Can You Take Weight Loss Injections While Pregnant?

Are weight loss injections safe to take during pregnancy?

No — and the guidance is unambiguous. Mounjaro and Wegovy are both marked as not recommended for use during pregnancy in their UK product information. This applies whether you discover a pregnancy mid-treatment or are planning ahead. The same applies to breastfeeding: neither medicine is recommended while breastfeeding, because it is not known whether they pass into breast milk or what effect that could have on an infant.

The caution stems partly from animal studies. At doses used in animal reproductive toxicology testing, tirzepatide and semaglutide were associated with adverse effects on foetal development. Those studies used doses higher than a human therapeutic dose, so they do not map directly onto clinical risk, but because robust human safety data simply does not exist yet, the regulatory position is to treat the gap as a reason for caution rather than a green light. The NHS patient information for tirzepatide and the equivalent semaglutide page both state this clearly.

If you are pregnant and have been taking a weight loss injection, do not stop abruptly without speaking to someone first, contact your GP or midwife as soon as possible so they can advise on next steps, including monitoring and any nutritional considerations during the transition. Stopping quickly is generally the right move, but your care team should know what you were taking and when.

What should you do if you become pregnant while on treatment?

This is a question our prescribers hear most weeks, and it always warrants the same first step: contact your GP or midwife promptly rather than waiting for a scheduled review. Tell them the medicine, the dose you were on, and approximately when you last took it. They can log this in your maternity record and arrange any monitoring that is appropriate for your situation.

At nume, sorry, at nume, if a patient contacts us to let us know they are pregnant, our prescribers will not continue the prescription. That is not a bureaucratic position; it reflects the clinical reality that no safe dose in pregnancy has been established. Patients who inform us can also expect a note sent to their GP in line with standard practice.

The wash-out period (the gap between stopping the medicine and trying to conceive) is something to discuss individually with a prescriber or GP rather than follow a generic figure. It depends on which medicine you were taking and your personal circumstances. NHS England's guidance on weight management injections addresses this and recommends discussing contraception and family planning proactively, before it becomes urgent.

How does this affect contraception while on weight loss injections?

This matters more than many people realise. Women using oral contraceptive pills alongside tirzepatide (Mounjaro) are advised to add a non-oral method of contraception (such as condoms) for the first four weeks of treatment and for four weeks after each dose increase. The reason is pharmacological: tirzepatide slows gastric emptying, which can reduce how reliably oral medicines are absorbed, including the contraceptive pill. The pill may still work, but the absorption question creates uncertainty that the guidance addresses by recommending a barrier method during those windows.

For semaglutide (Wegovy), current NHS guidance does not flag the same interaction with oral contraceptives, though the general advice to use effective contraception while on any GLP-1 medicine still applies. If you have questions about whether you are suitable for weight loss injections given your contraceptive choices or plans, the consultation process is the right place to raise them, it is exactly what a prescriber reviews.

For a broader picture of weight loss injections and pregnancy considerations, including pre-conception planning, that dedicated page covers the topic in more detail. And if you're past the pregnancy stage and thinking about treatment options, our page on weight loss injections after pregnancy addresses when it may be appropriate to start.

When can you start weight loss injections after pregnancy or breastfeeding?

Once breastfeeding has fully stopped and you are not planning another pregnancy in the near term, weight loss injections may become an option again, subject to a fresh clinical assessment. There is no universal waiting period set in the licences themselves, but a prescriber will want to understand your current health, any post-partum changes, and your contraception arrangements before making a recommendation.

Weight regain after pregnancy is common and understandable, and it is a legitimate reason to explore treatment. The range of licensed weight loss injections available in the UK has expanded considerably, and a consultation is a low-pressure way to understand what might be appropriate for you specifically. At nume, at nume, consultations are free, reviewed the same day by a GPhC-registered prescriber, and carry no obligation. If treatment is clinically suitable, it can be started quickly; if it is not, you will get a clear explanation of why.

It is also worth knowing that these medicines work best alongside dietary changes, and if you are wondering whether you can drink alcohol while on weight loss injections, that is another lifestyle question our dedicated page covers in detail. Our guide to eating well on weight loss injections is a practical resource for when you do reach that stage.