Can Saxenda improve fertility?

Time and again we’re told how everything about our pregnancies is doomed with a higher BMI. We’re fed messages that we’ll struggle to conceive, struggle to stay pregnant, struggle in labour, struggle to birth, struggle to breastfeed. Since you’re advised to lose weight for practically any health complaint (Migraine? Period pain? Ingrowing toenail? Weight loss cures it all, hurrah! No need to actually attempt to fix the problem… *sarcastic face*) we’re unsurprisingly often recommended to lose weight pre-conception, particularly if we’re seeking help because that all-important second line isn’t appearing on the pregnancy test. Some GPs advise weight loss medications like Saxenda. But can Saxenda improve fertility?

Does BMI impact fertility?

Issues can arise for those looking to get pregnant at any size. Not all studies even agree that higher BMI is associated with decreased fertility.

Body mass index and delayed conception: a European Multicenter Study on Infertility and Subfecundity by Bolúmar et al (2000) found people with a high BMI “require a longer time to conceive only if they also smoke.”

When statistics show a difference, even then, an issue (as is usually the case) is only marginally more likely with a high BMI. Your odds of everything being fine are actually pretty good. I got pregnant WAY quicker than I expected, because of all the negative nonsense I’d internalised about how fat bodies struggle to conceive.

The often cited Obesity and Time to Pregnancy, Law et al (2007) looked at the data from 7,000+ women. They calculated how much longer it took bigger bodies to get pregnant. TLDR? It’s between 1-2 months longer for most people and 3-9 months longer for up to 75% of people. They found that 25% experienced more significant problems. But that study, despite a 2007 publication date, analysed data collected in the 1950’s and 60’s! A lot has changed with people’s lifestyles and bodies since then!?

We’re not a homogenous group!

The trouble is, research tends to treat everyone with a BMI within a certain range as sharing the same characteristics. But we don’t! We know that people with Polycystic Ovary Syndrome (PCOS), Diabetes, and Hypertension (among others) are more likely to have high BMIs. We also know many such conditions are associated with reduced fertility. Any research which doesn’t adjust for these confounding factors is likely to misrepresent the real picture. But not even everyone within those sub-groups has the same experience – some people with PCOS, Diabetes and/or high blood pressure, conceive easily too. The situation is way more complicated than that.

Our ‘Completely Unscientific Poll’ last year showed the majority of BigBirthas who responded, felt they got pregnant pretty quickly.

Big Birthas Group Members' experiences of fertility - after doctors' comments re Rebel Wilson's fertility and weight prompted her into drastic weight loss. 71% said they fell pregnant really quickly, 18% said it took a while, but no moreso than thinner people they know, 11% said they struggled/are struggling with fertility.
BigBirthas answered the question “What’s your experience of getting pregnant?

Correlation vs Causation

There are many theories why a higher BMI could affect fertility, but causation hasn’t been proved. Even if higher BMI is linked with decreased fertility, without evidence, it doesn’t mean that it causes the issue.

Image shows a seagull sat on a bowed fencing panel under the caption Correlation vs Causation

It’s the classic Correlation vs Causation conundrum – as perfectly illustrated by this seagull.

It looks like the gull has bent the fence. In reality, it’s more likely something else bent the fence, the gull merely found it a convenient spot to perch. But by just looking at this image, the RSPB might conclude gulls should be prescribed Saxenda to prevent them from damaging fences in future… Which wouldn’t actually help.

So, it’s far from clear whether BMI alone does really affect fertility. You may find you have no trouble conceiving, it may take a bit longer, or you may really struggle. Just like anyone else. One thing you can be almost sure, however, is that if you are struggling to conceive and you’re ‘overweight’ or ‘obese’ by current medical definitions – frustratingly, you’re unlikely to find any doctor willing to look beyond your size for the reasons why.

But, for the sake of argument, let’s suspend our scepticism that increased BMI causes reduced fertility (since most healthcare professionals accept blindly it does). The next question is clearly:

Does losing weight improve fertility?

Well, a study published this year says not. The FIT-PLESE (*eye roll* at whoever named it) study looked at 379 women with high BMIs. They offered “a preconception intensive lifestyle intervention with acute weight loss” vs “a weight neutral intervention”. Their findings?

