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Can you get pregnant on weight loss injections?
Medically reviewed by
Alexandra Cristina Cowell, Writer & Clinical Content Reviewer
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Medically reviewed by
Dr Alexandra Cristina Cowell
Writer & Clinical Content Reviewer
on Dec 11, 2025.
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Last updated on Dec 31, 2025.
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- Losing weight with weight loss injections could improve the chances of conceiving for women by up to 47%.
- There’s evidence that it can improve sperm count, motility, concentration and metabolism in men, too.
- But animal studies suggest that they could pose risks to your developing baby.
- You should stop using weight loss injections at least two months before trying to become pregnant, and avoid using them for six months postpartum.
How weight loss injections affect fertility
Current scientific evidence indicates that you shouldn’t use weight loss injections within two or three months of trying to conceive. But it also shows that losing weight before trying to start a family could improve your chances of conception.
How do weight loss injections affect female fertility?
A systematic review of the current evidence by the University of Oxford found that women who engaged with a weight loss programme before starting in vitro fertilisation (IVF) were 47% more likely to conceive than those who had little to no weight loss support.
This study analysed 12 trials across the world, involving more than 1,900 women. Further, it found that following a weight loss programme could increase the odds of becoming pregnant in any way (natural or IVF) by 21%.
There was no evidence of any increase in pregnancy loss after conceiving while using weight loss treatment, either. But many of these trials didn’t follow the pregnancies through to birth. More large-scale, high-quality studies are needed to explore the effect of weight loss injections on live births.
There’s also anecdotal evidence that women who have struggled with pregnancy in the past have unexpectedly become pregnant after losing weight with weight loss injections.
So while the current evidence surrounding conceiving after losing weight with injections is really positive – there’s still more research to be done on their effects during and after birth.
Do weight loss injections interfere with contraception?
The short answer is yes, weight loss injections can interfere with oral contraceptives. How they can affect contraception depends on the type of weight loss injections you’re using.
Current medical advice states that if you’re using tirzepatide (brand name Mounjaro) you should use an additional barrier contraceptive (like a condom) for four weeks after starting treatment, and four weeks after every dose increase.
It’s because tirzepatide is a combined GLP-1 and GIP agonist, meaning it slows down the speed at which your stomach empties more than just GLP-1 agonists (like Wegovy). This can affect how well oral contraceptives are absorbed in your stomach, impacting their effectiveness.
But other weight loss injections can indirectly affect contraception, too. Common side effects of any weight loss injections are nausea, vomiting and diarrhoea – especially after moving up a dose. If you’re sick within three hours of taking your oral contraception, or if you have severe diarrhoea within 24 hours, it can reduce the effectiveness of the pill. You should follow the guidance for missing the contraceptive pill you’re using if this happens, usually found in the patient information leaflet.
Do weight loss injections affect male fertility?
Yes – it’s thought that in men with overweight or obesity, using GLP-1 receptor agonists can improve sperm quality. Studies show that it may enhance sperm count, concentration, metabolism and motility.
While current evidence indicates that GLP-1 receptor agonists show promise in improving fertility in men with obesity and overweight, how they impact male reproductive hormones still isn’t fully understood. More research is still needed to confirm whether they can be used to treat infertility in men with overweight or obesity.
How do weight loss injections affect pregnancy?
Right now, we don’t really know. There’s not enough evidence on whether weight loss injections could be harmful to a developing baby. But there is evidence from animal studies that weight loss injections could pose risks to the developing baby. To protect you and your baby, you should avoid using weight loss injections while pregnant.
If you’re already using weight loss injections and are thinking about starting a family, current medical advice from the MHRA is to wait at least two months after stopping treatment before trying to get pregnant.
What to do if you become pregnant while taking a GLP-1
Can you use weight loss injections after pregnancy?
It depends on your health after childbirth, and whether or not you’re breastfeeding. If you are breastfeeding, then no, you shouldn’t use weight loss injections after pregnancy. We don’t know enough about whether GLP-1 agonists are excreted in breast milk, or how it could affect the health of your baby. Doctor’s advice is currently to wait for at least six months before starting weight loss medication.
So while losing weight with weight loss injections could improve fertility in men and women, if you’re using them while pregnant (or in the months leading up to your pregnancy), or breastfeeding, it could pose a risk to your baby. You should use contraception for two months after coming off weight loss treatment before trying for a baby, and avoid using weight loss injections while pregnant or breastfeeding.
Reference Popover #ref1
Treated trusted source
University of Oxford. (2025).
Women with obesity seeking IVF found to be 47% more likely to conceive naturally after weight loss. 12 Aug.
Reference Popover #ref2
Treated trusted source
The Faculty of Sexual & Reproductive Healthcare. (2025).
GLP-1 Agonists and
Contraception Patient information leaflet. FSRH. February.
Reference Popover #ref3
Treated trusted source
Skelley, J.W. et al. (2024).
The impact of tirzepatide and glucagon-like peptide 1 receptor agonists on oral hormonal contraception. Journal of the American Pharmacists Association. 64(1). pp. 204-211.
Reference Popover #ref4
Treated trusted source
Varnum, A.A. Pozzi, E. Deebel, N.A. et al. (2023).
Impact of GLP-1 Agonists on Male Reproductive Health—A Narrative Review. Medicina (Kaunas). 60(1). p. 50.
Reference Popover #ref5
Treated trusted source
Kolding, L. Henriksen, J.N. Sædder. E.A. (2025).
Pregnancy Outcomes After Semaglutide Exposure. Basic Clinical Pharmacology and Toxicology. 136(4).
Reference Popover #ref6
Treated trusted source
MHRA. (2025).
Women on “skinny jabs” must use effective contraception, MHRA urges in latest guidance. 5 Jun.
Reference Popover #ref7
Treated trusted source
NHS North East and North Cumbria. (2025).
Region's NHS warns women that weight loss injections should not be taken during pregnancy, while trying to get pregnant or when breast feeding. NHS. 17 Jun.
Reference Popover #ref8
Treated trusted source
Taylor, M. Smith, S. (2025).
Is Ozempic a safe way to lose weight postpartum? Babycenter. 9 Jun.
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