Semaglutide Pregnancy Category: What the Evidence Says

What UK and international guidance says, and why there is no 'category' in the US sense

The phrase 'pregnancy category' comes from a US Food and Drug Administration classification system that was retired in 2015. The UK does not use an equivalent lettered grading. Instead, the NHS patient information on semaglutide and the medicine's Summary of Product Characteristics state plainly that semaglutide is not recommended during pregnancy. If you have encountered the old FDA Category X label applied to semaglutide on an American website, it indicates a medicine where risks to the developing foetus outweigh any benefit, and our semaglutide and pregnancy guidance explains how UK practice arrives at the same practical conclusion, even without that label.

The evidence base that underpins this is largely preclinical. Animal reproductive toxicology studies, which regulators require before a medicine is licensed, found adverse developmental outcomes at doses within the range considered clinically relevant for humans. Human pregnancy data is sparse by design: randomised controlled trials do not enrol pregnant participants, and the Wegovy trials such as STEP 1, published in the New England Journal of Medicine, excluded women who were pregnant or planning to become pregnant. Post-marketing surveillance is ongoing, but the dataset remains limited. Where data is limited, UK prescribing practice defaults to caution, and that is entirely appropriate here.

What happens to the foetus, and why the timing of exposure matters

A question our prescribers hear most weeks is whether a brief early exposure, perhaps before a woman realised she was pregnant, carries the same concern as continued use throughout pregnancy. The honest answer is: we do not have robust human data to stratify risk by trimester, and the animal findings do not map neatly onto week-by-week human exposure. What is known is that semaglutide slows gastric emptying and reduces caloric intake substantially. Adequate nutrition, particularly folate, iron and protein, is critical in early pregnancy. A treatment that suppresses appetite and causes nausea in a significant proportion of users is unlikely to support those requirements. The potential for indirect nutritional effects, alongside the direct pharmacological unknowns, is why the potential effects of semaglutide on pregnancy are treated seriously even when the mechanism of harm is not yet fully characterised.

The guidance from NHS England on weight management injections advises using effective contraception while on treatment. For more detail on what the research and clinical evidence currently show, our page covering whether and how semaglutide affects pregnancy sets out what is known and what remains uncertain. Stopping treatment and allowing a washout period before trying to conceive is strongly recommended, the prescriber who manages your treatment can give you a precise timeframe.

Breastfeeding: a separate and equally cautious picture

It is not known whether semaglutide passes into human breast milk in meaningful quantities. Animal studies suggest it may be present in milk. Given that uncertainty, and given that weight management treatment is elective, the risk-benefit calculation during breastfeeding is straightforward: the treatment is not recommended. The NHS England guidance on weight management injections is explicit that semaglutide should not be used while breastfeeding. A newborn's developing systems would potentially be exposed to a medicine whose safety in that context is simply unknown. This is not a situation where the precautionary position is an overreaction, it reflects a genuine absence of safety data.

If you are planning to restart weight management treatment after pregnancy and once breastfeeding has ended, that is a reasonable conversation to have with a prescriber. The overview of Wegovy covers eligibility and how the treatment works for those approaching it for the first time or returning to it.

What to do if your situation has changed, or may change soon

If you are currently taking semaglutide and have just found out you are pregnant, stop the medicine and contact your GP or midwife promptly. Do not wait for your next scheduled nurse or prescriber review. Our guidance on using semaglutide during pregnancy explains why early clinical oversight matters so that your pregnancy care team has the full picture.

If you are planning a pregnancy and currently on Wegovy, begin that conversation with your prescriber well in advance, and our dedicated page on Wegovy and pregnancy is a helpful starting point for understanding what to discuss. Weight management matters during pregnancy, but it is managed through dietary and lifestyle support with specialist input, not through GLP-1 medicines. Our clinical team at nume can discuss timing and alternatives during your review, and our support team is available seven days a week if something changes between scheduled reviews. For those exploring whether Wegovy is right for them in the first place, a free consultation is the appropriate starting point, eligibility, safety and timing are all assessed individually by a GPhC-registered Independent Prescriber. General weight management treatment options are also worth reviewing if you are weighing up the broader landscape before committing to a specific medicine.