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  • Writer's pictureDr Katie Psarou

Losing weight for IVF: what you need to know

Updated: Feb 22


Need to lose 2 stone or more to qualify for IVF? (or other fertility treatments)

You are not alone!


This article explains the evidence behind weight loss and IVF success.

It helps you understand your options if you find yourself in this situation.


Let's dive in!



tape meausre for losing weight for IVF and fertilisation of egg by a sperm

What is IVF and why do you need it?

IVF stands for In Vitro Fertilisation. It’s an assisted reproductive method. It helps couples (or individuals with sperm or egg donor) to get pregnant and start a family.


Yet, it’s estimated that only 30-40% of couples that are undergoing such fertility treatments get pregnant and have a healthy baby.


Typically, couples who have been trying for a while (i.e. more than a year with regular unprotected intercourse) go through some sort of fertility treatment.


There are many reasons why you need IVF treatment or other fertility treatments:

  • Due to male factor infertility (this relates to the sperm quality and quantity)

  • Due to female factor infertility (this relates to egg quality, ovulation disorders or other hormonal issues)

  • Due to unexplained infertility (this means your doctor has run many tests and scans and found no reason why you haven’t conceived)

  • Due to an underlying physical or medical condition that makes it difficult to get pregnant

  • The only option is IVF because you are in a same-sex relationship or you want to start a family as a solo parent



Scales and tape mesaure to calculate BMI


BMI for IVF Treatment

Unfortunately, for some couples and individuals, IVF isn’t straightforward. In the UK, you’re eligible for IVF under certain criteria of which one is your BMI (Body Mass Index). This means you may have to wait a while to get on the waiting list if you have a high BMI.


What is BMI?

You can calculate your BMI by dividing your body weight in kilograms by the square of your height in metres (kg/m2).


Doctors use this measure to assess whether you’re eligible for IVF.


When you calculate your BMI you can identify which of the following general categories you fall into:

  • Underweight, BMI under 19.9

  • Healthy weight, BMI 20-24.9

  • Overweight, BMI 25-29.9

  • Obese BMI, over 30


Can you do IVF if you’re overweight?

The short answer is yes. According to the BMI classification above, if your BMI is 29 and below then you have a good chance to get pregnant with and without IVF.


What are the risks if your BMI is high?

Whether you’re a man or a woman, being overweight affects fertility and decreases the chance of falling pregnant.


Men who are overweight are more likely to:

  • have poor sperm quality

  • have less success with fertility treatments (low embryo implantation rate following IVF)

  • have a small chance of risk to miscarriage


The diet of men also influences the health of their future baby.


Excess weight in women can contribute to:

  • irregular periods

  • lower egg quality and quantity

  • taking longer to conceive


Once women get pregnant and are overweight there is a risk of pregnancy complications to both mum-to–be and baby, even after undergoing IVF. The risks include pre-eclampsia, gestational diabetes, miscarriage, preterm birth and high birth weight in babies.


So most guidelines encourage you to lose weight before any attempt at assisted reproduction methods.


Want to find out the most successful strategies my clients use to kick-start their weight loss? Download the checklist


overweight woman sitting on sofa looking sad as told to lose weigth for IVF


IVF BMI Limit

Doctors use your BMI to see if you are eligible for IVF.


You need to have a BMI of less than 30 to get NHS funding for IVF. But this changes if you are in need of other fertility treatments like intrauterine insemination (IUI) or ovulation induction. For example, if you want to start ovulation induction with letrozol or clomid then your BMI needs to be below 35.


This is a general rule of thumb. Some areas in the UK are more strict than others, so the criteria for BMI changes depending on the area that you live. It is also dependent on whether you decide to use NHS funds or go privately.


This BMI limit for IVF has been designed specifically for women rather than men. But recently, in some areas of the UK, men can be refused IVF funding if they’re classified as obese (BMI over 30).


This can be very frustrating for many couples. Particularly if the weight (and BMI) of one of you is holding you from getting the treatment you so much need. Your doctor may not even refer you unless you get to the lowest goal weight.


Unfortunately there’s limited support or guidance on how to lose weight for IVF and you deserve all the support you can get.


Many couples have been told to go and lose weight and come back in 6 months to review before they make a decision about referring them to the fertility clinic or start the process for IVF. And in that time they have gained more weight than when they first sat at the GP’s office.



scales and tape for losing weight for IVF to have a baby

Can losing weight help with IVF success?

