GLP-1s, Pregnancy And Contraception: A Comprehensive Guide - Levity

Before starting a GLP-1 medication for weight loss, it's important you're well-informed about their effects on your reproductive health. Some medicines aren’t suitable in pregnancy, or affect your method of contraception — is this the case for medications like Mounjaro and Wegovy? In this post, our experts review their safety in pregnancy, whether they increase your risk of unexpected pregnancies and what to do if you become pregnant while taking weight loss drugs. 

How do GLP-1s help you lose weight? 

GLP-1s work by mimicking glucagon-like peptide-1, a naturally occurring hormone in your gut that helps your body turn glucose into energy. Let's break down how they promote weight loss: 

  • Regulating appetite: GLP-1s target the hunger centre in your brain, reducing hunger and increasing satiety. [1] 
  • Slowing gastric emptying: GLP-1s reduce the rate at which food moves through your stomach, increasing feelings of fullness. [2]
  • Controlling blood sugar levels: By improving your insulin sensitivity, GLP-1s reduce the risk of blood sugar spikes after you eat. [3]

Are GLP-1 medications safe during pregnancy, or while trying to conceive? 

We recommend stopping GLP-1 treatment while pregnant, or before trying to conceive. There’s not enough evidence to show that GLP-1 receptor agonists are safe for use in pregnancy. [4]

No research has been carried out to review the effect of GLP-1 drugs on fertility treatment or reproductive health. However, obesity has well-recorded effects on fertility, causing irregular periods [5] and increased risk of miscarriage [6]. It can also increase your likelihood of developing diabetes in pregnancy (gestational diabetes), which carries risks for both you and your baby. [7] Many healthcare providers may recommend you lose weight before trying to conceive to help you have a healthy pregnancy, and GLP-1s could help you achieve significant results. If you're taking GLP-1 medications in preparation for trying for a baby, we advise discontinuing treatment two months before trying to conceive. This ensures that if you fall pregnant, there's no medicine potentially still in your system. 

Weight loss drugs and oral contraception

One clinical review did find that tirzepatide, the dual-action ingredient in Mounjaro, may have a greater impact on oral birth control absorption than GLP-1 medications like semaglutide. [8] For this reason, Mounjaro's patient information leaflet recommends you switch to non-oral contraceptive methods, or add a barrier method like condoms when starting treatment and increasing your dose. 

Research into semaglutide is still ongoing. While the patient information leaflet for semaglutide doesn’t contain the same warning as Mounjaro, you should bear in mind that this medication can still cause side effects — like vomiting and diarrhoea — that could impact the efficacy of your oral contraceptives. 

Our subject matter experts recommend caution when taking birth control pills alongside GLP-1s, and to use an additional contraceptive method while taking tirzepatide (Mounjaro) or semaglutide (Wegovy, Ozempic or Compounded Semaglutide). We advise you to speak to your clinical team about the best contraception for you. 

What if I get pregnant during my weight loss program? 

If you fall pregnant while taking a GLP-1 medication, you should stop treatment immediately and speak to your doctor or clinical team. There's no need to taper yourself off your treatment, it's safe to just stop taking it. 

Can you take GLP-1s while breastfeeding?

No, you shouldn’t take GLP-1s while breastfeeding. There is a lack of evidence available on whether GLP-1 drugs enter your breast milk, or their effects on breastfed infants or lactation, but the British National Formulary (BNF) advises avoiding them to be safe. [10] If you're breastfeeding, your doctor or clinical team won't prescribe a GLP-1 medication to you to minimise any potential risks. 

We're here to support you 

Your clinical team is on hand to help you through every stage of your treatment. Don't hesitate to reach out if you have any questions about weight management, pregnancy and contraception. 

Haven't started your weight loss journey yet? See if you're eligible to try medicated weight loss today. 

 References:

1. Blundell J, Finlayson G, Axelsen M, Flint A, Gibbons C, Kvist T, et al. Effects of once‐weekly semaglutide on appetite, energy intake, control of eating, food preference and body weight in subjects with obesity. Diabetes, Obesity and Metabolism [Internet]. 2017 May 5;19(9):1242–51. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5573908/

2. Silveira SQ, da Silva LM, de Campos Vieira Abib A, de Moura DTH, de Moura EGH, Santos LB, et al. Relationship between perioperative semaglutide use and residual gastric content: A retrospective analysis of patients undergoing elective upper endoscopy. Journal of Clinical Anesthesia [Internet]. 2023 Aug 1 [cited 2023 Mar 3];87:111091. Available from: https://www.sciencedirect.com/science/article/abs/pii/S0952818023000417?dgcid=coauthor

3. Garvey WT, Batterham RL, Bhatta M, Buscemi S, Christensen LN, Frias JP, et al. Two-year effects of semaglutide in adults with overweight or obesity: the STEP 5 trial. Nature Medicine [Internet]. 2022 Oct 1;28(10):2083–91. Available from: https://www.nature.com/articles/s41591-022-02026-4

4. GLP-1 receptor agonists [Internet]. Medicinesinpregnancy.org. 2024 [cited 2024 Oct 25]. Available from: https://www.medicinesinpregnancy.org/leaflets-a-z/glp-1-receptor-agonists/

5. Itriyeva K. The effects of obesity on the menstrual cycle. Current Problems in Pediatric and Adolescent Health Care [Internet]. 2022 Jul 21;52(8):101241. Available from: https://www.sciencedirect.com/science/article/abs/pii/S1538544222001109

6. Ozcan Dag Z, Dilbaz B. Impact of obesity on infertility in women. Journal of the Turkish German Gynecological Association [Internet]. 2015 Jun 4;16(2):111–7. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4456969/

7. Bashir M, Fagier Y, Ahmed B, C Konje J. An overview of diabetes mellitus in pregnant women with obesity. Best Practice & Research Clinical Obstetrics & Gynaecology [Internet]. 2024 Feb 10 [cited 2024 Feb 12];102469. Available from: https://www.sciencedirect.com/science/article/pii/S1521693424000154

8. Skelley JW, Swearengin K, York AL, Glover LH. The impact of tirzepatide and glucagon-like peptide 1 receptor agonists on oral hormonal contraception. Journal of the American Pharmacists Association. 2023 Nov 1;

9. NICE. Semaglutide [Internet]. NICE. 2023. Available from: https://bnf.nice.org.uk/drugs/semaglutide/

Continue reading