CBD & Contraceptives

What are Contraceptives

Contraceptives also called birth control, is the most commonly prescribed form of contraception in the US. Approximately 25% of women age 15 to 44 who currently use contraception reported using the pill as their method of choice.

As the name suggests, birth control is primarily used to prevent pregnancy. In hormone-based contraceptives, progesterone is the hormone that prevents pregnancy, while estrogen will control menstrual bleeding. The primary mechanism of action of progesterone to prevent ovulation by inhibiting follicular development and preventing ovulation. Another primary mechanism of action is progesterone’s ability to inhibit sperm from penetrating through the cervix and upper genital tract by making the cervical mucous unfriendly.

Estrogen also has some effect in inhibiting follicular development because of its negative feedback on the anterior pituitary with slows follicle- stimulating hormone (FSH) secretion. However, it is not as prominent as progesterone’s effect.

Hormonal contraceptives can also aaddress other health conditions,in particular menstrual related disorders such as menstrual pain, irregular menstruation, fibroids, endometriosis-related pain and menstrual-related migraines. Use of combined pills for acne has been formally approved by the FDA for specific brands.

Contraceptives Types

Certain types of contraceptives may contain different combinations of hormones and include a variety of delivery methods.

Contraceptive Pill (either progesterone only, or a progesterone-estrogen combination)

By far the most common of these are the birth control pill (sometimes simply called “the pill”) of which there are currently three types: combined estrogen-progesterone, progesterone only and the continuous or extended use pill. The most commonly prescribed of these is the combined hormonal pill with estrogen and progesterone.

The contraceptive skin patch (either progesterone only, or a progesterone-estrogen combination)

A skin patch is about 5 cm by 5 cm in size, that can be placed on the woman’s behind, belly, the outside of her upper arm or anywhere on her upper body – except for breasts. Like most birth control pills, the patch contains a combination of the hormones estrogen and progestin. Whereas the hormones in the pill enter the bloodstream through the digestive system, the skin absorbs the hormones in the skin patch and enter the bloodstream in that way.

Hormone-releasing coils (Progesterone only)

A T-shaped plastic device and a string that is used to pull them out. They contain and continuously release the hormone levonorgestrel, which is absorbed by the lining of the womb. Levonorgestrel stops the lining of the womb from building up, so any fertilized eggs aren’t able to become embedded in the womb's lining. It also makes the mucus in the cervix (opening of the womb) thicker and stickier, preventing sperm from getting into the womb.

The vaginal ring (either progesterone only, or a progesterone-estrogen combination)

A ring that is approximately 5 cm in diameter and is made of a flexible synthetic material. Like the combined pill and skin patch, it also contains a combination of estrogen and progestin. These hormones are absorbed into the bloodstream through the wall of the vagina. The ring is inserted deep into the vagina and is taken out again after exactly three weeks, using a finger. The woman then has a period during the “ring-free” days that follow, and a new ring is inserted after exactly seven days.

Other hormonal contraceptives (either progesterone only, or a progesterone-estrogen combination)

Less common hormonal contraceptives include the three-month injection and the hormonal birth control implant. Contraceptive injections can be progesterone only, or a progesterone-estrogen combination, while implants are usually progesterone only.

CBD and Contraceptives - Can CBD affect birth control?

Whether CBD may influence the efficacy of hormonal contraceptives, very much depends on the type and combination of hormones it contains. Contraception methods that contain the hormone estrogen may be at a higher risk of being ineffective because of the interaction of CBD on estrogen receptors, sex hormones, and the CYP enzyme system.

CBD Competes with Estradiol

Estrogen is actually a group of hormones responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens: estrone, estradiol, and estriol.

Estradiol in particular is intimately involved with fertility with increased estradiol levels preceding the maturation and release of the egg from the ovary, as well as the thickening of the uterus lining to implant a fertilized egg.