First, you need to know what do we mean by IVF success. In this case IVF success leads to a pregnancy and a healthy baby. Although having a healthy baby is the more desirable outcome.


The more weight you lose the higher the chance of getting pregnant and having a baby through natural conception. You can significantly improve your chances of getting pregnant and having a baby by losing 5-10% of body weight.


If you've started the process of IVF (or other fertility treatment) then how to avoid weight gain during IVF might be on your mind.


How to lose weight for IVF?

There’s a lot to think about when it comes to weight loss for IVF. How fast or slow you can lose weight, what methods to use to have success and how long it would take to lose the weight.


Are you thinking of a quick weight loss before IVF?

Losing excessive weight in a very short period of time before IVF isn’t recommended. This has a negative impact on women, in particular:

  • egg quality

  • IVF success

  • increased risk of miscarriage

  • impact on the development and growth of the baby


Losing weight may be the goal. But it’s also important to be healthy and not damage or risk your health in any way just to lose it.


There are many ways to lose weight. Yet, research is lacking on how these types of weight loss methods help you get pregnant.


What methods to use to lose weight for IVF?

You can lose weight before getting pregnant by adopting a healthy fertility eating pattern and increasing your movement. If appropriate, you can follow these lifestyle changes while taking weight loss medications. Or, in certain circumstances, you can go under the knife (weight loss surgery).


But, there is a caveat. If you choose to have weight loss surgery, you are advised to postpone any plans for conception for at least 18 months after your surgery.



perosn walking up stairs and colourful fruit and vegetables

Diet and Exercise

Lifestyle strategies used in fertility research, which support weight loss, include:

  • Low calorie (from a 600Kcal deficit to at least 1200kcal per day)

  • Very low calorie diets (800Kcal per day)

  • Low fat diet where 30% of the energy intake comes from fat

  • Meal replacements (1-2 per day)

  • Diet with low glycaemic index

  • All these with or without some form of exercise (≥150 minutes/week OR ≥10000 steps daily)


You have probably heard of other methods for losing weight. The low-carb diet for fertility and intermittent fasting to get pregnant are some of the ways people seem to try, though these are yet to be scientifically investigated for their impact on fertility.


In men, losing on average 15% of body weight from a healthy diet and daily exercise can lead to improvement in:

  • hormonal profile

  • total sperm count

  • semen volume

In women, losing on average 5-10% of body weight from healthy diet and exercise can lead to improvement in:

  • hormonal profile

  • recovery of ovulation

  • menstrual cycles


Research studies show that most women who followed one of the above diet and exercise programmes achieved greater weight loss (average 3-6kg) compared to women who were given general lifestyle advice. In these studies, regardless of whether women received diet and exercise advice or not, about ⅓ of them had a successful IVF outcome. This means a pregnancy or a baby after IVF.


Unfortunately there is no clear answer on which of the above diets is best to lose weight for fertility. Many studies used different diets, time frames and groups of people, so it makes it difficult to compare.



tape mesaure for losing weight and various medications

Weight Loss Medication

While there are a couple of medication options available for weight loss, few studies used these in fertility research. In fact, to date, there is no research looking at whether weight loss medications can improve men’s fertility.


In the UK, orlistat is the only drug that’s available on prescription for anyone meeting the BMI criteria. These are a BMI over 28 with other health related conditions like diabetes, or BMI over 30. When you take Orlistat it helps you to reduce the absorption of fat from your diet by up to 30%. It is likely you can continue taking this drug if you lose 5% of your weight within 12 weeks of starting it.


Fertility research using this weight loss medication showed some good results for women before IVF with a weight loss of approximately 5% (or 2.5kg). Around 25% of the women who took orlistat or the placebo, for 4-12 weeks before a fresh embryo transfer, had a successful pregnancy. Though most women in this study had a BMI of less than 30.

Another study included women with a BMI over 33 who followed an intensive lifestyle change for 4 months (1200Kcals diet with meal replacements, orlistat and 10,000 steps per day) and women who were only advised to increase their physical activity before offering ovarian stimulation with clomid and IUI. Those following the intensive lifestyle approach lost more weight (around 6%), but only 12-15% of women from both groups had a baby after IVF.


