This revolutionary infertility treatment is now responsible for about 2% of all births in the US annually. Plus, the live birth rate for IVF cycles has been getting steadily better over the years – roughly tripling for women under 38 since the early 1990s, according to UK data. In the US, the number of live births resulting from assisted reproductive technology – IVF accounts for 99% of such procedures – are 1.6 times higher in 2020 than they were a decade earlier.

And yet the live birth rate, per embryo transfer cycle, for women aged 35 or so is still just 30% in the UK and 39% in the US. In women of all ages, only 45% of embryo transfer cycles led to a live birth in the US, although that has grown from 36% in 2011.

It is clear that an IVF cycle is still a long, agonising roll of the dice.

Meanwhile, IVF remains gruelling for those who find themselves going through it. Multiple cycles, each one often costing thousands, can end in failure. Women inject themselves with drugs for weeks at a time, endure painful surgical procedures, while the emotional toll on couples can be severe enough to end relationships.

Scientists around the world are trying to help by working on techniques that might improve the odds of success. While there are many interwoven reasons for why IVF treatment can fail, it is possible that other interventions could make a difference. And they might transform the lives of millions.