Small amounts of anise in pregnancy can be safe, but patients should avoid anise essential oil and other concentrates. Patients with high-risk pregnancies also may be advised to avoid anise altogether to reduce the chances of going into premature labor. It is also important for people to be aware that anise (Pimpinella anisum) and star anise (Illicium verum), sometimes also called Chinese star anise, are two different herbs that should be handled differently. Chinese star anise comes with some additional risks.
Anise is a food ingredient used in a variety of things to add a slightly licorice-like flavor. It’s common in sweets and can also be used in main courses to make the taste more complex and interesting. Plain anise seeds as used in small amounts in herbal teas and cooking are generally safe in pregnancy and breastfeeding because exposure is relatively low. Essential oil and concentrates, however, are more dangerous, and should be avoided because of concerns that they might trigger contractions.
Patients who use anise in pregnancy could develop uterine stimulation which might cause early labor. This could result in pregnancy loss in the early stages of the pregnancy, and might cause complications for more progressed pregnancies. Premature birth carries a number of risks for both mother and child, and should be prevented if possible. Avoiding concentrated anise while pregnant, along with other herbs known to promote contractions, is advisable.
With Chinese star anise, there is cause for additional concern. Some sources of this herb use a related product, Japanese star anise, that is actually toxic and not safe for either culinary or medicinal use. If patients do not have a pure source of the herb, they could be at risk of exposure to the more toxic form, which could cause illness and complicate the pregnancy. For safety reasons, it can be advisable to avoid Chinese star anise in pregnancy, unless a source is known and verified as safe.
Any questions about the use of food ingredients and herbal preparations in pregnancy can be discussed with an obstetrician. Much of the research on these subjects is incomplete because it is difficult to perform clinical trials without running into ethical problems, since scientists don’t want to endanger expecting mothers and their babies. Regulatory agencies may indicate that anise in pregnancy is of unknown safety, reflecting a general lack of data. An individual health care provider might have opinions for a patient based on experience or medical history.