting, and encapsulating mushrooms for consumption in more concentrated doses grows in popularity, so does speculation — how safe is it to consume these extracts during pregnancy? Unlike their counterparts maitake, lion’s mane, shiitake, and oyster mushrooms, many medicinal mushrooms such as reishi, turkey tail, and chaga are too fibrous for typical culinary use. This lands them more definitively in the medicinal category than the food category and, as a result, prompts questions regarding their safety before, during, and after pregnancy.

Mushrooms as Food

Numerous “danger” lists outline what to avoid during pregnancy, often more fear-driven than fact-based, and you won’t find mushrooms on any of these lists. Medicinal mushrooms that are also commonly consumed as food—maitake, lion’s mane, shiitake, and oyster—are not just safe but also highly nutritious, and incorporating them into your daily diet throughout pregnancy should not pose any concerns.

Mushrooms as Medicine

It’s easier to get a higher dose of bioactive compounds when mushrooms are extracted and encapsulated, begging the key question of this guide: are mushrooms still safe during pregnancy when taken as extracted supplements?

Here is a review of the most relevant research as well as traditional use of mushrooms from the prenatal to postpartum periods.

Prenatal support

Prenatal support usually has the intention of improving ovulation, regulating hormones, managing stress and ensuring proper nutrition. Mushrooms may be one of the most important foods to consume on the journey to pregnancy - but what about supplements?

Reishi, maitake, and oyster mushroom for prenatal support

Maitake

A small clinical trial from 2010 provided women with PCOS capsules containing 200mg maitake powder, in addition to 18mg of concentrated MSX (a patented maitake extract from Mushroom Wisdom Inc.) (1). Taken as 3 tablets 3 times daily for a total dose of 1,800 mg maitake and 162 mg MSX, participants improved ovulation to a similar degree as the drug clomiphene citrate, a typical treatment for ovulation induction in PCOS. The ovulation rate with clomiphene in this trial was 93.5% compared to an ovulation rate with maitake supplementation of 76.9%. Some women in the study did not ovulate with maitake or clomiphene alone, and when the two were combined, ovulation rates in that population increased significantly.

This trial suggests that maitake supplementation is similarly effective as clomiphene at fertility enhancement in patients with ovulatory dysfunction, and may be effective for people trying to conceive.

Reishi

Reishi mushroom has been used traditionally for thousands of years to help calm the spirit, or in modern Western terms, support a healthy stress response. During the prenatal period, this may be one of the most important aspects of ovulation and conception. Reishi, when given at doses of 2g daily, can help to regulate levels of the stress hormone cortisol (2). When subjected to stress on a daily basis over a long period of time, people may produce too much or too little cortisol, and this cortisol dysregulation can impact sex hormone production, impacting fertility (3,4).

Reishi also regulates excess androgen (testosterone) levels, which can impact fertility in women. In a study exploring the anti-androgenic effects of 20 species of mushrooms, reishi had the strongest effect via reduction in the enzyme 5-ɑ reductase, responsible for the conversion of testosterone to dihydrotestosterone, the more biologically active androgen (5).

This research suggests that reishi is helpful in the prenatal period for improving sex hormone function by supporting cortisol regulation and the inhibition of 5-ɑ-reductase.

Ergothioneine

The amino acid ergothioneine, commonly found in mushrooms, could theoretically be very beneficial during the prenatal period. Ergothioneine is a compound ubiquitous in mushrooms and algae, and is found in especially high concentrations in oyster mushrooms. Humans have a very specific transporter for ergothioneine in cells that are more susceptible to oxidative stress/damage, and ergothioneine builds up as an antioxidant within cells. It has been postulated that this may be useful as a prenatal supplement to establish an antioxidant reserve to prevent/protect against preeclampsia later in pregnancy. In one observational study, women who had a higher concentration of ergothioneine in their plasma were less likely to develop preeclampsia - more on that below (6).

Mushrooms during pregnancy

Mushrooms are not only safe to consume as food during pregnancy, but may actually be helpful in preventing pregnancy-related disease. It is, however, difficult to study herbs and other supplements in human pregnancy, so there is generally very little data on most supplements and natural compounds. Because of this, to be on the safest side possible, it is generally not recommended to take compounds during pregnancy with unknown safety profiles.

Eat your mushrooms

In a randomized clinical trial, subjects consumed 100g of cooked white button mushrooms daily in addition to their normal diet from pre-pregnancy until the 20th week of gestation. Compared to the placebo group, the “mushroom diet” group had a significantly reduced incidence of gestational hypertension, preeclampsia, excessive gestational weight gain and gestational diabetes, suggesting that mushrooms are an essential ingredient in diets during pregnancy (7).

Reishi babies?

Other than this clinical trial, studies exploring mushroom intake in human pregnancy are sparse. There are tales of women throughout Asia taking reishi during pregnancy and giving birth to very calm, zen-like children, AKA “reishi babies”. While I love this idea, and the adaptogenic and HPA-axis-regulating actions of reishi suggest plausibility, I could not find any actual evidence of the practice or the outcome.