Marijuana: interaction with the estrogen receptor.
In a 1983 study published in The Journal of Pharmacology and Experimental Therapeutics examined if crude cannabis extract competed with estradiol for binding to the estrogen receptor of rat uterine cytosol.

At large doses, they found that of the cannabinoids or their metabolites, the only one that exhibited estrogenic or non-estrogenic effects was CBD, which found to compete with estradiol for estrogen receptor binding.

The researchers concluded CBD may compete with estradiol for estrogen receptors and may prevent estrogen-based contraceptives from working properly, possibly leading to an increased risk of unwanted pregnancy. However, this binding action was clear only at very high concentrations of cannabidiol.

CBD Influences Sex Hormones

Hormonal contraceptives work because of how they influence hormone behavior, with the essential component for any hormonal contraceptive method being the action of progestogen a synthetic form of progesterone.

Progesterone is a naturally occurring sex hormone. Its primary role is the prevention of ovulation through a negative feedback mechanisms that results in a decrease in luteinizing hormone. Luteinizing hormone is associated with reproduction and ovulation, that stimulates the ovary in the release of an egg from the ovary (ovulation) in women.

Marijuana, the Endocannabinoid System and the Female Reproductive System
Although not investigating CBD on its own, a 2016 study published in the Yale Journal of Biology and Medicine reviewed the available scientific literature on cannabis use and hypothalamic-pituitary-ovarian (HPO) axis regulation, ovarian hormone production, the menstrual cycle, and fertility.

The evidence suggests that the cannabinoids found in cannabis can influence and reduce estrogen and progesterone production and anovulatory menstrual cycles. They also found that the carefully controlled regulation of the endocannabinoid system (ECS) is required for successful reproduction, and the exogenous cannabinoids in cannabis may disrupt the delicate balance of the ECS in the female reproductive system.

The role of the endocannabinoid system in female reproductive tissues
In another, more recent 2019 review study published Journal of Ovarian Research examined the data from human, animal, and in vitro studies that investigated the role of the ECS in female reproductive tissues and processes.

The reviewers found that the chronic exposure to cannabinoids such as CBD resulted in reduced ovulation in women. In addition, in females who were chronically exposed to cannabinoids, it caused a delay in sexual maturation, caused menstrual cycle disruption, and reduced serum concentrations of sex hormones.

CBD Interferes with Metabolism of Contraceptives

The cytochrome P450 system (CYP) is a special group of enzymes containing heme as a cofactor that converts fat-soluble compounds into water-soluble ones and aids in their absorption and use. The cytochrome P450 enzyme system is also responsible for breaking down over 60% percent of any drugs, including contraceptives that enters the body.

Preclinical research has shown that CBD CBD can interact directly with the CYP system, functioning as a competitive inhibitor of cytochrome P450 enzymes in the liver. It does this by binding to the site where the enzyme activity occurs, acting as a “competitive inhibitor” that displaces its chemical competitors, and thus preventing the CYP system from metabolizing other compounds.

When hormone-based contraceptives are taken with CBD, CBD can decrease the speed with which the liver breaks down these oral contraceptives. Theoretically, this could lead to an increase in levels of the contraceptive hormone and increase the contraceptive’s effectiveness. However, CBD’s enzyme inviting action may also lead to unwanted side effects, and is suspected to increase breakthrough bleeding because of excess estrogen levels as a result of a slower breakdown.

Bottom Line

The role that cannabinoids such as CBD plays on the effectiveness of hormonal contraceptives is largely unknown. However, cannabis has adverse effects on fertility in both sexes, with CBD impacting estrogen production and binding to estrogen receptors that may affect the efficacy of combination hormonal contraceptives. However, further research is needed to determine the level of CBD concentrations that is required in the body for it to impact on birth control. Before deciding to use CBD in conjunction with a hormonal birth control method, consult with a doctor, preferably an obstetrician-gynecologist, who is experienced in cannabinoids and cannabis as he or she can advise you how to combine the two safely.