A preconception intensive lifestyle intervention for weight loss did not improve fertility or birth outcomes compared to an exercise intervention without targeted weight loss. Improvement in metabolic health may not translate into improved female fecundity.

Effects of preconception lifestyle intervention in infertile women with obesity: The FIT-PLESE randomized controlled trial (2022) Legro et al.

This study; Weight reduction intervention for obese infertile women prior to IVF: a randomized controlled trial by Einarsson et al (2017) found no statistically significant increase in IVF treatment success after rapid weight loss either.

But again, the picture isn’t absolutely clear. An earlier study by Legro et al Randomized Controlled Trial of Preconception Interventions in Infertile Women With Polycystic Ovary Syndrome did find an improvement, specifically in people with PCOS.

So, if you’re struggling to conceive, there’s little evidence that losing weight helps for the majority of the population.

That said, some people will want to try it anyway, especially if they feel pressured by their healthcare provider. Mentally, some people find it beneficial to have something else they can focus on to ‘do’. For others, considering weight loss can be the start of a negative spiral that’s best avoided. There are many implications and considerations – too many to go into here, and they are different for each of us. There is no ‘right’ or ‘wrong’ path here, only the path that feels right for you right now.

So, can Saxenda improve fertility?

If you’ve read this far, you’re probably pretty clear that even if BMI affects fertility, there’s little evidence that weight loss is a solution. So how could a weight loss drug make a difference?

That didn’t stop the manufacturers from attempting to position it as one.

Image of Manna Mostaghim, who has her hair in a short black bob, wearing a simple black dress and looking off camera.
Manna Mostaghim

Manna Mostaghim, a PhD Candidate in the Health Policy Department at the London School of Economics and Political Science has been looking into the murky tale of NovoNordisk pushing their product into a completely unproven market.

(Her PhD thesis is on the provision of publicly subsidised IVF for women with a high BMI in the U.K.)

Saxenda: a weight loss drug, not a fertility aid

By Manna Mostaghim

Saxenda is a weight loss drug that is prescribed to patients with a high BMI seeking to lose weight before commencing any fertility treatments. In January 2020, Saxenda was promoted at the British Fertility Conference as a fertility aid – even though the claim was scientifically unsubstantiated and Saxenda is considered unsafe to take while pregnant

The Prescription Medicines Code of Practice Authority (PMCPA) deemed Saxenda’s marketing at the conference unsafe for patients and potentially misleading for healthcare practitioners. However, misinformation that convolutes healthcare with weight loss is a common feature in the provision of fertility care for patients with a high BMI. People with a high BMI in the UK, repeatedly, characterise healthcare practitioners as having a hyper-fixation on weight loss before implementing other fertility treatments. The blame for this hyper-fixation is attributed to pre-existing and specific biases against patients with a high BMI. 

But recent research based on interviews with fertility specialists across the globe, including the UK, determined that healthcare practitioners currently have a less comprehensive understanding of fertility care than ten years ago. The research specifically indicates that fertility care is in conflict between ‘what is’ and ‘what should be’ in terms of patients seeking fertility care. 

Saxenda and the 2020 British Fertility Conference

At the 2020 British Fertility Conference, two representatives of Novo Nordisk set up a stall to promote Saxenda as a fertility aid. The representatives from Novo Nordisk that manned a stall provided written materials on Saxenda and talked to conference attendees. According to the evidence submitted to the PMCPA, the materials discussed the weight loss potentials of Saxenda but it was non-specific as to its impact on fertility and pregnancy. But the complainant that submitted misgivings to the PMCPA, claimed that the personnel that manned the stall verbally asserted that Saxenda could help the fertility of patients whilst handing written materials to conference attendees. 

The recorded facts of this incident, as shared by the PMCPA, did not explain the specifics of how the representatives said Saxenda could help fertility. But the conflation of weight loss with increased fertility remains conventional wisdom within medical care. Even though this assumption is being increasingly subject to debate, the notion that a weight loss drug may be a fertility aid would fit into the more widely accepted assumption that thinness equals fertility.     

