5 Key Interactions with Hormonal Birth Control You Should Know About

Hormonal birth control, including pills, patches, injections, implants, and devices, is a widely embraced method in the United States for preventing pregnancy. Of females aged 18-64, over 90% have used contraceptives, with over 70% choosing oral birth control. 

By altering hormone levels in the body, hormonal contraceptives work to inhibit ovulation and/or thicken cervical mucus, impeding sperm from fertilizing an egg. However, while hormonal birth control is reliable when used correctly, certain interactions with other substances or health conditions can impact its safety and efficacy. 

This article provides clinical practitioners with five key insights into how hormonal birth control interacts with other factors, enabling them to offer personalized and informed care to their patients.

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Understanding Hormonal Birth Control

Before digging into these interactions, it is essential to understand the basics of hormonal birth control. Estrogen and progestin, the main hormones in these contraceptives, work together to prevent pregnancy. Estrogen inhibits the release of eggs from the ovaries, while progestin thickens cervical mucus, making it harder for sperm to reach the eggs. 

Types of Hormonal Birth Control

There are several ways to incorporate hormonal birth control into a patient’s regimen. Below is a list of some of the most popular methods:

1. Pills: Known as oral contraceptive pills (OCPs) or “the pill," they are taken by mouth every day and are one of the most commonly used forms of birth control. They come in two types: combination pills containing both estrogen and progestin and progestin-only pills.
2. Patch: A thin, beige patch is worn on the skin and changed weekly by the patient. It releases estrogen and progestin into the bloodstream through the skin.
3. Injection: This is an injection of progestin given every three months by a healthcare provider. It is a highly effective form of birth control but requires regular visits for administration.
4. Implant: A healthcare provider inserts a small, flexible rod under the skin of the upper arm. The implant releases progestin into the body and can last for up to three years.
5. Intrauterine Device (IUD): A small, T-shaped device inserted into the uterus by a healthcare provider. There are two types of IUDs: copper IUDs, which release copper to prevent fertilization, and hormonal IUDs, which release progestin to prevent ovulation.

Importance of Consistent Use and Adherence

Taking prescribed medications at the same time each day (known as adherence) is required for the effectiveness of hormonal birth control; missing doses or incorrect use can significantly decrease its ability to prevent pregnancy. 

Additionally, it's important to remember that hormonal birth control does not offer protection against sexually transmitted infections (STIs), so using condoms is recommended to safeguard against these potentially serious conditions.

The 5 Key Interactions with Hormonal Birth Control You Should Know About

More interactions could be possible, so please check with your provider if you are on hormonal birth control. However, here are the top 5 interactions:

1. Antibiotics and Hormonal Birth Control

Research suggests that only a specific group of antibiotics, known as rifamycins, can negatively affect hormonal birth control. Rifamycins, such as rifampin, rifabutin, and rifapentine, are used to treat tuberculosis and other bacterial infections. These antibiotics induce certain liver enzymes to metabolize estrogen more rapidly, potentially lowering its blood levels and reducing contraceptive efficacy.

Beyond rifamycins, most other antibiotics have not been shown to have a significant impact on hormonal birth control. Penicillins and tetracyclines have been associated with an increased risk of pregnancy when taken with birth control in a few case studies. While the evidence for this is limited, healthcare providers should consider the potential interaction and advise patients to use a secondary form of birth control during and one week after the use of one of these antibiotic classes. 

2. Anticonvulsants and Hormonal Birth Control

Certain anticonvulsant medications used to treat epilepsy or psychiatric conditions can interfere with the metabolism of hormonal contraceptives, potentially reducing their effectiveness. The interaction between anticonvulsants and hormonal birth control varies depending on the specific medication. 

Anticonvulsants, such as carbamazepine, phenytoin, and phenobarbital, are considered strongly-interacting anti-seizure medications, known to have a significant impact on the metabolism of hormonal contraceptives, potentially reducing their ability to prevent pregnancy. Studies have demonstrated that other anticonvulsants, such as lamotrigine, show lowered concentrations when taken in combination with hormonal birth control, revealing that this drug-drug interaction can be a two-way street. 

For patients who are taking anticonvulsants and hormonal birth control, healthcare providers should consider the following approaches:

• Alternative Contraceptive Methods: For patients taking anticonvulsants that are known to interact with hormonal birth control, it may be advisable to consider alternative contraceptive methods that are not affected by enzyme-inducing medications. Non-hormonal methods, such as barrier methods like condoms or copper intrauterine devices (IUDs), can be effective options.
• Adjustments in Therapy: In some cases, it may be possible to adjust the dosage or timing of hormonal contraceptives to mitigate the interaction with anticonvulsants. This should be done under the guidance of a healthcare team to ensure that contraceptive effectiveness is not compromised.
• Regular Monitoring: Patients who are taking anticonvulsants and using hormonal birth control should be monitored regularly to assess the effectiveness of the drug. This may involve checking hormone levels or using additional contraceptive methods to ensure adequate protection against pregnancy.
• Root Cause Approach: Each woman's situation is unique, and the decision regarding contraceptive options should be made on an individual basis. When advising on the most appropriate method, functional medicine practitioners should consider the patient's medical history, current medications, and contraceptive preferences.