Medicinal mushrooms

While human evidence for mushroom consumption during pregnancy is sparse, there are a number of rodent studies indicating not only safety, but therapeutic value.

Shiitake - safe in pregnancy

Shiitake mushroom is a nutritious and widely-consumed food, and I have no doubt that it is safe to consume in pregnancy as a “functional” food. There are a few studies in mice and rats exemplifying this.

In one rat study, shiitake mushrooms were fed to rats who had induced gestational diabetes. Shiitake was given early in pregnancy, and there was a decrease in preimplantation pregnancy loss compared with the control group. Shiitake had a protective effect on preimplantation parameters, though it was not able to reverse gestational diabetes throughout the pregnancy (8).

In another rat study, consumption of shiitake reduced triglyceride levels and proved no changes in maternal weight and reproductive capacity. There were no morphological changes in the fetuses’ body measurement, suggesting it is likely safe to ingest throughout pregnancy (9).

Reishi

Another study on pregnant rats with induced diabetes explored the effects of reishi mushroom on the glycemic response in the oral glucose tolerance test as well as other values including liver function studies and lipid peroxidation. Reishi reduced the glycemic response in the glucose tolerance test, decreased liver enzymes, and decreased lipid peroxidation. Levels of important antioxidant enzymes, catalase and glutathione peroxidase, are decreased in gestational diabetes, and these levels were improved with reishi administration. In addition to improved blood markers, measurements of the fetal head and thorax were greater in the rats exposed to reishi, indicating healthier fetal body sizes in the reishi group (10).

Note

Studies on medicinal mushrooms throughout pregnancy are very limited and because of this they are generally considered unsafe unless they are also a food mushroom like lion’s mane, maitake, shiitake, oyster, enoki, etc. These food mushrooms, or functional foods, are not only safe during pregnancy but may help to prevent pregnancy complications like preeclampsia and gestational diabetes.

Ergothioneine for preeclampsia

I mentioned earlier that ergothioneine is a highly bioavailable amino acid found in mushrooms that accumulates in organs susceptible to higher levels of oxidative stress, like the endothelial cells lining our blood vessels (11). Preeclampsia, a pregnancy-specific clinical syndrome which involves new-onset hypertension (high blood pressure) plus new onset proteinuria (protein in the urine), is associated with oxidative stress and endothelial cell dysfunction (12). The study mentioned above demonstrated that women with the highest plasma concentration of ergothioneine were less likely to develop preeclampsia. Although there is much more investigation to be done, it is likely that ergothioneine intake in the prenatal period and during pregnancy could help protect against preeclampsia (13).

Ergothioneine - safe in pregnancy

In a rodent study exploring the reproductive safety of ergothioneine, no adverse or toxic effects were noted, and ergothioneine was considered to be well-tolerated and without adverse effects in any of the reproductive parameters evaluated (14). Since this study, the European Food Safety Authority concluded that synthetic L-ergothioneine is safe for infants, young children, and pregnant and breastfeeding women in the following amounts (in addition to background diet): 2.82 mg/kg body weight per day for infants, 3.39 mg/kg body weight per day for toddlers and 1.31 mg/kg body weight per day for adults including pregnant and breastfeeding women (15).

Postpartum Support

For many, postpartum is a complicated time full of deep love, exhaustion, and overwhelm. Medicinal mushrooms can be extremely helpful during this time for keeping the immune system strong, supporting a healthy nervous system, and possibly even helping with milk production.

Mushrooms and breastfeeding

The most-studied medicinal constituents in mushrooms are β-glucans, AKA polysaccharides. It is well known that the main mechanism of immune-modulation from mushrooms is via the relationship between 1,3-1,6-β-glucans binding to dectin-1 receptors within the gut associated lymphoid tissue (GALT) within the intestines. Dectin-1 receptors are found elsewhere in the body as well, including the pituitary gland which plays a major role in hormone production and regulation throughout the body. The pituitary gland is also where prolactin, the hormone that stimulates breast milk production, is made.

One study found that β-glucans stimulated prolactin production via dectin-1 receptors (16). β-glucans researched in this study are 1,4-β-glucans, which are found in oats, barley and other grains but based on the mechanism of action and interaction with dectin-1, it is likely that fungal β-glucans would have a similar effect.

Reishi and cordyceps for recovery

In addition to having a potentially positive effect on breast milk production, taking mushrooms while breastfeeding also helps to support the immune system and nervous system of the breastfeeding parent, which is vital after birth. Reishi may be an essential mushroom in the postpartum period to help with sleep, anxiety, cortisol regulation, and immune support.

The combination of reishi and cordyceps could help to maintain energy and regulate the nervous system when there is significant sleep deprivation (17). Mushroom extracts, taken internally and used topically, are also beneficial in all phases of wound healing and may be a helpful addition in bone broths and soups to support tissue repair after vaginal birth and C-section (18). It is important to note that reishi does have mild anti-platelet activity, meaning that it can interfere with blood clotting (19). Reishi is a good option after all bleeding has stopped and if taken prior to birth, discontinue one week before vaginal delivery and C-section.

