GLP-1 medicines and pregnancy: what the UK product information says

On GLP-1 and pregnancy the four weight-management medicines this site covers agree on one point: Mounjaro (tirzepatide), the Wegovy injection and Wegovy tablets (semaglutide) and Foundayo (orforglipron) should not be used while pregnant. They differ on how long to stop before trying to conceive, whether the pill still works and what is known about breast milk. Here is what each UK Summary of Product Characteristics (SmPC) and patient leaflet says.

This is information only, not medical advice. All four are prescription-only; a prescriber decides whether one suits you, and anyone pregnant, breastfeeding or planning a pregnancy should talk to their prescriber, GP or midwife.

GLP-1 and pregnancy: what every SmPC says

Section 4.6 of each SmPC follows the same reasoning: little or no data from pregnant women, reproductive toxicity in animal studies, so the medicine should not be used during pregnancy. The Wegovy SmPCs recommend contraception for women of childbearing potential, Foundayo’s says they should use effective contraception, and Mounjaro’s says it is not recommended for women who could become pregnant and are not using contraception. The MHRA’s patient page goes further: use contraception, or avoid sex where pregnancy is possible, throughout treatment and the “wash-out” period after it.

Stopping before a planned pregnancy: three wash-out periods

Each SmPC sets a minimum gap before trying to conceive, based on how long the medicine stays in the body.

The NHS adds: do not stop any prescribed medicine until you have talked to your GP or specialist, and if you take a GLP-1 medicine for type 2 diabetes, your doctor will recommend other medicines in pregnancy, so the switch needs planning. What happens when you stop a GLP-1 medicine covers the weight side.

Contraception: the pill with Mounjaro and Foundayo

The four part company in section 4.5 of each SmPC.

• Mounjaro. In a single-dose study, peak levels of a combined pill’s hormones fell by more than half. The SmPC calls that not clinically relevant at a normal BMI but, with limited information in women with obesity or overweight, cannot exclude reduced efficacy: switch to a non-oral method, or add a barrier method, for four weeks after starting and after each dose increase. The NHS names condoms, a diaphragm or a cap; the MHRA adds the coil or implant.
• Foundayo. Orforglipron may reduce the efficacy of oral hormonal contraceptives: switch to a non-oral method or add a barrier method for 30 days after starting and after each dose increase.
• Wegovy injection and tablets. Semaglutide did not change exposure to a combined pill to a clinically relevant degree, so the pill is not expected to be less effective; contraception is still recommended, and the tablet’s instructions ask for a 30-minute gap before other oral medicines.

The NHS and the MHRA both point to the College of Sexual & Reproductive Healthcare for detailed guidance; the Mounjaro and Foundayo pages list the dose steps.

Breastfeeding: what each SmPC says about breast milk

• Wegovy injection: semaglutide was excreted in the milk of lactating rats; a risk to a breastfed child cannot be excluded; not to be used while breastfeeding.
• Wegovy tablets: no measurable semaglutide was found in women’s breast milk, but the tablet’s absorption enhancer, salcaprozate sodium, and some of its breakdown products were; same conclusion.
• Foundayo: unknown whether orforglipron passes into human milk; it does in animals; not to be used while breastfeeding.
• Mounjaro: in 11 women given a single 5 mg dose, milk levels were undetectable to very low, and as a chain of amino acids it is expected to be digested rather than absorbed by the baby. The SmPC concludes it “could be considered for use during breast-feeding”, though whether a mother’s reduced food intake changes the milk is not known.

That is not a green light: the leaflet says to talk to your doctor first, and the MHRA and NHS patient pages say GLP-1 medicines are not used while breastfeeding. The prescriber judges it with you.

If you find out you are pregnant while taking one

Reassurance comes from the UK Teratology Information Service’s “bumps” leaflet on GLP-1 receptor agonists, which names semaglutide, tirzepatide and orforglipron. It cites studies of about 47,000 women who mostly used a GLP-1 medicine before realising they were pregnant and stopped soon afterwards; the reports do not raise concern that the medicines harm the baby, though more research is needed, especially on later pregnancy. No extra monitoring for major birth defects is needed beyond the routine 20-week scan; a high BMI or type 2 diabetes may mean more regular monitoring. Weight loss is not recommended in pregnancy, so the medicine stays stopped; your doctor or specialist will recommend limiting weight gain through lifestyle measures instead.

The Wegovy SmPC asks that any pregnancy on Wegovy be reported to Novo Nordisk’s UK pregnancy registry; UKTIS’s MyBump Portal serves the same purpose. Suspected side effects go to the MHRA Yellow Card scheme.

Weight, fertility and planning ahead

Every SmPC says the medicine’s effect on human fertility is unknown. The NHS says being overweight or obese (a BMI of 30 or over) reduces fertility, and in women it can affect ovulation. Contraception matters from the first dose: the product information asks for it during treatment, the MHRA until the end of the wash-out period. If you want a baby, the NHS advises keeping to a healthy weight, taking folic acid and vitamin D, and speaking to a GP before trying if you take any prescribed medicine. Each leaflet also says to talk to your doctor if you are pregnant, think you may be, or are planning a baby; a UK online consultation should cover that, and our FAQ page covers the medicines themselves.

Frequently asked questions

Related reading

• Who is eligible for GLP-1 treatment in the UK?
• What a UK online consultation for GLP-1 medicines involves
• What happens when you stop a GLP-1 medicine?