Mounjaro and Contraception: Can It Interfere With Birth Control?

In this article, we’ll look at whether Mounjaro could interfere with contraception and what this means for those using birth control. We’ll explain whether Mounjaro can make oral contraception less effective, how it might impact different types of birth control and what research suggests. We’ll also explore the role of barrier contraception methods, whether Mounjaro is safe to use during pregnancy and breastfeeding and what to consider if you're trying for a baby. If you’re taking birth control and thinking about using Mounjaro, it’s important to speak with your doctor to ensure you’re using the most effective and suitable contraception possible.

Key Takeaways

Here are the five biggest takeaways from this article about Mounjaro and contraception:

• Mounjaro slows gastric emptying, which can interfere with how well the body absorbs oral birth control pills, potentially making them less effective.

• Since Mounjaro affects oral contraceptives, using barrier methods such as condoms, diaphragms, or cervical caps can help prevent unintended pregnancy.

• Contraceptive patches, injections, intrauterine systems (IUS) and implants remain effective because they do not rely on digestion for absorption.

• Healthcare professionals advise stopping Mounjaro at least one month before trying to conceive, and it is not recommended during pregnancy or breastfeeding.

• If you are using birth control and considering Mounjaro, it’s important to speak with your doctor.

Why could Mounjaro interfere with contraception for birth control?

Mounjaro could interfere with contraception because it may affect how well oral contraceptives work, particularly in overweight or obese patients. As a result, healthcare professionals recommend using a barrier method, such as condoms or switching to a non-oral contraceptive method for at least four weeks after starting Mounjaro and after each dose increase. This advice is based on clinical trials which assessed Mounjaro’s effects on weight loss [1].

Can Mounjaro make oral contraception less effective?

Yes, Mounjaro can make oral contraception less effective. This is because it contains tirzepatide, which mimics the hormones GLP-1 and GIP. One of its effects is slowing down gastric emptying. This is the time it takes for food to leave the stomach. This delay can impact how well your body absorbs certain medications, including oral contraceptives. 

If the absorption of contraceptive pills is affected, their effectiveness may be reduced, increasing the risk of unintended pregnancy. For this reason, it is recommended to use a barrier method of contraception, such as a condom, to avoid an unwanted pregnancy.

What does the research suggest?

Research suggests that Mounjaro can reduce the effectiveness of oral contraceptive pills due to its impact on gastric emptying. The delay in stomach emptying is most significant after the first dose, which can interfere with the absorption of oral contraceptives [2].

Because of this, it’s important to be aware of the potential interactions and take extra precautions, such as using a barrier method of contraception. Further studies are needed to fully understand the extent of this interaction and how best to manage it [3].

How can Mounjaro affect birth control?

Mounjaro can affect birth control by changing the way oral contraceptives are absorbed into the body. Its active ingredient can delay and reduce the absorption of oral contraceptive pills. Studies have shown that Mounjaro can lower oral contraceptive absorption by 55–66% and delay its absorption by up to two hours, potentially making the pill less effective. However, non-oral contraceptives such as patches, injections and intrauterine systems (IUS) are not affected because they bypass the digestive system.

Can Mounjaro reduce the effectiveness of all types of contraception?

No, Mounjaro does not reduce the effectiveness of all types of contraception. It impacts oral contraceptives as it slows down stomach emptying and affects how well the body absorbs the pill. However, non-oral contraceptives such as patches, injections, intrauterine systems (IUS) and implants remain effective because they do not rely on digestion. If you are taking the pill and using Mounjaro, it’s important to consider other forms of contraception.

How can barrier methods offer a good solution?

Barrier methods offer a reliable solution for people using Mounjaro. Using a barrier method provides extra protection against unintended pregnancy. Unlike hormonal contraceptives, barrier methods do not rely on the digestive system, so their effectiveness is not affected. Condoms also offer the added benefit of protecting against sexually transmitted infections (STIs). If you are using Mounjaro and taking the pill, combining it with a barrier method can help ensure you remain protected while your body adjusts to the medication.