Recent drug advancements also support the use of GLP-1 injections for weight loss[common names like semaglutide (Wegovy or Ozempic) and Liraglutide (saxenda)]. These are very powerful medications. They have an impact on your appetite by making you feel less hungry. You can lose up to 17% of your body weight with these medicines. Yet, in the UK, these drugs are only available within the NHS under a specialised multidisciplinary weight management service.


These weight loss medications are only prescribed for a short period of time (hence, not a long-term solution). You need to stop these immediately if you become pregnant because of the risk of potential toxic effects to the unborn child. So, the advice is to stop the medicines for a period of 6-7 weeks (if not more), before you start fertility treatment, to ensure that there are no traces of the drug.


A concern is that it’s very likely that you’ll gain weight after discontinuation of these medications. So, you are risking gaining weight before your appointment for IVF.



woman pre and post weight loss surgery

Bariatric surgery/ Weight loss surgery

Bariatric surgery is an option if you have a BMI over 40 or a BMI of 35 - 40 with other health related conditions. Although the waiting list for undergoing such surgery is long, unless you do it privately. For women, conception rates after weight loss surgery vary from 33% to 100%. While for men there are benefits from weight loss surgery in improving hormones, the effect on sperm is not yet clear and whether this has an impact on fertility.


How long will it take before I lose the weight for my IVF?

This depends on how much weight you have to lose to start with. Most studies on weight loss methods before IVF in men and women lasted from as little as 4 weeks and up to 48 weeks. Yet, it's unclear if a longer rather than a shorter weight loss programme has more positive outcomes.


It also depends on the BMI criteria for fertility clinics where you live and what kind of fertility treatment you are hoping to try.


If you fall in the category where your age is playing a huge factor and you have less than a year to access free IVF cycles, then you may feel under pressure as this is your last chance to lose the weight.


You might be thinking that losing weight is hard. Sometimes losing weight is not the issue but maintaining it is. This is an important factor to consider if you are time-restricted to access IVF and your biological clock is ticking.


You may already know what to do and how to do it, but actually doing it is another thing altogether. Life also happens and there are so many situations that can get you off track. Christmas, birthdays and other celebrations throughout the year are such a temptation. But sometimes just being busy at work or falling ill is all it takes.


Not everybody will lose weight at the same rate no matter what method you choose. If you have PCOS, which impacts on your fertility and weight, then you need to invest a little time figuring out the best approach to weight loss for you.


If you are trying to lose weight to optimise your health before IVF, then check out this article on how a fertility dietitian can support you on your fertility journey 



Hand holding tape measure and Mediterranean diet food

How to prepare your body for IVF

Weight loss is not the only option for improving your fertility and your chance to have a baby. You've got to be in a good physical state to undergo IVF, so starving yourself isn't sustainable or healthy at all.


If you and your partner follow a healthy fertility eating pattern and take prenatal supplements, this can have a huge impact on getting you closer to holding your baby. It's not just about what you eat, but also how you go about your day-to-day life. So making changes to your activity levels and having a good night's sleep helps.


Simple tweaks to your lifestyle can play an instrumental role in boosting your fertility and preparing you for a healthy pregnancy.



Pre IVF diet

A fertility eating pattern includes the consumption of plenty:

  • Fruits and vegetables

  • Whole grains

  • Legumes

  • Nuts

  • Fish

  • Plant-based oils like extra virgin olive oil

While limiting intakes of highly processed foods.


The healthy fertility diet is very much like the Mediterranean diet. This type of diet has shown many health benefits including:

  • better metabolic health

  • low inflammation levels and

  • healthier body weight


It supports improving fertility in those who conceive naturally or are undergoing assisted reproductive methods compared to individuals who don't follow this eating pattern.


Timing

Timing is also important. It takes at least 3 months to improve the quality of the sperm and egg. So allowing at least 3-6 months to make these improvements in your lifestyle helps you to get your body as ready as possible.



What should I do now?

Here are some final tips to reflect on and to give you direction on this journey:

  1. Find out your current BMI and the BMI criteria for your local IVF clinic

  2. Calculate how much weight you need to lose (be realistic)

  3. Find out what timeframe you have

  4. Struggling to choose where to start on your weight loss journey?

Then let me be your guide and book the Healthier Weight for Fertility Programme




photo of Dr Katie Psarou Fertility Dietitian

Dr Katie Psarou, PhD, MSc, BSc (Hons) RD MBDA

UK Registered Fertility and Maternal Health Dietitian



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