Many people taking GLP-1 receptor agonists for diabetes or weight management wonder whether these medications affect fertility. Whilst GLP-1 medications such as semaglutide (Ozempic, Wegovy) and liraglutide (Victoza, Saxenda) are not fertility treatments, emerging evidence suggests they may indirectly influence reproductive health through weight loss and metabolic improvements. This article examines the current understanding of GLP-1 medications and fertility, including their effects on menstrual regularity, contraception considerations, and guidance for those planning pregnancy. Understanding these connections is essential for informed decision-making about your reproductive health whilst using GLP-1 therapy.

What Are GLP-1 Medications and How Do They Work?

Glucagon-like peptide-1 (GLP-1) receptor agonists are a class of medications originally developed for managing type 2 diabetes, with some now also approved for weight management. In the UK, medications include semaglutide (Ozempic for diabetes; Wegovy for weight management), liraglutide (Victoza for diabetes; Saxenda for weight management), and dulaglutide (Trulicity for diabetes only).

These medications work by mimicking the action of naturally occurring GLP-1, a hormone released by the intestines after eating. GLP-1 receptor agonists enhance insulin secretion when blood glucose levels are elevated, suppress glucagon release (which normally raises blood sugar), and slow gastric emptying. This combination helps regulate blood glucose levels more effectively in people with type 2 diabetes.

Beyond glycaemic control, GLP-1 medications have a significant effect on appetite regulation. They act on receptors in the brain's hypothalamus and other areas involved in satiety signalling, leading to reduced hunger and increased feelings of fullness. This mechanism contributes to weight loss, with clinical trials of semaglutide 2.4mg (Wegovy) demonstrating average weight reductions of 10–15% of body weight over 12–18 months. Other GLP-1 medications typically produce more modest weight loss.

The medications are typically administered via subcutaneous injection, either daily or weekly depending on the specific formulation. Common side effects include nausea, vomiting, diarrhoea, and constipation, which often diminish over time as the body adjusts to treatment. More serious but rare adverse effects can include pancreatitis and gallbladder disease. If you experience side effects, report them to your healthcare professional or via the MHRA Yellow Card Scheme (yellowcard.mhra.gov.uk).

Understanding how these medications work is essential context for exploring their potential effects on reproductive health and fertility.

The Link Between GLP-1 Agonists and Fertility

The relationship between GLP-1 receptor agonists and fertility is complex and not fully established through direct clinical evidence. There is no official link confirmed by regulatory bodies such as the MHRA or NICE stating that GLP-1 medications directly enhance fertility. However, emerging clinical observations and patient reports have prompted healthcare professionals to consider potential indirect effects on reproductive function.

Regarding contraception, the effects of GLP-1 medications vary by product:

• For semaglutide (Ozempic, Wegovy), liraglutide (Victoza, Saxenda), and dulaglutide (Trulicity), no clinically relevant interactions with oral contraceptives have been established in product information. However, if you experience severe vomiting or diarrhoea whilst taking these medications, follow standard UK missed pill guidance as absorption may be affected.

• For exenatide and lixisenatide, timing matters – oral contraceptives should be taken at least 1 hour before or 11 hours after injection due to delayed gastric emptying.

Some women with polycystic ovary syndrome (PCOS) have reported improved menstrual regularity whilst taking GLP-1 medications, though this is likely related to weight loss and improved insulin sensitivity rather than a direct pharmacological effect on ovarian function. PCOS is strongly associated with insulin resistance and obesity, both of which can impair ovulation. By addressing these underlying metabolic disturbances, GLP-1 agonists may indirectly support more regular ovulatory cycles.

Current prescribing guidance advises against using GLP-1 medications during pregnancy. For pregnancy planning, discontinuation timing is product-specific:

• Semaglutide (Ozempic, Wegovy): Stop at least 2 months before attempting conception

• For other GLP-1 medications: Consult the specific product information and discuss with your healthcare provider

Healthcare professionals should counsel patients of reproductive age about these considerations and the importance of effective contraception whilst on treatment. Further research is needed to fully characterise any effects of GLP-1 agonists on fertility parameters in both women and men.

