I found it very difficult to put a list together of oils to avoid during pregnancy. As I searched various sources, I found that each author held his own opinion, and depending on his frame of reference, the list changed.

Carrying an unborn child is an incredible responsibility, and we strongly recommend that you only use pure, high quality oils and use them in moderation. Many long-time essential oil users feel that high quality oils that are diluted, applied topically and in moderation should not cause a problem. An unsafe oil is one that is not pure and has possibly been distilled with chemicals at high heat for high yield rather than for therapeutic value. Using any oil improperly or outside the realm of moderation may be unsafe.

This list is compiled from various sources: Ann Berwick, Connie & Alan Higley, Julia Lawless, Shirley & Len Price, Jeanne Rose, Robert Tisserand and Tony Balacs.

Single Oils: Basil, Birch, Calamus, Cassia, Cinnamon Bark, Hyssop, Idaho Tansy, Lavandin, Rosemary Cineol, Sage, Tarragon, Wintergreen

Single Oils: Angelica, Cedarwood, Cistus, Citronella, Clary Sage, Clove, Cumin, Cypress (Black), Davana, Fennel, German Chamomile, Laurel Nobilis, Marjoram, Mountain Savory, Myrrh, Nutmeg, Peppermint, Rose, Spearmint, Vetiver, Yarrow

Clary Sage, Sage and Fennel contain constituents with hormone-like properties that could possibly cause adverse reactions in the mother, although, according to Higley's, there are no recorded cases in humans.

German Chamomile
Grapefruit
Jasmine
Lavender
Mandarin
Roman Chamomile
Rose
Spearmint
Tangerine
Ylang Ylang

Mother's Moisturizing Spray or Lavender: Use as a massage on location, or add a few drops to ½-cup Epsom salts and mix in bath water.

Circulation Blend + Lavender. Apply over the heart, on the feet, on the lifeline of the hand and under the ring finger and above the elbow. It may also help to apply this blend along the spine from the first to the fourth thoracic vertebrae, which correspond to the cardiopulmonary nerves. Diffuse Ylang Ylang during labor if high blood pressure is an issue.

Increase intake of magnesium, which acts as a smooth-muscle relaxant and as a natural calcium channel blocker for the heart, lowering blood pressure and dilating the heart blood vessels.

Avoid using Hyssop, Rosemary, Sage, Thyme and possibly Peppermint.

Citrus Blessing + Lavender. Dilute with massage oil and apply to breasts and under arms twice a day. (Apply after nursing and avoid the nipple area.)

Lymphatic Cleanse in drinking water may help drain the lymph system and keep the toxins flowing out of the body.

Ancient Healing and Warrior blends are powerful infection fighting oils. Diffuse, rub on the bottoms of the feet or take internally (3 drops in a capsule) to help fight infection.

Peppermint oil applied at the head. Baby will usually turn away from the oil.

Digestion Support blend. (Apply topically on abdomen or add a drop or two to a glass - not plastic - of water several times a day as needed.)

Clary Sage has been used to tone the uterus and has been known to speed up slow labor or strengthen ineffectual contractions. Apply Clary Sage around the ankles. This can be very effective taken internally (about 6 drops under the tongue and held there up to two minutes or in a capsule.

Clary Sage, Lavender, Mother's Moisturizing Spray (stimulates circulation, calming, antibiotic-like, anti-inflammatory, antiseptic)

Nutmeg (adrenal support, balances hormones, calms the central nervous system, alleviates anxiety, increases circulation and is good for blood supply). Nutmeg is generally non-toxic, non-irritating and non-sensitizing. However, large doses may cause nausea, stupor and tachycardia. Use in moderation and with care during pregnancy.

Bones & Joints blend – May help to align mother's hips; apply along the inside and bottom of each foot, then have someone hold feet – right palm to right foot and left palm to left foot (to balance energy flow). Rub a couple drops along the newborn's spine for alignment.

3 drops Ginger, 2 drops Cypress and 2 drops Lavender mixed with 2 tablespoons vegetable oil massaged on location (not the abdomen), always massaging upward toward the heart. Use once a day as needed for up to 10 days, and then give your body a break.

Mother's Moisturizing Spray massage. Diffuse Lemon. Blend equal amounts of Lavender, Grapefruit and Coriander. Mix 6 drops with Epsom or bath salts, and enjoy!

Drink about 80 oz. water daily. The general rule of thumb is ½ your body weight in ounces of pure water a day.

Add a few drops of Helichrysum or Helichrysum Blend to Mother's Moisturizing Spray and apply to lower back to help prevent hemorrhaging.

Apply Hemorrhoid Care blend topically. A very diluted mixture of Myrtle, Cypress, Basil, Helichrysum (Blend and, Peppermint essential oils mixed with a lubricating carrier oils such as Almond, Emu or Olive works very well. We use a 1:7 ratio of essential oil blend to the carrier oil.

Mother's Moisturizing Spray or Lavender & Ylang Ylang applied topically.

Clary Sage and Tapestry blend may help kick labor into gear and may be combined with Fennel.

Mother's Moisturizing Spray rubbed on little fingers and toes when contracting may help keep the baby in the birth canal.

Diffuse Lavender during labor. Lavender has analgesic and antiseptic-like properties. Lavender is soothing and stimulates circulation.

