Jump to: What is Mounjaro? | Does weight loss increase fertility | Should I take Mounjaro before IVF? | Take home message
If you’re planning IVF treatment, Mounjaro could support weight loss to qualify for the recommended BMI threshold of between 19-30.
Still, the relationship between weight and fertility is complex, and how you approach weight loss is an important consideration before attempting to lose weight.
For example, research suggests that women with a lower BMI have higher fertility rates and lower levels of sexual dysfunction.
However, weight loss doesn’t always lead to improved fertility, as being in a calorie deficit (to support weight loss) can add extra strain on the body and lower fertility.
Whereas losing weight and then maintaining weight loss by returning calorie intake to a sustainable level will likely increase fertility.
Most NHS integrated care boards (ICBs) in England require a BMI between 19 and 30 for IVF funding.
This requirement exists because research shows that both very high and very low BMIs can affect fertility outcomes and pregnancy health.
For individuals with a BMI above 30, achieving sustainable weight loss before IVF treatment could improve their chances of success.
It’s generally recommended that Mounjaro should be stopped at least two months before starting IVF or attempting conception.
This timing allows the medication to clear from your system, as its effects on pregnancy and fetal development aren’t fully understood.
Stopping Mounjaro a few months before IVF will also allow you to increase your calorie intake to a sustainable level and maintain the weight loss achieved on medication.
For individuals considering Mounjaro before IVF, healthcare providers recommend:
- Comprehensive consultation with your fertility specialist
- Detailed planning around medication timing
- Eating a diet based on whole foods
- Maintaining other healthy habits like exercise and sleep
- Regular monitoring of health markers
- If you choose to lose weight, do so slowly and enter a period of weight maintenance a month or two before trying to conceive
What is Mounjaro?
Mounjaro is a dual-action weight-loss injection. It supports weight loss by mimicking two hormones, GLP-1 and GIP, that communicate with the brain’s appetite control centre, the hypothalamus, to lower hunger and food-seeking behaviour.
The drug in Mounjaro is tirzepatide.
By lowering hunger and our desire to eat, Mounjaro helps us eat fewer calories to achieve a calorie deficit.
A calorie deficit occurs when we consume fewer calories than our body needs to fuel its essential functions, such as digestion, blood flow, and brain function.
By creating a calorie deficit, our bodies will ‘burn’ the excess fat stored for energy, and we’ll lose weight.
Mounjaro also slows down the rate at which we digest food so that our stomach and gut send signals to the brain to signal the feeling of fullness.
So, Mounjaro supports weight loss by making us feel less hungry through two mechanisms:
- Communicating with the brain’s appetite control centre
- Slowing the rate that food is digested
Randomised controlled trials have shown that Mounjaro leads to an average weight loss of around 26% after one year.
Does weight loss improve fertility?
NHS guidelines around BMI and IVF treatment are based on extensive medical research about fertility outcomes. Most NHS integrated care boards require a BMI between 19 and 30, as this range is associated with optimal fertility and pregnancy outcomes.
This requirement is based on research showing that excess body fat can impact:
- Hormone production and regulation
- Egg and embryo quality
- Implantation success rates
- Overall pregnancy health
- Birth outcomes
For individuals with a BMI above 30, achieving a healthier weight through medical support and lifestyle changes may improve their chances of IVF success.
However, the relationship between weight loss and fertility is more complex than it might appear.
Observational studies have shown an association between weight and rates of pregnancy, live birth rates, and time to pregnancy during IVF treatment.
There’s also an association between BMI and the levels of a hormone called AMH, which predicts the number of ovarian follicles – a key marker of fertility.
This might be due to the relationship between our fat cells, insulin resistance, and inflammation.
Insulin resistance can lead to excess visceral fat levels (the fat stored in and around our internal organs), which releases pro-inflammatory proteins into the bloodstream, promoting more insulin resistance and disrupting our hormonal balance.
Insulin resistance can also increase fat cell size in your subcutaneous fat (the fat stored beneath your skin).
When this happens, these fat cells become dysfunctional and release pro-inflammatory proteins into the bloodstream, worsening insulin resistance and disrupting hormone balance.
This was demonstrated in a randomised controlled trial in 49 women comparing the effect of a weight loss intervention before fertility treatment to a control group where the participants completed the fertility treatment only.
The participants in the weight loss group underwent 6 weeks of a low-calorie diet to induce weight loss, followed by 6 weeks on a weight maintenance diet.
The study showed that participants in the weight loss intervention – who achieved an average weight loss of 6.6kg compared to 1.1kg in the control group – had higher pregnancy rates (48% vs 14%), live birth rates (44% vs 14%), and fewer cycles of IVF to pregnancy (two vs four) compared to the control group.
Contrastingly, two large randomised controlled trials with over 800 women have shown very different results.
The participants in both trials underwent a lifestyle programme lasting between 12-16 weeks before undergoing fertility treatment while following a very low-calorie diet (1200/day).
Despite significant weight loss in both trials, the results showed no difference in pregnancy and live birth rates compared to the control groups who completed fertility treatment only.
This seems counterintuitive. However, it’s possible that as there was no period of weight loss maintenance in the larger trials, the participant’s bodies were under more stress due to the strict dieting regime. This may have had an impact on their ovarian function.
During severe caloric restriction, the body enters a phase known as ‘metabolic adaptation’ that lowers energy expenditure, disrupts the balance of our reproductive hormones, and can affect ovarian function.
Animal research has found that calorie restriction can reduce fertility by affecting ovarian follicle development.
However, after a period of weight maintenance, ovarian function improves compared to the baseline (before weight loss).
It’s possible that losing excess body fat and improving insulin resistance in the long term enhances fertility and your chances of conception, but trying to conceive during or immediately after a period of rapid weight loss and strict calorie restriction may harm your chances of pregnancy.
Should I take Mounjaro before IVF?
The decision to use Mounjaro before IVF requires careful consideration of several medical factors:
- Timing: Medical guidelines recommend stopping Mounjaro at least two months before beginning IVF treatment. This allows adequate time for the medication to leave your system.
- Safety: Current medical evidence doesn’t support using Mounjaro during pregnancy or fertility treatments. The medication’s effects on fetal development aren’t fully understood.
- Weight loss: While losing weight can increase fertility, as discussed above, this needs to be approached sustainably and strategically.
- Individual factors: Your medical history, fertility status, and overall health profile will influence whether Mounjaro is appropriate for your situation.
For those considering taking Mounjaro before IVF treatment, medical professionals generally recommend:
- Detailed consultation with fertility specialists
- Comprehensive health assessment
- Clear timeline planning
- Development of sustainable health habits
- Regular medical monitoring
Take home message
The relationship between weight management and fertility is complex. While Mounjaro can support significant weight loss, its use before IVF requires careful planning and consideration of multiple health factors.
Success depends on working closely with your healthcare team to create a comprehensive plan that considers your individual medical needs, fertility goals, and overall health.
Remember that weight is just one aspect of fertility health. A holistic approach, including proper medical care, nutrition, and lifestyle support, offers the best foundation for your fertility journey.
Second Nature’s medication programmes
Second Nature has two medication-supported programmes: a Wegovy weight-loss programme and a Mounjaro weight-loss programme.
For peace of mind.
Second Nature has worked with the NHS for over 6 years, providing weight-loss programmes across the UK.
While our Wegovy and Mounjaro weight-loss programmes are private and not currently used by the NHS, we’ve built the programmes focusing on scientific evidence, patient safety, and data security.
We hope that our 6+ years of working with the NHS and building a track record of effective weight-loss results will give you peace of mind to give us a try.
