Is IVF success higher if eggs are collected in summer?

Hannah Millington
·Health & Wellness Reporter
·4-min read
IVF egg collection. (Supplied)
IVF success has been linked to the time of the year you do it. (Getty Images)

Previous research has pointed to IVF being more successful if eggs are harvested in summer – but should we really be planning our fertility treatments around the seasons?

Last year, for example, a clinic in Australia found it doesn't seem to matter when the frozen embryo is transferred to someone's womb, but when it's originally collected.

Analysing more than 3,600 cycles of IVF over eight years, scientists discovered women who had their eggs collected and frozen in summer months were almost a third more likely to have a successful pregnancy and birth.

IVF treatment. Embryo culture dish used for in vitro fertilisation (IVF).
Studies have found eggs collected in summer may have the best chance. (Getty Images)

IVF success linked to seasons

The live birth rate of eggs retrieved in summer was 31%, compared to 26% in autumn. Meanwhile, eggs collected in winter and spring fell between these two success rates.

"The best conditions for live births appear to be associated with summer and increased sunshine hours on the day of egg retrieval,” Dr Sebastian Leathersich, study author from Fertility Specialists of Western Australia, told The Telegraph at the time.

While the study was designed to spot a correlation and not understand the actual mechanism behind the link, researchers speculated that melatonin may play a role in producing healthy embryos and boosting an egg's chance of successful IVF.

"It is possible that there are differences in activity, diet, and lifestyle in different seasons which could underlie the observed differences in live birth rates, though such data were not collected in this study. It is also possible that other environmental factors including pollutants may impact clinical outcomes," the authors also acknowledged.

While studies have suggested higher live birth rates of IVF cycles started in spring and summer (with the study in Perth focusing specifically on collection), others have found no association, and some have even suggested higher positive IVF outcomes for cycles started in fall and winter.

So, should we really be rushing to have our eggs collected in summer (or during a specific season)?

Portrait of a mature woman in sportswear smiling outside in a park on sunny day in summer
Experts warn there are more important things we should be considering than what season it is when it comes to fertility treatment. (Getty Images)

'It's impossible to attribute IVF success to one variable without more research'

"Until more research is done, it is impossible to say with any certainty whether seasonal changes have an impact on success rates for IVF," Sandy Christiansen, embryologist and fertility coach at Béa Fertility warns, speaking to Yahoo UK.

"Whilst some studies have suggested this could be the case, fertility is incredibly complex, with many factors and variables at play. Until we have more data and research available to us, it’s impossible to attribute IVF success rates to any single variable, especially something as difficult to control for as changes in the seasons."

Christiansen emphasises that instead of focusing on "variables that could represent marginal gains for IVF success rates" it’s instead "important to zoom out and look at the bigger picture".

"What fertility patients really need is more support understanding what options are available and how they could benefit from them. For some, less invasive and more affordable fertility treatment options could help them on their fertility journeys," Christiansen adds. "IVF is not the only solution for people who are struggling to conceive. With tailored advice and more options on the fertility pathway, people who are struggling to conceive would be far more likely to find the fertility treatment that is right for them."

Deciding when the right time to start IVF is

Other than looking to the seasons to give us the answer, it's about doing what's right for you. "If you’re under the age of 35 and you’ve been trying to conceive for at least 12 months, it’s the right time to speak to your doctor and start considering your fertility options. You may not decide to undergo any treatment right away, but it’s always useful to be armed with the information you need to understand your fertility and start planning for your next step."

If you're actively trying to conceive, professionals can advise on steps to take, tests, causes of fertility difficulties and whether IVF treatment is right for you, and if it is, how your NHS Trust may be able to support you.

"IVF offers life-changing support for many patients who are struggling to conceive, but it’s not the right option for everyone, nor is it the only option available. If you’re unsure whether it’s for you, the first thing to do is to speak to a specialist and get your fertility tested."

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