Novo Nordisk later conceded that their representatives had only been verbally instructed on how to present Saxenda at the stall. The information that they provided was therefore not officially endorsed by Novo Nordisk and the basis of presenting Saxenda as a fertility aid cannot be ascertained by any substantive body of evidence. But the PMCPA still ruled that the promotion of Saxenda at the British Fertility Conference “failed to meet high standards”. A ruling that Novo Nordisk accepted, after an appeal. 

Potential Patient Safety Issue 

A failure to meet high standards in the promotion of pharmaceutical goods has an impact on patients and healthcare practitioners. But it is relevant to understand and contextualise to who Saxenda was being promoted to as a fertility aid. 

The PMCPA characterised conference attendees as persons that would have sufficient knowledge that Saxenda would not act as a fertility aid as they were expert fertility care specialists. This is because fertility specialists know that Saxenda is a weight loss drug that could compromise healthy fertility outcomes, pregnancy, and breastfeeding. 

But the PMCPA still decided that the promotion of Saxenda at the British Fertility Conference was a “a potential patient safety issue”. This is because this form of promotion could lead to misrepresentation of the efficacy of the drug for healthcare practitioners that were less familiar with fertility treatments. And it may prey on vulnerable patients that are willing to try anything to get pregnant if this information was disseminated more widely. 

The knowledge gaps in fertility care and patients with a high BMI   

The promotion of Saxenda as a fertility aid to healthcare practitioners could also further conflate higher BMIs as an absolute impediment to fertility. This conflation could compound difficulties for patients with a high BMI from accessing holistic fertility care from healthcare services. This is because patients with a high BMI experience weight stigma in the provision of prenatal care with healthcare practitioners. In fertility care settings this has been recorded to result in HCPs providing subpar medical care because treatment plans fixate on weight loss rather than fertility treatments.

A fixation on weight, rather than health, is said to place patients with a high BMI on the constant backfoot in terms of access and care for fertility treatment. But in 2022, Péloquin et al. collected qualitative and quantitative data from fertility specialists around the world including the UK and found that:

“There is an increasing demand for evidence-based continuing medical education and continuing professional development based on rigorous assessment of learners’ educational needs”.

This could suggest that the issue with access and care for patients with a high BMI is part of wider trend of systemic failures in fertility care for everyone. 

Fertility care

Fertility care services are expensive to run and are ever advancing. This causes a significant gap in what can be achieved and what is achieved by healthcare practitioners. This is because fertility specialists, and general practitioners, may not have sufficient time or resources to keep up to date to the latest treatments or developments in assisted reproductive technology. The promotion of Saxenda as a fertility aid could therefore be more widely accepted and implemented in fertility care by healthcare practitioners that lack the time and resources to verify claims by Novo Nordisk.   Patients with a high BMI therefore may not be suffering from (or exclusively from) weight stigma but also a lack of institutional support for fertility services. 

A combination of weight stigma, the lack of resource support for fertility services and the knowledge gap for healthcare practitioners who work in fertility care ultimately impacts patients with a high BMI that seek fertility care. 

Thanks Manna! It strikes me that while the company may have supplied leaflets which made no unsubstantiated claims, by paying for a stall at a conference about fertility they knew exactly what they were trying to imply about their product.

So, where does that leave us?

Firstly, if trying to lose weight is something you want to do, go for it. Just do so knowing it’s unlikely to impact your fertility in any meaningful way. Conversely, if you decide you don’t, be assured that the evidence shows it’s unlikely to have made any difference. Either way, the right decision is the one that feels right for you.

Of course, if you get pregnant having lost weight, you’ll never know if it would have happened anyway. Or it may be that some other lifestyle change should get credit. Other subtle lifestyle changes often accompany weight loss attempts – eg increased exercise or reduced alcohol consumption. Sometimes it’s just pure chance.

If you want to try a product like Saxenda, again, that’s completely your choice. Just be conscious that it’s NOT considered safe to take while pregnant, and there’s zero evidence it improves fertility. Be very wary of anyone saying otherwise.

The only potential benefit I can see of taking any form of weight loss medication is almost as a placebo. Not for the person taking it, but for the health care professionals providing it. Because if you lose weight and still struggle to conceive, then they might actually investigate the issue. It’s sad that I’m even writing this, but I fear this is the general state of services and pervasive weight stigma in the UK at present.

Good luck, whatever you choose to do, and take care of yourself.


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