3. St. John’s wort and Hormonal Birth Control

As of 2023, nearly three-quarters of Americans take dietary supplements. Herbal supplements, like St. John's wort (Hypericum perforatum), are notorious for drug-herb interactions. As a Traditional Chinese Medicine herb used for its benefits in mild-to-moderate depression, it can induce the same enzymes that metabolize estrogen and progestin, potentially leading to reduced hormone levels and decreased effectiveness of hormonal contraceptives. 

For this reason, patients taking birth control should disclose their use of all herbal supplements, vitamins, minerals, and nutraceuticals to their healthcare providers so that they can provide accurate and personalized guidance. The most dangerous supplement a patient is taking is the one their healthcare professional does not know about. Disclosing this pertinent information allows healthcare providers to assess the potential interactions and make appropriate recommendations to ensure the effectiveness of hormonal contraceptives.

4. Alcohol Consumption and Hormonal Birth Control

Alcohol is a part of many people's social lives, but its effects on hormonal birth control are often misunderstood. Some studies have shown a decreased rate of ethanol metabolism in women taking hormonal birth control, while others do not.

That being said, excessive alcohol consumption can lead to missed doses or inconsistent use of contraceptives, which can decrease their effectiveness in preventing pregnancy. It is imperative for patients using hormonal birth control to drink alcohol responsibly and adhere to their prescribed regimen to maintain optimal contraceptive effectiveness. 

For patients using hormonal birth control, it is advisable to follow safe drinking practices to minimize the risk of unintended pregnancy and adverse effects, such as consuming in moderation (up to one drink per day for women and two drinks per day for men), identifying the signs of alcohol intoxication, drinking water while imbibing, and using an additional contraceptive method as a backup.

5. Food and Hormonal Birth Control

While food is not typically considered a significant factor with regard to disrupting hormonal birth control, certain foods can interact with contraceptives and impact hormone levels. It is essential for patients on or considering hormonal birth control to be aware of these interactions and to inform healthcare providers of their diet.

Grapefruit Juice 

Grapefruit juice contains compounds called furanocoumarins that can interfere with the metabolism of many medications, including hormonal contraceptives. Consuming grapefruit juice in large quantities may affect estrogen metabolism in the body, potentially affecting the effectiveness of hormonal birth control. While eating grapefruit has not been shown to cause issues, other fresh juices from similar fruits, such as pomelos and tangelos, may have a similar effect on hormonal birth control.

Soy Products

Soy contains isoflavones, a type of phytoestrogen, which are compounds that mimic estrogen in the body. While moderate consumption of soy foods is generally safe and potentially beneficial for weight loss and bone health, consuming large amounts of soy products may increase estrogen levels in the body, affecting the effectiveness of hormonal contraceptives and reproductive health. Patients using hormonal contraceptives should be mindful of their intake of soy–and other isoflavone-rich foods like flax seeds–and discuss any concerns with their healthcare provider.

Maximizing Safety and Effectiveness

To ensure the optimal effectiveness and safety of hormonal birth control, it is necessary for patients to take certain precautions and follow recommended guidelines. Clinical practitioners can offer the following recommendations to their patients using hormonal contraceptives as a part of a comprehensive treatment regimen:

1. Regular Check-ups: Patients using hormonal birth control should schedule regular visits with their gynecologist to monitor the effectiveness of the contraceptive, assess any potential side effects, and make any adjustments to the treatment plan.
2. Open Communication: Patients who work with functional medicine practitioners and communicate honestly about their contraceptive use–disclosing any changes in their health status, medications, or lifestyle factors that may affect hormonal birth control–have been shown to have improved health-related quality of life outcomes. 
3. Adherence to Prescribed Regimens: Patients should take the prescribed regimen for their hormonal birth control, including taking oral contraceptives at the same time each day, changing patches as instructed, and following the recommended schedule for injections or implants. Adherence, also referred to as compliance, is one of the most vital aspects that determines the effectiveness of hormonal birth control.
4. Backup Contraception: In certain situations, such as when taking medications that may interact with hormonal birth control, using backup contraception (such as condoms) can provide additional protection against unintended pregnancy.
5. Lifestyle Modifications: Making healthy lifestyle choices, such as maintaining a nutrient-dense diet, exercising regularly, and avoiding excessive alcohol consumption, can help support the effectiveness of hormonal birth control and overall health.
6. Emergency Methods: In the event of a missed dose or a contraceptive failure, emergency contraception can be used to reduce the risk of unintended pregnancy. Women should be aware of the options available to them and how to access emergency contraception if needed.

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Key Takeaways

Understanding the potential interactions with hormonal birth control is critical for maintaining its safety and efficacy. Functional medicine practitioners using a personalized medicine approach should emphasize the importance of regular medical check-ups, open communication with healthcare providers, and adherence to prescribed regimens. 

Patients should be made aware of interactions with antibiotics, anticonvulsants, herbal supplements, alcohol, and certain foods, and need to disclose their diet and supplement use to healthcare providers. By following these recommendations and actively engaging with their interdisciplinary care team, patients can minimize the risk of interactions and ensure the optimal effectiveness of their hormonal birth control.