Mounjaro and Pregnancy: What You Need to Know

Mounjaro is recognised as one of the most effective weight loss injections available, with some impressive before-and-after success stories from users. Despite its stellar reputation, the treatment is not suitable for everyone, so care must be taken to ensure it’s right for your circumstances.

As well as those taking certain types of medication, pregnant women or those thinking about having children are among the individuals who need to take care when debating whether to start or continue Mounjaro treatment. But why exactly is this?

Join us as we discuss Mounjaro and pregnancy, delving into key information about how the treatment affects fertility and contraception, and whether you should be taking the medication while having a baby.

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Does Mounjaro Affect Pregnancy?

Mounjaro is a prescription-only injection that is approved for weight loss and type 2 diabetes. It contains the active ingredient tirzepatide, a dual receptor agonist that targets the receptors of two digestive hormones: glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP).

GLP-1 is released into the digestive tract when you eat a meal, signalling to your brain that you're full and helping prevent overeating. GIP regulates blood sugar levels by stimulating insulin secretion from the pancreas. By mimicking the effects of these two hormones, Mounjaro suppresses appetite, slows digestion, and helps regulate blood glucose when used in conjunction with a calorie-controlled diet and regular exercise. The results are impressive, with the average weight loss on the highest dose after 72 weeks being 22.5%

Because Mounjaro slows down the time it takes for food to pass through your stomach (gastric emptying), it can affect the absorption of medications, including the contraceptive pill. But losing weight itself is also associated with increased fertility, with some research suggesting that obese women who participate in a weight loss programme are 47% more likely to conceive naturally.  

Further research shows that even a 5% to 10% weight reduction can regulate the menstrual cycle and lead to the recovery of menstruation in obese people with disorders affecting ovulation.

If you become pregnant while taking Mounjaro, it is important that you stop taking it, as it’s not known if Mounjaro is safe during pregnancy. Although there is not enough data in humans, animal studies have shown that Mounjaro’s active ingredient, tirzepatide, can have negative effects on the foetus.

If you decide you’d like to try for a baby, contact your clinician, as they can give advice about the safest ways to manage your weight or diabetes during pregnancy.

Can You Take Mounjaro When Pregnant?

No, Mounjaro isn’t recommended if you’re pregnant, trying to conceive, or not using contraception. Animal studies show a slightly higher risk of birth defects and low birth weights. While it’s unclear if this applies to humans, there’s limited evidence confirming Mounjaro’s safety during pregnancy.

For this reason, you should stop taking Mounjaro as soon as you discover you are pregnant, or if you are planning to conceive, you’ll need to stop your weight loss medication before you start trying. From a wider perspective, weight loss during pregnancy isn’t recommended, so if you are taking Mounjaro to lose weight, there is little use for it during this time, even if it were found to be completely safe. 

Is There Clinical Research Regarding Pregnancy and Mounjaro?

The research into using Mounjaro during pregnancy in humans is very limited because of ethical concerns and the potentially harmful results found in animal studies. Many medications are not recommended during pregnancy because of the potential risks to the baby, but it’s usually because the safety data in this population is limited.

Research involving animals has found that there is an increased chance of birth defects and reduced growth during pregnancy. However, this is unknown in humans because there are no studies that have investigated whether this will happen, for obvious reasons. However, due to the results of animal studies, Mounjaro should be avoided during pregnancy.

The only data available about pregnant women who have taken Mounjaro has come from women who accidentally fell pregnant during treatment. Data from women who used Mounjaro in pregnancy found:

• 6 pregnancies
• 1 healthy child
• 1 spontaneous abortion
• 1 ectopic pregnancy
• 1 elected termination
• 2 pregnancies with no reported outcomes

How Long to Stop Mounjaro Before Pregnancy

The half-life of tirzepatide, Mounjaro’s active ingredient, is approximately 5 days, meaning it takes around 25 days, or nearly 4 weeks, for it to be eliminated from the body. So, if you are planning to get pregnant, you should stop taking Mounjaro at least one month before you begin trying, to give your body enough time to completely eliminate tirzepatide.

Of course, if you would prefer to stop Mounjaro further in advance, this may be possible after speaking to your clinician. 

Accidentally Got Pregnant On Mounjaro? What to Do

If you find out that you are pregnant while taking Mounjaro, firstly, don’t panic. You should stop taking Mounjaro from the moment you learn that you are pregnant and contact your doctor straight away. You will be offered a standard, detailed 20-week scan to check that your baby is developing well, and there is usually no need for further monitoring.

Your doctor will also report your situation to an organisation that monitors drug toxicity. This is usually nothing to worry about and helps scientists better understand how Mounjaro affects pregnancy, if at all. 

Can You Take Mounjaro After Pregnancy?

Yes, you may be able to restart Mounjaro after pregnancy, but it's best to discuss this with your healthcare provider first. They will need to understand your current situation, such as how well your body is recovering after giving birth, whether or not you are breastfeeding, and if it is still appropriate for you to consider weight loss.

