It is well-known that some fertility treatments in the UK and around the world, such as in-vitro-fertilisation (IVF) and other reproductive assistance can increase the chances of conceiving twins. While this may be a worry for some parents and couples looking to conceive, others may be excited by the prospect of twins or even triplets as a result of fertility treatment. Here, we run through all you need to know about having twins with IVF.

How Often Does IVF Cause Multiple Births?

The number of embryos transferred in an IVF cycle directly affects the chance of twins or multiple births. In previous years and in the past, it was common for doctors to transfer a higher number of embryos, which would greatly increase the chances of multiple births from a single pregnancy. Nowadays, it is more common for doctors in the UK and elsewhere to transfer a single embryo, so long as its high-quality. 

Natural twins are rare in the general population, occurring in around 2% of all pregnancies. However, when using assisted reproductive technologies such as IVF, the chances become much higher. Research shows that of all babies conceived with assisted reproduction, 43% were twins, and 3% were triplets or higher-number multiple births. Up to 50% of twins born and 75% of higher-number multiple births are a result of fertility treatments.

Why Does IVF Increase The Chance Of Twins?

IVF does not guarantee that anyone will have twins or more than one baby in a pregnancy. However, IVF can increase the chance of twins, as more than one embryo may be used. After the eggs are collected and fertilised, embryos are transferred back into the mother's womb. The number of embryos to be implanted will be discussed before treatment starts but will mainly depend on the age of the woman to be pregnant.

Women Under 37 Years Old

Women under 37 should have a single embryo transfer in their first cycle of IVF. They should also have a single transfer in their second cycle so long as more high-quality embryos are available. Doctors will typically only offer to use two embryos if there are no longer high-quality embryos available. In the third IVF cycle, a maximum of two embryos will likely be transferred.

Women Aged 37 to 39 

Women aged 37 to 39 will also tend to use single embryos in their first and second complete IVF cycles. Likewise, double embryo transfer may be considered if there are no high-quality embryos available. In the third cycle, a maximum of two embryos can be transferred.

Women Aged 40 to 42 

Women aged 40 42 can have a double embryo transfer in their first cycle of IVF. It is important to remember that the chances of conception for women aged over 40 is markedly less than for women in their 20s and 30s (particularly if younger than 35 years old.)

Can I Ask For Twins When I Get IVF?

Most doctors in the UK and around the world are opposed to trying for twins through IVF because of the potential risks it poses. Likewise, UK guidelines advise that only a single embryo should be transferred wherever possible. Some patients will request more embryos be implanted because they think it improves their chances of pregnancy. However, studies have found no difference between the success rates when using a single embryo compared to using two. Other people ask for two embryos because they hope to try for twins.

Twins may seem desirable for couples and those looking to conceive and start or grow a family, but you should not lose sight of the fact that multiple births can be expensive and can for some women and couples put a strain on their relationship. For some women and couples, there may also be some associated risks with carrying twins and all and any concerns of this nature should be discussed with your doctor or fertility expert prior to undertaking any treatment.

Remember that having twins will double feeding, clothing and other costs of raising children. Another thing to take into consideration is the inherent risk of carrying IVF twins or multiples, which will put a greater physical strain on the mother than a single child pregnancy. Additionally, if you are already paying for private healthcare in the UK or elsewhere to achieve conception for example, there will already be various costs for you to consider and account for.

When looking to undertake fertility treatment on the NHS, it is highly unlikely that the patient will be able to ask for twins or any multiples. The NHS as well as private clinics across the UK and in most countries around the world will abide by very strict guidelines and criteria, governing fertility treatments, IVF and all other associated treatments.

What Complications Are Associated With Twin Pregnancies?

Multiple pregnancies can be higher-risk for both the infant and the mother. Of course, many twins are born healthy and without complications, particularly in the UK and the Western world but their odds may sometimes not be as good as those for single babies. There are a number of complications that can take place from conception up until birth with twins or multiples. These include:

A Caesarean 

There is a high chance that you will not be able to deliver twins naturally and may therefore have to have a c–section. While this surgical procedure is common practice in more complicated births, it comes with health risks and is after all, a form of major surgery. 

Hypertension

Hypertension refers to when blood pressure goes up. Hypertension is common during any pregnancy of twins or multiples. This can place extra stress on the mother's heart and kidneys. 

Haemorrhage

In multiple pregnancies, there is a higher risk of suffering from bleeding during and after birth. The mother is also at increased risk of preeclampsia and gestational diabetes.

Prematurity

Multiple births are five times more likely to be born prematurely, although this is not necessarily a 'given' and guaranteed to happen. Premature births cause difficulties such as immature lungs, brain, gut, and brain bleeds. With twins, it is also more likely that the babies to be born will have a lower birth weight.

The main objective of IVF and all assisted reproduction treatments is to help people conceive a healthy baby. Doctors want to ensure that these treatments will not pose a risk to the mother or their infant. Therefore, doctors and all health experts do not approve of specifically trying for twins through IVF because it can be a risky endeavour and undertaking.