What do the labels say about pregnancy?
They say the medicines are not for use in pregnancy, and they give a stopping interval before a planned one. The US Wegovy label states: "Because of the potential for fetal harm, discontinue WEGOVY in patients at least 2 months before they plan to become pregnant to account for the long half-life of semaglutide." It adds that weight loss offers no benefit to a pregnant patient and may cause fetal harm. Semaglutide is the medicine inside Ozempic and Wegovy.
For tirzepatide (Mounjaro), the US label says available pregnancy data are insufficient to judge the risk, and that animal studies show reduced fetal growth. The Malaysian Mounjaro label, as the PCOS article and the tirzepatide article report, advises stopping at least 1 month before a planned pregnancy. Each interval is tied to the medicine, and the comparison of the GLP-1 medicines sets them side by side. The labels read here set no separate pregnancy rule for lower doses, and what a lower dose does and does not do is covered separately.
What about the contraceptive pill?
The US Mounjaro label gives the advice in one sentence: "Advise patients using oral hormonal contraceptives to switch to a non-oral contraceptive method or add a barrier method of contraception for 4 weeks after initiation and for 4 weeks after each dose escalation with MOUNJARO." The reason it gives is delayed stomach emptying, which is largest after the first dose and fades over time. Hormonal methods that are not taken by mouth should not be affected.
The Malaysian insert is worded differently. As the PCOS article reports, it found that a single 5 mg dose lowered the peak level of ethinyl estradiol by 59%, judged this not clinically relevant, and asked that women who can become pregnant use contraception. The two documents differ in emphasis, so ask the prescriber which advice applies, and settle the contraceptive plan before the first dose and before each dose increase. Other effects on the stomach are covered in the side effects article.
Why can weight loss make pregnancy more likely?
In polycystic ovary syndrome (PCOS), weight, insulin resistance and irregular ovulation are tied together, and losing weight can bring cycles back. In a 2025 open-label trial of 100 women with PCOS, 80 of whom finished, 16 weeks of semaglutide with metformin lowered weight by 6.09 kg against 2.25 kg with metformin alone, and cycles recovered more often. Between weeks 16 and 40, with every woman on metformin alone, 35% of the semaglutide group conceived naturally against 15%.
It is one small, open-label trial, and it does not make these medicines a fertility treatment. The point for anyone on one is practical: regular ovulation can return before a pregnancy is planned, which is why the contraceptive plan matters. The wider evidence is set out in the PCOS article.
What do studies of exposure in early pregnancy show?
The largest looks at women with type 2 diabetes. A 2024 study in JAMA Internal Medicine by Cesta and colleagues followed pregnancies in four Nordic countries, the United States and Israel. Major congenital malformations (standardised prevalence) were 8.3% in 938 infants exposed to a GLP-1 medicine around conception, 7.8% in 5,078 exposed to insulin, and 5.3% in all infants of women with type 2 diabetes. After adjustment the relative risk against insulin was 0.95 (95% CI 0.72 to 1.26). The authors found no large increase above the risk of the diabetes itself, called some estimates imprecise, and asked for confirmation.
A 2026 meta-analysis of seven cohort studies and over 40,000 exposed pregnancies found no significant rise in any malformation (odds ratio 1.11, 95% CI 0.82 to 1.51), in major malformations after first-trimester exposure (1.39, 0.73 to 2.65), or in miscarriage, stillbirth, small birth size or preterm birth. A signal for urinary malformations came from unadjusted data only. The authors called the result cautiously reassuring and the certainty low.
So is exposure in early pregnancy reassuring?
In part. The data are about GLP-1 medicines mostly used for diabetes, and the confidence intervals are wide enough to leave a modest rise possible. Reassuring is a different thing from recommended. The labels still advise stopping before a planned pregnancy, and animal studies on tirzepatide showed reduced fetal growth. The sensible reading is that an unplanned exposure found early is not a reason for panic and is a reason to call the doctors promptly, as set out below.
What about breastfeeding?
The labels read here do not give one answer. In a single-dose study of 11 healthy lactating women, tirzepatide was undetectable in 164 of 171 breast milk samples, and the cumulative amount in the other 7 was under 0.02% of the mother's dose, but the label says there are no data on effects on the breastfed infant or on milk production. The US Wegovy label for the injection also says there are no data on semaglutide in human milk or its effects on the infant, and asks the doctor and mother to weigh the benefits of breastfeeding against the clinical need. The Wegovy tablet is not recommended during breastfeeding.
The clinic's own articles describe semaglutide as not used while breastfeeding, so the practical step is to settle the question with the prescribing doctor before starting, and again if you start breastfeeding while on treatment.
What to do if you find you are pregnant
Contact the doctor who prescribes the medicine, and your obstetrician, promptly. The US Wegovy label says to discontinue it when a pregnancy is recognised in someone using it for weight reduction, and the Mounjaro label asks you to tell your healthcare provider if you become pregnant. Bring the date of the last dose, since semaglutide has a long half-life.
Do not stop or change any other medicine on your own. Medicines for diabetes, blood pressure, thyroid or mental health may need adjusting in pregnancy, and that is the prescriber's decision. If you are planning a pregnancy, speak to the prescriber first so the sequence is agreed: the pause, the contraception until the interval has passed, and what happens to weight and to any other treatment. What a doctor asks before prescribing is listed in what a doctor checks before prescribing GLP-1 medication.
