Should I transfer one or two embryos? 5 IVF tips.
It’s a question we’re asked all the time. Should I transfer one or two embryos? Fertility patients often think transferring two embryos during IVF treatment boosts their chances. Are they right? Here’s our five-tip explainer.
1. One is best – most of the time.
Research continues to show that transferring one embryo per cycle is the safest option. Transferring two increases the chance of a multiple pregnancy and associated complications. (Not by a huge margin, but the risk is still significant.) These include pre-eclampsia, gestational diabetes and premature birth. From a purely medical angle, single embryo transfer is generally the way to go. At our clinic, the stats show that putting in two marginally boosts life birth rates. So the question boils down to this: why risk complications, particularly if you’ve got, or are likely to have, stored embryos? Back-up FET options are worth their weight in gold. Freeze and repeat is better than putting all your embryos is one basket.
2. A poor embryo can scupper your chances.
Interesting fact this, and not well-known. Transferring two embryos, when one embryo is poorer quality than the other, may lead to both embryos failing. A recent study found that, in around 25% of cases, putting in two embryos of contrasting quality led to less pregnancies than putting in one. Perhaps surprisingly, putting in two poor embryos did boost pregnancy chances. What can we take from this? The body likes consistency – and quality over quantity. Another argument for putting in one.
3. Think frozen, not fresh.
Clearly, the type of fertility treatment you have is relevant to the one-or-two debate. This is when a steer from your clinic is needed. A patient aged 40 having IVF treatment generally has a poorer prognosis than a 30-year old. Putting in two viable but medium-grade embryos during a fresh cycle may be wiser for the 40-year-old than putting in one. But consider this: FET pregnancy rates at our clinic for IVF patients are often higher than for the previous fresh transfer. Why? Because FET cycles don’t concern themselves with the heavy-duty FSH hormone medication taken in fresh cycles. So in an FET cycle after IVF, the body has a cleaner run at it. Freezing embryos after an IVF cycle may, in the end, be a better bet than transferring two in a fresh cycle – at whatever age.
4. Some bodies need single transfers.
There are other medical reasons why transferring one embryo in an IVF, donor-egg or FET cycle is sensible. A donor patient in her late 40s may well be advised to transfer one embryo to reduce strain on her uterus and placenta. Some patients who’ve had c-sections may also be better off putting one in. If a patient has a fibroid, polyp or sub-optimal endometrial lining – sometimes only spotted at the last minute – transferring one embryo and freezing the rest could be a good plan. Frozen transfers are almost as successful as fresh transfers these days. It may be inconvenient to return for an FET. But seeing your treatment as a two or three-cycle affair is better for your stress levels, not just your prospects. Repeat cycles also allow clinics to adjust and fine-tune your protocol. So an unsuccessful first cycle is simply a first step, not a disaster. Single embryo transfer is part of this new approach.
5. Don’t fall for anti-foreign-clinic clichés.
It’s a myth than non-UK clinics don’t do single embryo transfers. But read comments online and the myth persists, in the UK at least, that clinics abroad push multiple-embryo transfers on patients. Nonsense – they don’t. In the early days of IVF, clinics across the world (including the UK) more routinely transferred two or more embryos. That figure had dropped across the board. So trust in overseas clinics – particularly in the EU. The same strict European fertility regulations apply to all EU member states. And the quality and safety of treatment at EU clinics, post-Brexit, will continue.
To summarise, single embryo transfers are now routine. On balance, putting in one embryo per fertility cycle is the best option for most patients – medically, tactically and financially. The mantra really is: one at a time.