What’s my chance of having twins with IVF?

It’s true that the odds of having twins is higher with IVF than conceiving naturally. But for most people having treatment, the chances are still low.

Usually, multiple pregnancies (when you carry more than one baby at the same time) from IVF happen when more than one embryo is transferred into the womb. But because this comes with increased health risks, clinics in the UK normally just transfer one embryo per cycle.

So, what are your chances of having twins with IVF? Read on to find out.

Does IVF increase my chance of having twins?

Yes, it does. But how likely you are to have twins depends on the number of embryos that are transferred.

If you have a single embryo transfer, your chance of having twins sits at around 1-3%. Here, you would have identical twins: the embryo splits into two, genetically identical embryos. To put that in perspective, the odds of identical twins in a natural pregnancy are just 0.4% (1 in 250).

Transfer two embryos and the odds shift significantly. If both implant, you can have fraternal twins (two separate eggs fertilised by two different sperm). In 2019, for people aged 35 and under, the chance of a multiple birth following double embryo transfer was over 30%.

But, as we mentioned, most clinics will transfer one embryo wherever possible.

In the UK, the guidance from the regulator (HFEA) is to transfer one embryo per cycle if there’s a good chance of success. For example, if the birthing parent is aged under 37 or if the embryos are good quality.

Yet there are cases where we may recommend transferring two (more on this later).

Why is the chance of twins higher with IVF?

We still don’t know for certain. But it might be an effect of the IVF process itself.

Some research suggests that transferring embryos at a later stage may increase the odds of identical twins. One study of 28,596 pregnancies found that identical twins were more common when embryos were transferred 5-6 days after fertilisation, versus those transferred at days 2-3. Yet other studies have found that the date of transfer doesn’t make a difference.

Other research shows that the chance of identical twins is higher in fresh versus frozen cycles.

Can I increase my chance of having twins?

The main thing that would increase your chances is to transfer more than one embryo at the same time. But this isn’t something you can choose or request: we would only recommend it in specific, individual cases.

Multiple embryo transfer may be recommended for someone with a lower chance of success: they might be 38 or older or have lower quality embryos, for example. We wouldn’t transfer multiple embryos purely to give you a higher chance of having twins.

And even if transferring multiple embryos would be the best course of action, there’s no guarantee that you would become pregnant with twins.

Can you predict whether I’ll have twins?

Not definitively, no.

Our embryologists sometimes see that a blastocyst—a embryo 5-6 days after fertilisation—has two distinct inner clusters of cells. This may suggest that it will split. The key word here is “may”: lots of embryos like this develop into single pregnancies.

How many embryos will you transfer?

We’ll make this decision after we assess the quality of your embryos. Your age, previous treatment, and medical history will also factor in.

But to reiterate: wherever we can, particularly if you’re aged under 37 and this is your first cycle, we will just transfer one embryo.

Though as we mentioned just now, there are situations where we may suggest transferring two embryos. It’s something you’ll discuss with your doctor.

How do you select embryos for transfer?

We follow the data. At ARGC, we assess each embryo’s appearance and growth patterns thoroughly.

With early-stage embryos (day 2 or 3 after fertilisation), we look at appearance and whether it has the right amount of cells.

For later-stage embryos (day 5 or 6), there’s a grading system that’s used to indicate quality. It’s based on the quality of its cells and how much the embryo has grown.

Then, from all this information, we identify the best quality embryo(s) for transfer.

Are IVF twins always identical?

If you have twins from a single embryo, they will be identical.

Fraternal pregnancies have been reported in people who had a single embryo transfer, but the chances of this happening are very slim. Here, natural conception needs to happen alongside IVF.

Start your fertility journey

Everybody is different, and your IVF treatment should reflect that.

At ARGC, IVF is precisely tailored to you: we build your treatment based on your body’s rhythms and patterns, and adjust it in real-time.

It’s not the standard way to do IVF. Yet we’ve helped thousands of people become parents over the last 30 years.

And we’ll be right there with you at every step of your journey: checking in, adjusting, and guiding you daily. We are always just a phone call away.

Wondering whether ARGC is right for you? Our advisory calls are free, no-obligation, and led by someone who can answer your specific questions about treatment, costs, and what to expect. Book a call to get started.