fennel seeds scattered across blue background

Fennel Seeds in Pregnancy: Are They Safe?

You’ve heard that fennel can provide a host of potential health benefits, from aiding in digestion to possibly increasing milk supply.

You’re curious if fennel seeds in pregnancy may help manage some of your symptoms. But you also aren’t sure if it’s safe.

Most health professionals advise against the use of herbs and supplements during pregnancy out of an abundance of caution. 

You want to keep baby safe, but also want to know what research actually shows regarding the use of fennel seeds in pregnancy.

We completely understand! You deserve to have the knowledge to make an informed choice regarding the health of yourself and your baby.

In this article, we will describe traditional uses for fennel, what research shows regarding the use of fennel seeds in pregnancy, and our conclusion about the safety of saunf in pregnancy.

Let’s get started!

What Is Fennel?

Fennel, also known as saunf, is a bulb vegetable common in Italian dishes. If you’re not familiar with fennel, it has a slightly sweet licorice flavor and looks a little like an onion. And you can eat all parts of the plant. 

Types of Fennel

Fennel Seeds

If the fennel continues to grow and flower, it produces seeds that can be eaten. These are commonly the seeds that you see in salami or sausage. 

Fennel Powder

You may see fennel powder being sold at the store. Fennel powder is usually just ground fennel seeds that are used either for cooking or for medicinal purposes. 

Fennel Tea

Fennel tea is sold both as a loose leaf tea and in pre-packaged tea bags. This tea is most often made from fennel seeds, but may sometimes be made from the dried fruit or leaves.

Fennel Bulb

Fennel bulbs can be eaten both raw and cooked. Raw fennel is crunchy and sweet, whereas cooked fennel becomes soft and can provide a mild anise flavor to dishes. 

What are fennel seeds good for? 

Fennel has been used for medicinal purposes for centuries. 

There are many health claims around fennel seeds, including reduced bloating, improved digestion, improved heart health, and lactation support. 

So what does the research actually show?

Fennel seeds are nutritious.

Fennel seeds contain calcium, potassium, magnesium, phosphorus, and fiber. 

According to the USDA, 1 tablespoon of fennel seeds contains: 

  • 70mg calcium
  • 98mg potassium
  • 22mg magnesium
  • 28mg phosphorus
  • 8 IU vitamin A
  • 2 grams fiber

Fennel may help reduce IBS symptoms.

Fennel could be a complementary or alternative treatment option for individuals with irritable bowel syndrome (IBS).

One study showed that people with IBS who were given fennel essential oil saw improvements in bloating, bowel habits, and quality of life when compared to a placebo. 

Fennel may help protect your liver.

This study showed that fennel essential oil decreased liver damage in rats. This was seen by improvements in their liver labs. However, more human research needs to be conducted to learn more. 

Fennel may have some cancer-fighting components.

There have been some studies that indicate that fennel may help fight against some cancers in some people. 

It is important to note that cancer is a very complex condition that requires individualized care and treatment. These studies were conducted on cancer cells in a lab or in animal subjects, so more research needs to be done to understand how fennel affects different types of breast cancer in humans. 

Fennel may help milk production in breastfeeding women. 

This is one of the better known claims about fennel. 

There is some evidence that fennel may help boost milk supply. It is suspected that this effect may be due to some specific comapounds in fennel that may increase prolactin levels.

Prolactin is the hormone that our bodies naturally makes to create breastmilk. Therefore, if prolactin levels increase, milk production may follow. 

However, other studies have not found a relationship between fennel and milk supply. Some have even found that fennel can lead to difficulties with feeding and reduced weight gain.

It is important to note that anethole, a component of fennel, can be transferred from breastmilk to the baby. 

We found two reported cases of toxicity in infants that were connected to fennel tea. Both mothers were drinking 2 liters of herbal tea per day containing an herbal blend. 

While anethole amounts were not measured, symptoms in both babies improved 1-3 days after they stopped breastfeeding and stopped drinking the tea. 

Amounts of anethole were not measured in the breastmilk, but the symptoms were thought to be caused by the anethole found in fennel and anise. 

Always talk to your healthcare provider before taking fennel to help with breastmilk production. 

Is it OK to drink fennel tea every day? 

Fennel is thought to be a phytoestrogen, meaning that it can impact your body’s reproductive hormones. 

This is not necessarily a bad thing but could be risky for people who are pregnant or at risk for estrogen-sensitive cancers. 

Talk to your doctor to see if fennel tea is safe for you to drink regularly. 

Fennel Seeds in Pregnancy

How does fennel affect reproductive hormones?

Fennel is often used to help regulate menstrual cycles and other women’s health conditions. 

One study found that taking a fennel infusion along with dry cupping helped reduce the amount of time between periods in women with PCOS. 

Several small studies have also indicated that fennel may help reduce menopause symptoms. 

Potential Risks of Fennel Seeds in Pregnancy

First, let’s talk about experimental studies during pregnancy.

It’s not ethical to conduct research on pregnant women when there is any possibility that it could harm the mother or baby. We have randomized control trials for several medications and supplements, but they often exclude pregnant women for this reason.

Therefore, much of the research below is based on animal models or test tube studies. This is the best we can do for actual experimental models. 

As far as pregnancy research goes, the only other option is observational research. This is where we would study women who have already taken these substances and observe what happened.

That’s why there’s always so much caution issued for pregnant women regarding any substances. We just are very limited in ways to conduct good research on the safety and effectiveness of these substances. 

Always, always, always talk to your healthcare provider before starting ANY medications or supplements when pregnant, trying to become pregnant, or breastfeeding. 

Okay, now that we have that out of the way, let’s look at the safety of fennel during pregnancy. 

Fennel seeds during pregnancy first trimester

There is a lot happening during the first trimester of pregnancy. Even though your baby is only 1-1.5 inches long, pretty much all of their organs and organ systems have already been formed.

The baby is also more susceptible to substances, including medications, during this time.

For this reason, it is not recommended to eat fennel seeds during pregnancy first trimester. 

Fennel seeds during pregnancy second trimester

During the second trimester, babies continue to grow in size and development. They will begin to respond to stimuli and develop their swallowing and sucking reflexes (among many other things!). 

Generally speaking, babies born around 24 weeks may survive in the ICU. 

Given that there is some evidence that fennel may stimulate uterine contractions, it could result in miscarriage or preterm birth. 

Therefore, it is not recommended to eat fennel seeds during pregnancy second trimester. 

Fennel seeds during pregnancy third trimester

Just like with the 2nd trimester, there is a chance that fennel could cause your uterus to contract, resulting in preterm birth. 

Therefore, it is not recommended to eat fennel seeds during pregnancy third trimester. 

How much is Safe?

No safe amount of fennel in pregnancy has been determined. 

Final Thoughts: is fennel safe during pregnancy?

The general consensus is that it is likely safe to eat the amount of fennel seeds in pregnancy that would be normally found in foods.

However, larger doses of fennel in any form could increase the risk of miscarriage and preterm birth. Therefore, fennel powder, fennel tea, and fennel essential oils are likely not safe during pregnancy.

So, if fennel is listed as an ingredient in a favorite food, it is likely fine to go ahead and eat it. But amounts used in medicinal forms are likely not safe.

Research on fennel seeds in pregnancy is limited. 

But given the potential risks, it is not recommended to eat fennel seeds during pregnancy. 

Interested in learning more about pregnancy nutrition?

Check out this article about superfoods for pregnancy and this article about healthy breakfast ideas during pregnancy!

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