TL;DR
Get baby and family essentials delivered free — and shop member deals
- Fast, free delivery on millions of items
- Access to Prime Big Deal Days deals on October 6–7
- Prime Video, Amazon Music and more included
UK regulators advise against using GLP-1 weight-loss medicines such as Wegovy and Mounjaro during pregnancy. Observational studies have not found a clear increase in major birth defects after exposure around conception or in early pregnancy, but the evidence is not strong enough to establish safety. People who discover they are pregnant while taking one should stop and contact their healthcare team.
UK guidance advises against taking weight-loss injections during pregnancy, although several human studies of accidental exposure around conception or in early pregnancy have found no clear increase in major birth defects. The findings are cautiously reassuring, not proof that the medicines are safe: the evidence is observational and limited, so regulators recommend stopping treatment if pregnancy is discovered and contacting a healthcare professional.
The Medicines and Healthcare products Regulatory Agency (MHRA) says GLP-1 medicines should not be used during pregnancy. This includes semaglutide, sold as Wegovy, and tirzepatide, sold as Mounjaro. These medicines affect appetite and blood-sugar-related hormones, slow digestion and can lead to weight loss. Pregnancy is not a time when intentional weight loss is generally used as a treatment goal; adequate nutrition supports pregnancy and fetal development.
Human research has so far offered some reassurance about exposure close to conception or in early pregnancy. A study published in JAMA Internal Medicine examined more than 3.5 million pregnancies across several countries and identified 938 pregnancies involving GLP-1 exposure around conception or early pregnancy among women with pre-existing type 2 diabetes. Major congenital malformations were recorded in 8.2% of those pregnancies and 7.8% of pregnancies among women treated with insulin. After adjustment for measured differences, researchers found no increased risk associated with GLP-1 exposure compared with insulin.
Those figures do not show that the medicines caused the recorded malformations: all women in that comparison had type 2 diabetes, which can itself affect pregnancy risks. A prospective study of about 168 first-trimester exposures also found no clear increase in major birth defects compared with control groups. A US analysis published in 2026, covering nearly 3,600 pregnancies, reported no substantial increases in major malformations, non-live births or abnormal fetal growth among those who continued treatment into the first trimester compared with those who stopped.
What Early Exposure Studies Can Tell Us
The research matters to people who learn they are pregnant after taking a weight-loss injection: the available human data have not identified a clear rise in major birth defects after early exposure. That is different from saying there is no risk. Observational studies can identify patterns, but they cannot establish that a medicine is safe or fully separate its effects from underlying health conditions and other factors.
The distinction is practical as well as scientific. Advice against planned use in pregnancy remains in place, while accidental exposure is not, on the evidence described, proof that a fetus has been harmed. Individual circumstances—including why the medicine was prescribed, how long it was taken and any other conditions—need discussion with a clinician rather than a conclusion drawn from headline study percentages.
Nutrition is another reason clinicians take a precautionary approach. These medicines can reduce appetite and food intake, and pregnancy requires appropriate nutritional support. Animal studies of semaglutide and tirzepatide have reported pregnancy loss, developmental abnormalities and reduced fetal growth in some experimental settings. In some studies, those effects occurred alongside substantial reductions in the mother’s food intake and weight, so the findings do not by themselves establish how the medicines affect human pregnancies.
GLP-1 weight loss injections pregnancy
As an affiliate, we earn on qualifying purchases.
As an affiliate, we earn on qualifying purchases.
Why Regulators Advise Against Use
There are no adequate randomised trials of these medicines in pregnancy, and animal findings raise questions that human studies have not yet resolved. Randomised trials intentionally assigning pregnant people to a medicine would present ethical and practical challenges. For now, regulators and health professionals must weigh limited human evidence against uncertainty about fetal development and maternal nutrition.
The UK Teratology Information Service (UKTIS) describes the available human evidence as reassuring but limited. It says current data do not indicate increased risks of miscarriage, malformation, intrauterine death, abnormal birth weight or premature delivery after early-to-mid-pregnancy GLP-1 exposure. That assessment does not amount to a declaration of safety, particularly for exposure later in pregnancy or for a child’s longer-term development.
The evidence base covers different medicines, exposure periods and patient groups. Much of the largest study data involves women with type 2 diabetes, while weight-loss prescriptions may be used for different reasons. Researchers also need to account for conditions such as diabetes and obesity, blood-sugar control, body weight and other medicines when interpreting outcomes.
“This is probably more common than you think”
— MadeForMums resident GP Dr Philippa Kaye
Limits of the Pregnancy Evidence
The studies cannot rule out uncommon outcomes, and observational research cannot remove all possible differences between people who used GLP-1 medicines and comparison groups. The reported results also do not establish safety throughout pregnancy: evidence is more limited for continued use later in pregnancy and for children’s long-term development.
Animal-study findings cannot be translated directly into a prediction for humans, particularly where reduced maternal food intake or weight may have contributed. At the same time, the absence of a clear risk signal in human studies does not prove that no risk exists. The size and design of the studies leave questions that further research may help answer.
Other medication-related questions remain separate from fetal-safety evidence. The report notes that Mounjaro may affect the reliability of oral hormonal contraception at certain points in treatment. It also cites emerging research detecting tiny amounts of tirzepatide in breast milk after a single dose. Those observations do not establish the effects of repeated exposure during breastfeeding; people should discuss contraception, pregnancy and feeding questions with their healthcare team.
Steps After a Positive Test
If someone discovers they are pregnant while taking Mounjaro, Wegovy or another weight-loss injection, the current advice in the report is to stop taking the medicine and contact their healthcare team. A clinician can review the medicine, timing of exposure and health history and advise on appropriate pregnancy care. The evidence does not support treating accidental early exposure as confirmation that harm has occurred.
Researchers will need larger and better-characterised pregnancy datasets to assess uncommon outcomes and exposure at different stages, as well as longer-term child development. Until that evidence is available and guidance changes, UK recommendations remain against use during pregnancy. Decisions about stopping, other treatments, contraception or breastfeeding should be discussed with a qualified healthcare professional.
Key Questions
Can you take Wegovy or Mounjaro while pregnant?
Current UK guidance says not to use GLP-1 medicines during pregnancy. The medicines covered include semaglutide (Wegovy) and tirzepatide (Mounjaro).
What if I took a weight-loss injection before I knew I was pregnant?
The report advises stopping the medicine and contacting your healthcare team. Human studies have not found a clear increase in major birth defects after early exposure, but they cannot prove the medicine is safe or determine an individual pregnancy’s outcome.
Do the studies prove these injections are safe in early pregnancy?
No. The studies are observational, and researchers cannot fully separate medicine effects from conditions such as diabetes, obesity, blood-sugar control or other medication use. Evidence is also limited for later pregnancy and long-term child development.
Why are the medicines not recommended if studies are reassuring?
There are no adequate randomised pregnancy trials, and animal studies have raised concerns. Regulators take a precautionary approach while the human evidence remains limited; reassuring findings after accidental exposure are not the same as proof of safety.
Source: rss
Halloween Picks
halloween
As an affiliate, we earn on qualifying purchases.