Lion’s mane for cognitive support

Besides being rich in β-glucans, which may help with breast milk production, lion’s mane may also help with postpartum “mommy brain”. Sleep deprivation, focused attention on a newborn and hormone shifts leave little room for other mental responsibilities. While reishi can help with stress and sleep and cordyceps can help with energy, lion’s mane is likely the most helpful for cognitive support during this time for memory, anxiety and depression. After birth, once the placenta comes out, sex hormones estradiol and progesterone are quite similar to the low levels found in those going through perimenopause, and this hormone shift contributes to mood changes (21). Lion’s mane has been specifically studied in the menopausal population and significant benefit was seen in memory, anxiety and depression dosed at 2g daily suggesting a similar benefit during the postpartum period (22).

Our central question: mushroom safety

I have reiterated throughout this guide that mushrooms traditionally eaten as food are safe as food before, during, and after pregnancy. The safety of medicinal mushrooms taken as extracts, however, will remain up for debate. Safety considerations rest on the question of what, specifically, we are concerned about with herbs and supplements surrounding pregnancy, and these concerns are mostly related to clotting issues, the potential for miscarriage via various mechanisms, and interference with fetal development (teratogenicity).

No medicinal mushrooms, including those discussed in this guide, have medicinal properties or actions that are of concern for any of these potential safety issues. It is, and will be, however, impossible to definitely describe them as safe due to the inherent limitations of studying safety in pregnant people in real life. We are constrained by the limits of our epistemology, and rely instead on triangulating reasonable conclusions based on the evidence at hand.

Risks to pregnancy and fetal development abound in the first trimester, and it is recommended to avoid all products and exposures that have unknown potential consequences during this time. During the second and third trimesters, concerns for fetal development and miscarriage diminish, and it becomes more reasonable to expand your horizons. Precautions taken by pregnant parents are often highly individual, and based on the personal weighing and balancing of potential risks and benefits. I hope this guide has provided enough additional context and information to make more informed decisions, while recognizing the limits of what we do, and can, know.

Closing Thoughts

Fungi are the doulas of nature. They play an essential role in transformation - in death, decay, and rebirth. It is important to not only consider the biochemical mechanisms and clinical research when it comes to using once living organisms as medicine, but to think about and understand the role they play in the natural world and how that role reflects how they act energetically when consumed as medicine. When thinking about mushrooms in this way, there is no doubt that they would be allies throughout gestation, and especially postpartum.

-Appendix-

Mushroom safety chart

	Prenatal	1st Trimester	2nd Trimester	3rd Trimester	Breastfeeding (postpartum)	Not breastfeeding (postpartum)
Reishi	Safe	Unknown	Likely safe	Likely safe	Likely safe	Safe
Maitake	Safe	Safe as food	Safe	Safe	Safe	Safe
Turkey tail	Safe	Unknown	Likely safe	Likely safe	Likely safe	Safe
Oyster	Safe	Safe as food	Likely safe	Likely safe	Safe	Safe
Lion's mane	Safe	Safe as food	Likely safe	Likely safe	Likely safe	Safe
Cordyceps	Safe	Unknown	Likely safe	Likely safe	Likely safe	Safe
Tremella	Safe	Unknown	Likely safe	Likely safe	Likely safe	Safe
Shiitake	Safe	Safe as food	Safe	Safe	Safe	Safe
Chaga	Safe	Unknown	Unknown	Unknown	Unknown	Safe
Ergothioneine	Safe	Safe	Safe	Safe	Safe	Safe

Summary of potential benefits before, during, and after pregnancy

Prenatal

Maitake - Ovulation support

Reishi - Decreases androgens and regulates stress hormones

Ergothioneine - Antioxidant support, preeclampsia prevention

Pregnancy

Shiitake - Immune support, ergothioneine benefits

Oyster - Ergothioneine benefits

Maitake - Immune support

Ergothioneine - Antioxidant support, preeclampsia prevention

Postpartum

Reishi - Stress, sleep, benefits of β-glucans

Cordyceps - Energy, benefits of β glucans

Lion’s mane - Memory, anxiety, depression, benefits of β-glucans

Turkey tail - Benefits of β-glucans

Tremella - Benefits of β-glucans

Maitake - Benefits of β-glucans

Oyster - Benefits of β-glucans

Shiitake - Benefits of β-glucans

β-glucans - Breast milk production, immune support, microbiome support, blood sugar regulation, wound healing

***Disclaimer: There is really not enough clinical safety information on the use of mushroom supplements throughout pregnancy and breastfeeding to be certain that they are all safe during this time. Based on what I have gathered from the research and historical use, they are likely safe, but of course, ask your midwife and or ObGyn about what would be right for you specifically. This article is intended for information purposes only.

References

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