8 drops Clary Sage, 8 drops Lavender, 8 drops Jasmine in 2 oz. massage oil may be useful when trying to induce labor or augment a slow, lazy labor.

Mother's Moisturizing Spray or Lavender & Geranium
Lavender is calming and has a slight analgesic effect. It also stimulates circulation, which is great for both mother and baby, and has anti-inflammatory and antiseptic properties. Geranium is one of the best oils to stimulate circulation, which in turn facilitates easy breathing. It has a contractive effect and helps pull together dilated tissues, so it is healing for the uterus and endometrium after the birth.
Gently massage any of these oils on lower abdomen.

Prepare a foot bath with comfortably hot water and add: 10 drops Lavender, 5 drops Geranium and 2 drops Cypress

To relieve pressure and decongest add a few drops of Mother's Moisturizing Spray to a bowl of warm water. Soak a washcloth in this solution and apply to breasts as a compress. (See Breast Infection)

Clary Sage (brings in milk), Fennel or Basil (increase), Peppermint with cold compress (to decrease). Dilute with massage oil and apply after nursing and avoid the nipple area.

 ***Caution: According to Higley's, Fennel should not be used for more than 10 days as it will excessively increase flow through the urinary tract.

Lavender may help prevent a miscarriage.

After a miscarriage massage abdomen with Mother's Moisturizing Spray, Frankincense, Geranium, Grapefruit, Lavender, Roman Chamomile or Spruce topically midway between the navel and base of the sternum.

May be caused by a congested liver. If possible, do a colon and then liver cleanse before conception. Digestion Support blend (1-2 drops in a glass (not plastic) of water and sip or apply 1-2 drops around the navel, apply on or behind the ears) Ginger or Peppermint may also be used. Diffuse Lemon or Spearmint.  A few drops of Grapefruit, Lemon, Tangerine or Orange essential oil in water sipped throughout the day should help. Adequate water consumption will help move the toxins out. Spirulina, barley grass juice and kelp supplements may help also.

Myrrh on remaining umbilical cord and around the navel to protect from infection.

Nursing Care blend of true Rose (Rosa damascena) and Marigold (Calendula officinalis) in a base of Almond, Tamanu/Foraha ( or Calophyllum) oil and Wheat Germ oils is very healing to sore and cracked nipples. Calendula tincture helps heal cracked, bleeding nipples also..)

The following oils used individually may increase milk supply. These oils can be applied topically to breasts, but be sure to dilute with massage oil. Apply after nursing and avoid the nipple area, or add a drop or two to a glass of water several times a day as needed.
Clary Sage
Fennel
Geranium

Use the following oils sparingly as they may decrease milk supply.
Melissa
Oregano
Peppermint
Sage Dalmation (Officinalis)
Spearmint
Thyme
Yarrow

Pain-X (Apply to lower back and tummy area as desired.)

Basil has been used to help retain, and Jasmine helps expulsion.

Geranium and Helichrysum Blend applied on placental site may help stop bleeding after a placental abruption.

Lavender rubbed on tummy may help stop premature labor.

Testimony
1. I have used LAVENDER for years to soothe monthly cramps with great success, so when I went into premature labor with contractions and bleeding at 16 weeks, I immediately reached for my Lavender.

I mixed a few drops of lavender in about a teaspoon of virgin coconut oil and applied it directly on my abdomen and prayed for the Lord to use His oil to stop the contractions. The first application seemed to have no effect, so after an hour, I did it again, and the bleeding and contractions slowed way down. I kept doing it through the day and a few times in the night. Within 24 hours the bleeding and contractions had completely stopped.

I continued using lavender on my belly morning and evening. Not only was this soothing and relaxing for me, my OB was still very concerned about a premature birth. Many prayers were said on my behalf, and I was careful to hang out on the couch or recliner for about a month, but I never had another problem with premature labor or bleeding. Our sweet little daughter was born right on time, and she's the calmest baby I've had yet. I have to wonder if all that lavender had some calming affect on her as well as me. Another bonus to my daily massages with lavender and the coconut oil is that I can't find a single stretch mark.

Mother's Moisturizing Spray (apply to tummy daily).

Apply Tender Tissue Spray to perineum 3 weeks before delivery, 3 times a day. (Mother's Moisturizing Spray, Lavender or Geranium work well too.) Tender Tissue Spray is anti-fungal and will also help avoid vaginal yeast infection.

Circulation Blend. Apply over the heart, on the feet, on the lifeline of the hand and under the ring finger and above the elbow. It may also help to apply this blend along the spine from the first to the fourth thoracic vertebrae, which correspond to the cardiopulmonary nerves.

Massage swollen ankles and legs with equal amounts of Cypress, Lavender and Ginger (6 drops of this blend mixed with 2 tablespoons vegetable oil.

For prevention, make sure mom consumes dark, leafy greens daily to help assimilate protein.

Myrrh on remaining umbilical cord and around the navel to protect from infection.

Blood Clot Aid or add 5 drops each of Cypress, Lemon & Geranium to 2 oz. unscented lotion and apply over troublesome veins. It is not recommend to massage the veins.

Tender Tissue Spray applied topically on location as needed. Some have had quick results fighting the candida by taking Cleansing blend internally.