Several popular teas carry real risks during pregnancy, from triggering uterine contractions to interfering with fetal development. The teas to avoid fall into two categories: herbal teas made from plants with known harmful effects, and caffeinated teas that can reduce birth size even at moderate intake levels. Here’s what to skip and why it matters.
Herbal Teas With the Highest Risk
Not all herbal teas are safer just because they’re caffeine-free. Some contain compounds that can stimulate contractions, alter hormone levels, or directly affect fetal development.
Licorice root tea is one of the most clearly harmful options. The active compound in licorice raises cortisol levels in the fetus, which can interfere with brain development. Finnish studies following children whose mothers consumed licorice during pregnancy found those kids scored lower on intelligence tests, had poorer memory, and had higher rates of attention and hyperactivity problems at ages 8 and 12. High intake was also linked to a more than twofold increased risk of preterm delivery. The Norwegian Scientific Committee for Food and Environment concluded that no safe level of licorice consumption during pregnancy can be established with certainty.
Hibiscus tea is another one to cut entirely. Animal studies have shown that hibiscus exposure during pregnancy altered offspring weight, delayed puberty, and changed hormone levels in breast milk. No human clinical trials have confirmed it’s safe during pregnancy or lactation, and its potential hormonal effects make it a poor choice when safer options exist.
Chamomile tea sounds harmless, but there’s evidence it can stimulate the uterus. Higher rates of preterm labor and miscarriage have been reported with regular use. A single cup occasionally may not pose a major threat, but drinking it daily or in large quantities is not recommended.
Other Herbs to Watch For
Several herbs commonly found in tea blends deserve caution:
- Stinging nettle: Found in many pregnancy tea blends and recommended by some midwives, but the Natural Medicines Database rates it as “likely unsafe.” The risk may depend on whether the root or leaves are used and in what quantity.
- Alfalfa: Rated “possibly unsafe” during pregnancy despite its vitamin content.
- Pennyroyal, mugwort, and blue cohosh: Known uterine stimulants that should be avoided completely.
The American Academy of Family Physicians specifically advises pregnant women to avoid teas containing chamomile, licorice, peppermint, or raspberry leaf, though the evidence on peppermint is less alarming than for the others. If you love peppermint tea, it’s worth discussing with your provider rather than assuming it’s off the table entirely.
Caffeinated Teas: Black, Green, and White
Black tea, green tea, and white tea all contain caffeine, and the old guideline of “stay under 200 milligrams a day” may not be cautious enough. A 2021 NIH study found that even mothers who consumed below 200 milligrams daily had babies with measurably reduced birth size and lean body mass. That’s roughly two cups of coffee or three to four cups of black tea.
Beyond caffeine, these teas contain tannins that dramatically reduce iron absorption. One cup of tea (about 200 ml) can cut iron absorption by 75 to 80 percent, with black tea showing the strongest effect. Since iron demands increase significantly during pregnancy and iron deficiency is already common, this is a meaningful concern. If you do drink caffeinated tea, having it between meals rather than with food helps minimize the impact on iron uptake.
Green tea gets a health halo, but during pregnancy it carries the same two problems: caffeine and tannins. A cup of green tea has roughly 30 to 50 milligrams of caffeine, so it adds up quickly if you’re drinking several cups alongside other caffeine sources like chocolate or soda.
Red Raspberry Leaf Tea Is Complicated
Red raspberry leaf tea is one of the most debated options. It’s marketed specifically for pregnancy, and many midwives recommend it to help tone the uterus before labor. But there is no uniform agreement on when it’s safe to start drinking it. Recommendations range wildly: some sources say one cup daily from the first trimester is fine, others say to wait until 36 or 37 weeks. The concern is that its uterus-toning properties could theoretically trigger contractions too early.
Most providers who do recommend it suggest waiting until at least the second trimester, and many prefer the third. If you’re interested in using it to prepare for labor, this is one to bring up at a prenatal visit rather than starting on your own in early pregnancy.
What You Can Drink Instead
Ginger tea is one of the best-supported options. The American Academy of Family Physicians lists teas containing ginger as “probably safe in moderation,” and ginger itself has solid evidence for easing nausea. Citrus peel, lemon balm, and rose hip teas also fall into this category.
Rooibos tea is naturally caffeine-free and doesn’t contain the tannins that block iron absorption, making it a practical swap for black tea drinkers. It’s not an herbal medicine; it’s simply a plant-based tea without the concerning compounds.
For any herbal tea, stick to commercially produced products rather than loose herbs from specialty shops, which can contain much higher concentrations of active compounds. The risk with herbal teas increases when they’re brewed strong, consumed in large amounts, or made from herbs that haven’t been standardized for safety. One to two cups a day of a commercially produced, pregnancy-safe herbal tea is a reasonable guideline, while treating anything unfamiliar or highly concentrated with skepticism.