Essential Oils to Avoid During Pregnancy

There is a lot of information out there about which essential oils to use and to avoid during pregnancy. Many different sites and aromatherapy books list essential oils to avoid during pregnancy, but unfortunately, much of this information is conflicting and unclear. Why does one list say a particular essential oil is okay, while another list says "avoid when pregnant?" Does the "avoid" mean internally or externally, too? The aim of this series of articles is to clear up the confusion and specify the particular risks involved with certain essential oils based on chemistry and toxicology data, and not just rumors and folklore.

Essential Oils Everyone Should Avoid At All Times, Internally and Externally
These essential oils contain dangerous compounds. Avoid them in aromatherapy, personal care products, and internally.

Cade (Contains Benzo[a]pyrene, a known carcinogen.)
Sassafras (Contains Safrole, a possible carcinogen.)
Ravensara anisata (Contains Estragole, a possible carcinogen.)
Basil (Contains Estragole, a possible carcinogen.)
Tarragon (Contains Estragole, a possible carcinogen.)
Camphor (Contains Safrole, a possible carcinogen, and contains Camphor [the compound] which is a neurotoxin and convulsant.)
Calamus (Contains Beta-asarone, a possible carcinogen.)
Tarragon (Contains Estragole and Methyleugenol, possible carcinogens.)
Snakeroot (Contains Methyleugenol, a possible carcinogen.)
Malaleuca bracteata (Contains Methyleugenol, a possible carcinogen.)
Bitter Almond (Contains Hydrocyanic acid, which is highly toxic.)
Armolse (Contains Thujone, a neurotoxin known to cause convulsions.)
Sweet Birch (Contains Methyl salicylate, which is highly toxic.)
Boldo (Contains Ascaridole, which is extremely toxic.)
Buchu (Contains Pulegone, which is toxic to the liver.)
Cassia (Contains Cinnamaldehyde, a liver toxin and skin sensitizer.)
Cinnamon Bark (Contains Cinnamaldehyde, a liver toxin and skin sensitizer.)
Costus (Contains Costuslactone, a strong skin sensitizer.)
Elecampane (Contains Alantalactone, a strong skin sensitizer.)
Horseradish (Contains Allyl isothicyanate, extremely toxic and irritating to skin and mucous membranes.)
Lanyana (Contains Thujone, a neurotoxin known to cause convulsions.)
Mustard (Allyl isothicyanate, extremely toxic and irritating to skin and mucous membranes.)
Pennyroyal (Contains Pulegone, which is toxic to the liver.)
Dalmatian Sage (Contains Thujone, a neurotoxin known to cause convulsions.)
Tansy (Contains Thujone, a neurotoxin known to cause convulsions.)
Thuja (Contains Thujone, a neurotoxin known to cause convulsions.)
Wintergreen (Contains high amounts of Methyl salicylate, which is highly toxic.)
Wormseed (Contains Ascaridole, which is extremely toxic.)
Wormwood (Contains Thujone, a neurotoxin known to cause convulsions.)

Essential Oils to Avoid During Pregnancy, Externally or Internally

Balsamite (Contains Camphor, a neurotoxin and convulsant.)
Ho leaf (Contains Camphor, a neurotoxin and convulsant.)
Hyssop (Contains Pinocamphone, which is generally toxic, a neurotoxin, and convulsant.)
Indian Dill Seed (Contains Apiol, which is generally toxic, an abortifacient, and toxic to the fetus.)
Juniperus Pfitzeriana (Contains Sabinyl acetate, known to be an abortifacient.)
Parsley Leaf (Contains Apiol, which is generally toxic, an abortifacient, and toxic to the fetus.)
Parsleyseed (Contains Apiol, which is a generally toxic, an abortifacient, and toxic to the fetus.)
Plectranthus (Contains Sabinyl acetate, known to be an abortifacient.)
Sage (Spanish) (Contains Sabinyl acetate, known to be an abortifacient.)
Savin (Contains Sabinyl acetate, known to be an abortifacient.)
Annual Wormwood (Contains Artemisia ketone, which is possibly toxic and a neurotoxin)
Cangerana (Contains Safrole, a possible carcinogen.)
Lavandula Stoechas (Contains Camphor which is a neurotoxin and convulsant.)
Lavender cotton (Contains Artemisia ketone, which is possibly toxic and a neurotoxin.)
Oakmoss (Contains Thujone, a neurotoxin known to cause convulsions.)
Perilla (Contains Perilla ketone, which is potentially toxic.)
Rue (Has a strong folk history of being an abortifacient with a small amount of clinical evidence to back it up. It is not known which compounds are to blame, but it is likely that its general toxicity is to blame for its possible abortifacient nature.)
Treemoss (Contains Thujone, a neurotoxin known to cause convulsions.)

Essential Oils that are Safe for External, but not Internal Use During Pregnancy
Anise (Contains Trans-anethole, which displays weakly estrogenic activity. The amount absorbed through skin when used in a cosmetic item would not affect hormonal levels, however, an oral dose could have an effect.)
Fennel (Also contains Trans-anethole.)
Lavandin (Contains a small amount of Camphor. The amount that would be absorbed through the skin in a personal care product is 500 times less than the amount needed to cause a deleterious effect, so it is considered safe for topical use, but it would be prudent to avoid an internal dose.)
Nutmeg and Mace (similar chemically) (Animal studies have proven no ill effects to the mother or fetus when applied externally. There is one case study of a pregnant woman who ate a high amount of nutmeg in a cookie; she and her baby started having heart palpitations. Everything returned to normal after 12 hours. It is thought that the stimulant effect of the Myristicin in the spice was to blame. The amount of Myristicin that would be absorbed through a properly diluted personal care product containing nutmeg or mace would not be great enough to cause this effect.)
Rosemary (Contains a small amount of Camphor. [See lavandin.])
Spike lavender (Contains a small amount of Camphor. [See lavandin.])
Yarrow (Contains a small amount of Camphor. [See lavandin.])

Your Questions Answered

I have heard that lemongrass is not safe during pregnancy. Is this true?
Rumors about Lemongrass being unsafe started with a study about citral, the main component of lemongrass essential oil. Doses of citral were injected in to lab rats, and the rats became less fertile at a dose of .3 g/kg. This is equivalent to injecting around 30 ml (2 tbs) of lemongrass essential oil in to the abdomen every 4-5 days for 60 days. Wearing a lotion or product with lemongrass in it doesn't provide the dose to see any side effect.

Are there any essential oils I should avoid when I'm trying to become pregnant?
Follow the same guidelines and lists that I've outlined above.

Are there any essential oils that help increase milk production during lactation?
No. There is no scientific data to suggest that any essential oil used externally would increase lactation.

What's the truth about Lavender & Tea Tree? Are they really estrogenic?
They are not! Check out my previous article on the subject.

Some lists say citrus oils should be avoided during pregnancy. Is this true?
There is no reason to avoid citrus oils during pregnancy. The only side effect of a citrus essential oil is that it if left on skin in a high concentration and then exposed to strong sunlight, it can increase sunburn or cause a rash. This reaction varies from person to person and depends on their own sensitivities.

What about ________ essential oil? I've read it should be avoided during pregnancy.
Everything but those on the lists above are safe to use for aromatherapy purposes (lotions, soaps, in diffusers, etc) during pregnancy. All essential oils are very powerful substances. Essential oils should always be diluted properly (.5% to 5% depending on the oil) in a carrier oil. Do not use undiluted on skin. Always consult a reputable healthcare provider, herbalist, or naturopath before using any essential oil internally.

If there is a particular essential oil you're concerned about, write it in the comments below and I'll be happy to give you an analysis!