Your doctor may advise that you wait 3 to 6 months after birth before restarting Mounjaro, especially if you experience side effects while taking it. 

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Mounjaro and Breastfeeding Explained

Mounjaro’s active ingredient, tirzepatide, may pass into breastmilk in small amounts, so it is not advisable to take it if you are breastfeeding. Little is known about the potential effects of Mounjaro on your baby if the drug is passed into your breastmilk.

If you want to restart Mounjaro and you are breastfeeding, you should speak to your doctor. They may advise that you stop breastfeeding if you want to take Mounjaro again. However, it is essential to understand the benefits of breastfeeding and the potential risks associated with taking Mounjaro.

If your baby is bottle-fed and you want to start Mounjaro, you should also speak to your doctor. You may still need to wait a few months after delivery before you can take the medication to allow your body to fully recover from pregnancy and childbirth. 

Mounjaro and Contraception: How Does it Work?

Mounjaro can make oral contraceptives, such as the combined contraceptive pill or mini pill, less effective because it can reduce absorption through its ability to slow digestion. That means you are more at risk of becoming pregnant while taking Mounjaro for weight loss and should use a barrier method of contraception, like condoms, for four weeks after starting treatment and after every dosage increase.

Alternatively, you could consider changing to another type of birth control that’s not a pill, such as the vaginal ring, the copper coil, the implant, or the hormonal coil. If you are concerned, consult your clinician for further guidance.

Does Mounjaro Affect Fertility?

There is currently no evidence to suggest that Mounjaro affects fertility, but there is some evidence that losing weight can improve your chances of getting pregnant. Losing 5% to 10% of your body weight can have significant benefits for your overall health and fertility.

The impact of Mounjaro on male fertility in humans is unknown, but an animal study found no changes in male fertility with tirzepatide.

Weight loss, in general, can help fertility by:

• Restoring ovulation 
• Improving the effectiveness of fertility treatments 
• Reducing pregnancy risks

Mounjaro and Pregnancy: Frequently Asked Questions

Pregnancy is a time of mixed emotions, from elation to anxiety, and at the core of this is your desire to do what’s right for you and your baby. Taking medication during pregnancy can be complicated, so we aim to answer all your questions about Mounjaro and pregnancy here.

Can You Take Mounjaro When Trying to Get Pregnant?

No, you should not take Mounjaro while trying to get pregnant because not enough is known about its safety during pregnancy. If you are taking Mounjaro and want to get pregnant, you should talk to your clinician about stopping Mounjaro at least one month before you start trying to conceive.

If you become pregnant while taking Mounjaro, stop taking it and contact your doctor straight away.  

What are the Side Effects of Mounjaro While Pregnant?

There is limited research on the effects of Mounjaro during pregnancy, so the potential side effects are not fully understood. In non-pregnant individuals, Mounjaro side effects include feeling or being sick, constipation, bloating, diarrhoea, and stomach pain. Some of these can overlap with the early signs of pregnancy, such as nausea and vomiting.

Why Shouldn’t You Get Pregnant on Mounjaro?

You should avoid getting pregnant while taking Mounjaro because it’s not known how tirzepatide may affect your unborn baby. Animal studies have reported birth defects and reduced growth in babies whose mothers took Mounjaro. It is not known if this could happen in humans; however, for these reasons, Mounjaro is not recommended during pregnancy.

Are There Any Alternatives to Mounjaro When Pregnant?

No, weight loss is not advised during pregnancy. Instead, focus on maintaining a healthy lifestyle — eating a balanced diet, exercising, and promoting your overall well-being — while pregnant for the best outcomes for you and your baby. If appropriate, you can discuss weight loss after giving birth with your doctor or midwife.

Specialist Weight Loss Support from Prescription Doctor

Losing weight is a journey that can be full of many twists and turns, including plateaus and the occasional side effect. Achieving success requires hard work and determination, combined with guidance and support from medical professionals, such as clinicians. This is where Prescription Doctor can help.

Since 2013, we’ve helped countless individuals achieve their goals and navigate any challenges that come their way. From start to finish, our licensed clinicians will support you by ensuring that your chosen medication is suitable for your unique circumstances and addressing any questions you may have about your treatment.

In addition, our website provides a wealth of information about weight loss, including discussions on Mounjaro and pregnancy, guidance on administering Mounjaro injections, and an analysis of the best time of day to take the treatment. We even compare Mounjaro against other popular medications, such as Wegovy or Nevolat.

Ready to find out more? Request a consultation today and take the first steps of your journey.

Authored By

Leanne Edermaniger

Medical Content Writer

Leanne is a science and health content writer focusing on human health and biology while utilising her solid academic background.

Published on: 07/11/2025

Reviewed By

Mohamed Imran Lakhi

MPharm - Lead Pharmacist

Imran Lakhi is the superintendent pharmacist and founder at Prescription Doctor. He has been at the core of our team.

Reviewed on: 07/11/2025