There has been a rise in the use of weight loss injections to help those who are overweight manage their weight and reduce BMI. Using these injections can be helpful on your weight loss journey, but it is important to understand the impact of this medication before starting fertility treatment. As these injections are not licensed for use during fertility treatment or during pregnancy, we cannot provide fertility treatment if a female patient has used these injections in the last 2 months or if a male patient has used them in the last 3 months. Throughout this blog, you will hear how our team can advise the safest way to start your journey to parenthood, with your best chance of success.
The importance of BMI in fertility
When trying to conceive, whether naturally or with the help of fertility treatment, BMI can significantly impact success. Studies have found that maintaining a BMI within the normal range can enhance your chances of conceiving. For most adults, a BMI of 18.5 to 24.9 is considered a healthy weight.
While BMI is not a perfect measure, as this healthy range can also be influenced by factors such as muscle mass and ethnic background, using BMI is the simplest and most accessible way to assess whether you are at a healthy weight. If you are unsure about your BMI or whether you fall within the normal range, you can use an online calculator, such as the NHS BMI calculator, which allows you to include these additional factors.
Types of weight loss injections
A BMI of 30 or more is classified as obese. If you are struggling with obesity and could benefit from losing weight, there are many different types of weight loss injections that have entered the market recently. Injections can be used to address the physiological element of obesity, and when used safely, can be beneficial for those struggling to maintain a healthy weight. These medications include;
- Liraglutide (also called Saxenda)
- Semaglutide (also called Wegovy)
- Tirzepatide (also called Mounjaro)
These medications work slightly differently but the most common are known as GLP-1 agonists which function by manipulating the GLP-1 hormone the body naturally releases when you eat food. GLP-1 agonists mimic these hormone responses, slowing down the digestion of your food which makes you feel fuller for longer.
The impact of this response not only results in appetite suppression, but can also help to improve digestion and regulate hormone levels like insulin. In real world outcomes, this means patients taking these injections may find it easier to stick to a calorie controlled diet and can improve how the body processes food.
The benefits of weight loss injections
If you are struggling to maintain a healthy weight, injections have shown to be effective with many patients reporting ‘substantial weight loss’ within clinical trials.
The new generation of weight loss medicines has the potential to achieve important health and well-being benefits for the people living with obesity.
- Dr Sam Roberts, NICE chief executive
While these medications have great potential, it's important to weigh up the risks to your long-term health, financial and lifestyle goals. These medications are available on prescription via the NHS, approved weight management programmes and online pharmacies. These services will often come with additional support, using the support of medical professionals will help you discover how using this medication could allow you to meet your goals of optimising your BMI safely and on a timeline that works for you.
Using weight loss injections to reduce weight prior to fertility treatment
When used in conjunction with other underlying weight management techniques, weight loss injections may be a suitable solution if a healthcare professional has advised you to optimise your BMI before fertility treatment and you have not seen any changes with a calorie-controlled diet and increased activity levels. If you decide weight loss injections might be the right fit for you, speak to your GP or online provider about your family planning options.
The risk of weight loss injections when having fertility treatment
While we have discussed the benefits weight loss injections can have for certain patients prior to fertility treatment, it is also important to understand the risks. If you have been using weight loss injections prescribed by your GP or purchased online prior to treatment a bit of extra planning is needed to make sure you do not put yourself or your future child at risk. These risks could include;
Risks in Pregnancy
There are not enough safety studies on how these medications will affect a fetus during pregnancy, although there are some studies in animals which showed a potential for harm to the fetus. For this reason, it is important to stop taking medication before starting treatment to ensure the safety of any child born as a result of assisted reproductive techniques. The medical advice is that for the safety of the child, medication should be completely removed from the system. This means that male patients should discontinue any weight management medication at least 3 months prior to treatment, and female patients should discontinue it at least 2 months before starting treatment.
The National Institute for Health and Care Excellence (NICE) sets guidelines that highlight the recommended actions for healthcare professionals in different patient cases. Currently, they recommend that all types of weight loss injections be avoided during pregnancy. Further, it is recommended that All individuals of child-bearing potential (who are able to become pregnant) using GLP-1 medications should take steps to ensure they do not become pregnant.
Risks during treatment procedures
Separately from the risk to the fetus, there is also a risk to your own safety if you are taking weight loss injections that function by keeping you fuller for longer and planning a treatment cycle that involves sedation.
If you are having treatments that involve egg collections (such as Egg Freezing, IVF and ICSI) or Embryo Transfer (such as Frozen Embryo transfer, IVF or ICSI), our expert Anaesthetists will put you under sedation during your procedure. To make this process as safe as possible, our team will ask that you fast for a few hours before your procedure. If your rate of digestion is still lower from the effects of the medication, then it is likely there will still be food in your stomach, which increases the choking risk when going under sedation. For this reason, it is essential that we know whether or not you have taken these injections in the past 2 months.
Before every cycle, our team will conduct a medical consultation so we can offer you the best chance of success in the safest way possible. The information you provide will be used to plan your entire treatment cycle, including managing your anaesthetic, so it’s important to mention if you have been taking weight loss medication recently at this point.
The importance of pre-treatment consultation
At Manchester Fertility, our expert consultants plan every treatment cycle tailored to you based on your individual circumstances. This personalised treatment plan allows us to carry out the safest treatment for you with your greatest chance of success. It’s important you talk about your medical history in detail to our doctors. If you are concerned about your weight or taking weight loss medication to manage your BMI, our team can advise the safest way for you to continue with treatment and have the best chance of success on your path to parenthood.
Please ensure that you tell our medical and nursing team if you have used weight loss injections in the past or are planning to use them, or if you start using them at anytime during your fertility journey.
Whether you are currently in treatment or thinking about starting your journey our team are here to talk. If you have a specific question about your fertility we are here to help, you can find the best way to get touch via our contact us page.
Link to further advice about weight loss injections:
Government guidance on GLP-1 medicines: what you need to know
Last updated: 9th June 2025