What barrier methods are available?

Several barrier methods are available to provide extra protection while using Mounjaro. These include:

• Male condoms – A sheath worn over the penis to prevent sperm from entering the vagina.

• Female condoms – A soft pouch inserted into the vagina to create a barrier against sperm.

• Diaphragms and cervical caps – Dome-shaped devices inserted into the vagina before sex to cover the cervix and block sperm from entering the uterus.

• Spermicides – Chemicals that kill sperm, available as gels and creams.

If you're using oral contraception while taking Mounjaro, you should use a barrier method for at least four weeks after starting treatment and after each dose increase to reduce the risk of pregnancy. 

Should I take Mounjaro if I'm trying for a baby?

If you are trying for a baby, it’s best to avoid taking Mounjaro. The effects of Mounjaro on an unborn child have not been studied, so its safety during pregnancy is not known. Because of this, healthcare professionals usually recommend postponing Mounjaro treatment until after pregnancy and breastfeeding. If you are trying to get pregnant, you should speak to your doctor or pharmacist about other methods of losing weight that are safe to do while trying for a baby.

Is Mounjaro safe to use if I'm pregnant?

Mounjaro is not safe to use during pregnancy. There is limited information known about its effects on pregnant women. Because of this, tirzepatide is not recommended for use during pregnancy or in women who could become pregnant without contraception. If you are trying to become pregnant, it is advised to stop taking Mounjaro at least one month beforehand due to its long half-life. If you become pregnant while using Mounjaro, speak to your doctor to discuss the safest options for you and your baby [4].

Is Mounjaro safe to use if I am breastfeeding?

It is unclear whether Mounjaro is safe to use while breastfeeding, as it is unknown if tirzepatide passes into breast milk. Because of this, there is a potential risk to the baby. If you are breastfeeding, you should discuss your options with your doctor and stop doing so until you have spoken to them. They will help you weigh the benefits of continuing Mounjaro treatment against the benefits of breastfeeding to determine the best approach for you and your baby [4].

Should I let my doctor know if I take birth control before starting Mounjaro?

Yes, you should let your doctor know if you take birth control before starting Mounjaro. Since Mounjaro can affect oral contraceptives, your doctor may recommend using an additional barrier method, such as condoms, or switching to a non-oral contraceptive to adequately protect against unwanted pregnancy. Talking about your contraceptive use will help your doctor provide the best advice and ensure you are using the most effective birth control while taking Mounjaro.

Final Thoughts: Does Mounjaro Affect Birth Control?

Yes. Mounjaro (tirzepatide) can affect how birth control works, particularly oral contraceptives. Because it slows down how the body processes food, it also impacts how the body absorbs medications (including forms of contraception such as birth control pills).

Mounjaro is an effective treatment for weight management. However, it’s important to consider its potential impact on oral contraceptives you may be using. Because it can reduce the absorption of birth control pills, using alternative protection, such as condoms or switching to a non-oral contraceptive, is recommended. If you’re trying for a baby, pregnant, or breastfeeding, Mounjaro may not be suitable. By understanding how Mounjaro interacts with contraception and getting medical advice, you can make informed choices to ensure your health and pregnancy plans are appropriately managed.

Medically Reviewed by:
Dr. Alexis Missick MBChB. MRCGP
GMC Reference no: 7151419
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Sources

[1] MHRA authorises diabetes drug Mounjaro (tirzepatide) for weight management and weight loss - GOV.UK

[2] THU255 Tirzepatide-induced Weight Loss In A Type 2 Diabetic Taking Oral Contraceptives - PMC

[3] The impact of tirzepatide and glucagon-like peptide 1 receptor agonists on oral hormonal contraception - PubMed

[4] Mounjaro KwikPen 2.5mg solution for injection in pre-filled pen - Summary of Product Characteristics (SmPC) - (emc)