Effects of Weight Loss on Reproductive Health

Weight loss achieved through any means—including GLP-1 medications—can have profound effects on reproductive health, particularly in individuals with obesity-related fertility impairment. Excess body weight is associated with numerous reproductive disorders in both women and men, and even modest weight reduction of 5–10% can lead to significant improvements in fertility outcomes.

In women, obesity is linked to:

• Anovulation and irregular menstrual cycles: Excess adipose tissue produces oestrogen and inflammatory mediators that disrupt the hypothalamic-pituitary-ovarian axis, leading to irregular or absent ovulation.

• Polycystic ovary syndrome (PCOS): Approximately 40–80% of women with PCOS are overweight or obese. Weight loss improves insulin sensitivity, reduces androgen levels, and can restore ovulatory function.

• Reduced success with fertility treatments: Obesity is associated with lower pregnancy rates and higher miscarriage rates in women undergoing assisted reproductive technologies.

For men, obesity contributes to:

• Reduced testosterone levels: Adipose tissue converts testosterone to oestrogen through aromatase activity, leading to hypogonadism.

• Impaired sperm quality: Studies have shown associations between elevated body mass index (BMI) and reduced sperm concentration, motility, and morphology.

• Erectile dysfunction: Obesity-related vascular and hormonal changes can impair sexual function.

Weight loss through GLP-1 medications may therefore improve fertility indirectly by addressing these obesity-related mechanisms. Clinical studies have demonstrated that weight reduction improves ovulation rates, menstrual regularity, and spontaneous pregnancy rates in women with obesity. Similarly, men who lose weight often experience improvements in testosterone levels and sperm parameters. However, it is crucial to emphasise that GLP-1 medications should be discontinued before attempting conception following product-specific guidance, and any fertility benefits are likely mediated through weight loss and metabolic improvements rather than direct drug effects on reproductive organs.

Discussing Fertility Concerns with Your Healthcare Provider

If you are taking or considering GLP-1 medication and have concerns about fertility, open communication with your healthcare provider is essential. Your GP or specialist can provide personalised advice based on your individual circumstances, medical history, and reproductive goals.

Key topics to discuss include:

• Your fertility plans and timeline: If you are planning to conceive in the near future, your healthcare provider can advise on the appropriate timing for discontinuing GLP-1 medication. For semaglutide (Ozempic, Wegovy), stop at least two months before attempting pregnancy. For other GLP-1 medications, follow product-specific guidance and your clinician's advice.

• Contraception whilst on treatment: Discuss the most appropriate contraceptive method for your situation. While most GLP-1 medications don't directly reduce contraceptive efficacy, severe vomiting or diarrhoea could affect absorption of oral contraceptives. Barrier methods, intrauterine devices (IUDs), or contraceptive implants may be recommended.

• Underlying conditions affecting fertility: If you have PCOS, irregular periods, or other reproductive health concerns, your healthcare provider can assess whether weight loss through GLP-1 treatment might benefit your fertility and discuss alternative or complementary approaches.

• Monitoring and investigations: Depending on your circumstances, your GP may recommend fertility investigations or referral to a specialist. NICE guidance suggests that couples should be offered fertility assessment if they have not conceived after 12 months of regular unprotected intercourse, or after 6 months if the woman is 36 years or over, or earlier if there are known fertility concerns.

When to seek urgent advice:

Contact your GP or healthcare provider promptly if you:

• Suspect you may be pregnant whilst taking GLP-1 medication

• Experience sudden changes in menstrual patterns

• Develop severe abdominal pain (especially if radiating to the back), persistent vomiting, or signs of gallbladder problems

• Experience severe, persistent vomiting or diarrhoea leading to dehydration

Your healthcare team can coordinate care between endocrinology, gynaecology, and fertility services as needed, ensuring that your weight management and reproductive health goals are addressed safely and effectively. Remember that fertility is influenced by numerous factors, and a comprehensive assessment will consider your overall health, age, and any underlying medical conditions alongside the effects of weight and medication.

Frequently Asked Questions