For couples struggling with infertility, IVF can be used to increase the chances of getting pregnant. However, as with any medical procedure, there are potential risks and complications to consider before starting treatment. One such risk is the possibility of having twins or multiple babies at birth, which is a common occurrence during IVF.
This is often due to the number of embryos that are transferred to the uterus during the IVF process. While having a child is a beautiful experience, it can be frustrating for those who are unable to conceive naturally. Fortunately, assisted reproductive technology, such as IVF, has provided hopeful parents with an option to have children. Nonetheless, it is important to understand the potential risk of having twins or multiple births with IVF.
What are the chances of having twins in IVF?
Like any medical procedure, IVF comes with some risks. One of the most common risks associated with this treatment is the likelihood of having twins or multiple babies. The number of embryos that are transferred to the uterus during an IVF cycle directly affects the chances of having twins or multiples. In the past, when more embryos were transferred, the number of multiple births increased.
Normally, the chances of having twins naturally are around 2%, which is quite rare. However, assisted reproductive technologies have changed this. Research by the Centers for Disease Control (CDC) has shown that among infants conceived through ART:
- 43% were twins
- 3% were triplets or even more babies
In other words, while infertility treatments only account for up to 3% of all single live births, they may account for as much as 50% of twins and 75% of higher-order multiple births. (1)
Does PGT testing increase the chance of twins?
Preimplantation genetic testing (PGT) doesn’t boost the likelihood of twins, though. Before embryos are implanted in the uterus during in vitro fertilization (IVF), they are screened using the PGT method for genetic abnormalities. One or more embryonic cells are taken out during the screening process, and they are examined for chromosomal flaws or genetic diseases.
By using IVF, there is a higher probability of having twins than when using natural conception since more embryos can be placed in the uterus to boost the likelihood of pregnancy. However, the patient’s age and other criteria, not the presence or absence of PGT, typically influence the number of embryos transferred.
In fact, according to some research, PGT may somewhat reduce the likelihood of multiple births. This is so that fewer embryos need to be transferred to maximize the likelihood of a healthy pregnancy. The testing procedure can assist in identifying the most viable embryos for transfer.
Just 1% of births after a single embryo transfer results in twins, whereas 27% of births after multiple embryo transfers do. It is risky to carry and deliver several infants. With multiple gestation births, there is a significant (2x–5x) increase in complications for both the mother and the baby during delivery.
What are the risks of twins in IVF?
If you have been trying to get pregnant, you may be wondering why having twins or multiples would be problematic. However, having twins or multiples increases the risk of complications during pregnancy. Some of the most common risks associated with twins include:
- Premature birth: As mentioned earlier, more than half of twins are born prematurely, which occurs in about 60% of cases.
- Low birth weight: Because many twins are born prematurely, they typically weigh less at birth. In fact, over 50% of newborn twins weigh less than 2.5 kg.
- Twin-to-twin transfusion syndrome (TTTS): This is a serious condition where one twin receives too much blood flow through the placenta, while the other receives too little. TTTS can be fatal for both babies and affects about 10% of cases with identical twins.
- Pre-eclampsia: This is a dangerous condition characterized by high blood pressure, protein in the urine, and leg swelling, which is risky for both the mother and the baby. The risk for pre-eclampsia is twice as high for mothers carrying twins.
By carefully managing your IVF treatment, your doctor can help you conceive without the risk of having twins or multiples. As a fertility specialist, your doctor aims to help you give birth to one healthy baby. (2)
Will the cost increase if we want twins?
The transfer of multiple embryos during the embryo transfer phase of IVF became appealing due to a complicated combination of factors, including the expense of IVF in the United States and the increasing age of mothers. By transferring more embryos, parents could increase their chances of conception during the first IVF cycle instead of paying for multiple cycles.
However, the associated risks and expenses are much higher. While these couples may save money during the initial fertility treatment process, they typically end up spending much more money in the long run to support twins, triplets, quadruplets, or more.
It’s important to understand that multiples are significantly more expensive, from the cost of their births to their daily expenses such as food, clothing, and other necessary care. This is in addition to the inherent risks involved in carrying IVF twins or multiples. (3)
Should you transfer more than one embryo to increase twin chances?
Deciding whether to transfer more than one embryo in the pursuit of twins through In Vitro Fertilization (IVF) is fraught with complexity. Initially, it might appear that increasing the number of embryos transferred boosts the likelihood of twins. However, this approach is generally not recommended due to the associated higher risks. These include a greater chance of complications during pregnancy. Specifically, twin pregnancies are more prone to result in preterm birth and low birth weight. Furthermore, both the mother and babies face an elevated risk of health issues.
In light of these concerns, fertility clinics now prioritize the transfer of a single healthy embryo. This strategy is aimed at fostering a safer pregnancy, with a greater probability of delivering a single, healthy baby. Advances in embryo selection and reproductive technologies have significantly enhanced the success rates of single embryo transfers. Such improvements have made it possible to achieve high rates of success without the need to resort to multiple transfers. Therefore, while the dream of twins might be enticing, the focus remains on ensuring the health and safety of both mother and child through the transfer of a single, well-chosen embryo.
Source:
Knopman, J. M., Krey, L. C., Oh, C., Lee, J., McCaffrey, C., & Noyes, N. (2014). What makes them split? Identifying risk factors that lead to monozygotic twins after in vitro fertilization. Fertility and sterility, 102(1), 82-89.
