Does Mounjaro affect pregnancy?
If you’re hoping to get pregnant soon, you may be wondering how Mounjaro (tirzepatide) will affect your chances of conceiving. The same applies if you’re already pregnant or breastfeeding—is the medication safe at these times? What about if you’re looking to avoid a pregnancy?
Since many of Mounjaro’s users are women of reproductive age, there are plenty of people out there with similar questions.
Can you take Mounjaro while pregnant?
The short answer is no. Mounjaro hasn’t been tested on pregnant women, so we don’t know whether there are any risks to an unborn baby. In animal studies, it has been linked to a slightly increased risk of birth defects and low birth weight. Although animal studies don't necessarily represent what would happen in people, there is not enough research on humans to suggest Mounjaro is safe to use in pregnancy.
You should stop taking Mounjaro as soon as you see that faint line on the pregnancy test—and talk to your doctor and antenatal clinic about the next steps. Better still, stop beforehand. Weight loss during pregnancy isn’t recommended anyway, so there wouldn’t be much reason to take Mounjaro pregnant even if it were 100% safe.
What if I accidentally took Mounjaro before knowing I was pregnant?
If you've discovered you're pregnant after already taking Mounjaro, don’t panic too much. Research into this area is still emerging, and effects of Mounjaro on early pregnancy are still not clear.
That said, you should still take immediate action. Here's what you should do if you accidentally took Mounjaro while pregnant:
- Stop taking Mounjaro immediately.
- Contact your healthcare provider as soon as possible.
- Schedule a prenatal appointment to confirm your pregnancy and discuss next steps, including informing them that you have taken Mounjaro.
- If you have diabetes, discuss alternative management strategies with your doctor.
- Be honest with your healthcare providers about how long you were taking Mounjaro.
How long before pregnancy should you stop Mounjaro?
The NHS recommends stopping Mounjaro at least a month before pregnancy, (and doctors in the US recommend two months).
That’s because, tirzepatide, the active ingredient in Mounjaro, takes up to 30 days to leave your system, meaning it could affect the foetus if you got pregnant in that time.
Can I get pregnant sooner if I stop Mounjaro earlier?
Mounjaro doesn't appear to reduce fertility or make it harder to conceive once it's out of your system. The one-to-two month waiting period is specifically designed to prevent any potential exposure of the embryo to the medication during early development.
There's no evidence suggesting that stopping Mounjaro earlier than planned will enhance fertility or allow you to conceive sooner than the recommended waiting period.
Does Mounjaro help with pregnancy?
You may have heard that Mounjaro could boost the chances of getting pregnant. There are lots of reports about women who struggled with fertility issues for years, only to find they got pregnant when losing weight on Mounjaro.
To begin with the bad news—we don’t yet know whether Mounjaro has any effect on fertility. But we do know that weight loss (among those who struggle with their weight) can often make it easier to get pregnant. Being a healthy weight is also associated with healthier pregnancies, lowering your risk of complications like gestational diabetes and pre-eclampsia.
What’s more, some researchers think GLP-1 drugs (the class of drugs that includes Mounjaro) might improve fertility among women with polycystic ovary syndrome (PCOS). As well as boosting insulin sensitivity, these drugs might also tackle the hormonal imbalances that interfere with ovulation.
Can you take Mounjaro while breastfeeding?
Again, this hasn’t been directly tested, so the safest answer here is no. We don’t know how this would impact the baby. We also don’t know whether it’s likely to have any effect on milk supply.
Does Mounjaro pass into breast milk?
There's limited research on whether Mounjaro (tirzepatide) passes into breast milk. Based on what we know about similar medications, it's theoretically possible that small amounts could transfer to breast milk.
However, the active molecule in Mounjaro is probably too large to enter breast milk in large quantities, and the baby is unlikely to absorb it well. But since we don’t have a full picture of the risks yet, you shouldn’t take Mounjaro if you’re breastfeeding.
When can I restart Mounjaro after breastfeeding?
You can typically restart Mounjaro once you've completely finished breastfeeding. The timing should be discussed with your healthcare provider, who can assess your individual situation.
Many women experience weight retention after pregnancy, and your doctor might recommend waiting until your postpartum body has stabilised, usually around 3 to 6 months after delivery or after weaning.
This allows your hormones to normalise and gives you time to establish healthy eating and exercise habits. Your provider may also suggest alternative weight management approaches initially, gradually transitioning to Mounjaro if appropriate for your health goals.
Does Mounjaro affect your menstrual cycle?
There are no studies that directly link the two, so we can’t say for sure. That said, some users have reported changes. If you have PCOS, you may be used to erratic menstrual cycles, or even a period that goes AWOL. Because Mounjaro can help address hormonal imbalances, it could help restore ovulation and return some regularity to your cycle.
On the other hand, extreme and sudden weight loss can be associated with changes to your menstrual cycle. If your once-regular period has become chaotic, it’s best to talk to your GP.
Does Mounjaro affect birth control?
But what if pregnancy isn’t on your to-do list for the near future? Unfortunately, Mounjaro and contraception aren’t always the best of friends. Mounjaro works in part by slowing the emptying of the stomach, which means it can affect the absorption of contraceptives. In short, your pill might not work as well as it usually does, putting you at greater risk of falling pregnant.
If that’s not something you want to worry about, it’s recommended that you use another form of contraceptive (such as condoms) for the first four weeks after starting Mounjaro. Or you could also consider switching to a non-oral contraceptive such as the coil.
Conclusion
If you’ve had a positive experience with Mounjaro so far, it can be disheartening to think about stopping if you get pregnant. Pregnancy and the postpartum period can be a tricky time from a body image perspective, and if you’ve had to pause Mounjaro, that could add another challenge into the mix.
All this said, if Mounjaro is medically recommended for you, there will be ample opportunity to re-start in future. In the meantime, the priority is to keep yourself and your baby as safe as possible.
And if you’re not pregnant yet, but would like to be, Mounjaro may well prove helpful (see if Voy’s weight loss programme might be right for you). While there are a lot of unknowns here, clearer answers are likely to emerge over the years ahead. In the meantime, it’s wise to prioritise your health—whatever that looks like for you—before embarking on your pregnancy journey.
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