Many hopeful parents dream of welcoming twins — two babies born together, sharing the same start in life. For couples undergoing IVF in Bangkok, this question often arises: Does IVF increase the chances of having twins?
IVF (in vitro fertilization) is a form of assisted reproduction that has been closely linked to the conception of twins. It is not uncommon for patients who undergo this procedure to request their doctors to arrange for such multiple births. But is this something that can be orchestrated, and is it safe?
At Bangkok Central Clinic, our fertility specialists explain how IVF works, when twin pregnancies may occur, and what medical and ethical considerations come with it. While modern IVF technology can occasionally result in multiple pregnancies, the focus always remains on achieving a safe, healthy, and successful pregnancy.
Understanding How Twin Pregnancies Happen
Twins occur in two main ways:
- Fraternal (non-identical) twins: Two separate eggs are fertilized by two different sperm. This is more common with IVF, as multiple embryos may be transferred.
- Identical twins: A single embryo splits into two, creating IVF identical twin embryos. This happens naturally and cannot be controlled or predicted, even with advanced fertility technology.
While IVF can influence the number of embryos transferred, it cannot directly determine whether an embryo will divide and result in identical twins.
Does IVF Increase the Chances of Having Twins?
The answer is not quite clear-cut. When undergoing IVF treatment, a woman’s ovaries are stimulated to produce many eggs. When matured, these eggs are retrieved and mixed with healthy sperm from the male partner or donor. This allows fertilization to occur and embryos to develop.
After genetic testing to identify healthy embryos, a select few are transferred into the woman’s uterus in hopes of successful implantation that will confirm pregnancy. The trend has been to transfer more than one embryo into the woman’s uterus, especially when there is a higher risk of the treatment failing due to such factors as the woman’s age or a history of failed IVF treatments. The idea that prevailed was that by implanting more than one embryo, a woman was likely to at least have one successful implantation.
However, this policy resulted in a higher-than-usual rate of multiple pregnancies for women who conceived through IVF. The birth of twins rose by about 72% between 1980 and 2018. Non-identical twins are the most common type of multiple pregnancy that occurs with infertility treatments.
Some countries are now limiting the number of embryos that can be transferred in a single cycle of IVF treatment. This change in regulations has seen a drastic reduction in the number of multiple births from assisted reproduction procedures. A few countries, like the UK, will allow no more than two embryos to be transferred for women under the age of 40 and no more than three embryos for women over this limit. In the US, the American Society for Reproductive Medicine (ASRM) has issued guidelines for single embryo transfers (SET) for women with a good prognosis under the age of 35 years.
Other countries have no strict regulations in place, with IVF clinics setting their own standards. There is also no assurance that a doctor will adhere to the upper limit set by regulators. Some prefer to stick to single embryo transfers to avoid the risks associated with a woman undertaking multiple pregnancies.
Embryo Transfer and the Chances of Twins
While IVF treatment may increase chances of having multiple births, it technically depends on how many embryos you are allowed to have transferred, whether the specialist is willing to abide by the legal limit, and if successful implantation of all the embryos occurs. So while IVF has resulted in an increased rate of twin births, there is no assurance that even with multiple embryos transferred, you will conceive and birth twins.
Whether you have a single or multiple embryo transfer, your chances of successful implantation and carrying the child to term may hinge on other factors as:
- Age of the mother
- Embryo development at the time of transfer
- Success rate of the mother with IVF treatments
- Whether the mother has previously conceived and given birth naturally
- Cause of infertility
- Lifestyle and health risks of the mother
Why Twins Are Desirable for Some Couples
Having twins can seem like a double blessing for many couples pursuing fertility treatment. It means one successful cycle could lead to the complete family they hoped for. In some cultures, twins are an alluring prospect for anyone undergoing fertility treatment as they represent the promise of double the luck.
Parents may prefer this outcome for several reasons:
- IVF can be physically and financially demanding; twins can reduce the need for multiple treatment rounds
- Some parents want their children to grow up close in age
- For older couples, a twin pregnancy may feel like a time-saving advantage.
Yet, fertility experts carefully weigh these preferences against medical safety. The more embryos transferred, the higher the risk of complications. So while there may be some merit to wanting to conceive multiple babies, there are associated risks that have pushed the medical fraternity to set limits on embryo transfers. Many countries, including Thailand, now recommend limits on embryo transfers to generally one or two embryos per cycle, depending on the patient’s age and fertility prognosis.
At Bangkok Central Clinic, embryo transfer decisions are made collaboratively with each patient. Our specialists use advanced genetic testing and embryo grading to maximize success while minimizing risk.
Risks of Twin Pregnancies with IVF
While twin pregnancies can be joyful, they also carry increased risks for both mother and babies. Carrying more than one fetus comes with a higher risk of certain complications, including:
- Preeclampsia: A condition in which the mother’s blood pressure becomes elevated, resulting in her suffering life-threatening complications such as seizures and stroke.
- Gestational diabetes: More common in women with multiple pregnancies, increasing the risk of larger babies, underweight or premature birth, and children developing respiratory complications due to inadequate oxygen and nutrients reaching the fetuses.
- Preterm birth: Twins are more likely to be born before 37 weeks, which can cause respiratory and developmental challenges.
- Low birth weight: Twins often weigh less than singletons, increasing the risk of neonatal complications.
- Placental and delivery complications: Limited nutrients and space can affect fetal growth and cause preterm labor.
- Disability: At a higher rate, occurring in as much as 25% of births where the child is born weighing less than 2 pounds.
These factors are why many fertility specialists now aim for single healthy embryo transfers rather than intentionally pursuing twin pregnancies.
Safe Pregnancy with IVF at Bangkok Central Clinic
While having twins would be a wonderful outcome for hopeful parents undergoing IVF, it is not a goal fertility specialists pursue. At Bangkok Central Clinic, our goal is to help you achieve a healthy pregnancy, not necessarily multiple births. Every IVF cycle is designed to optimize implantation success and minimize complications. Every effort is made before embryo transfer to ensure that the highest quality embryos are selected, which will increase chances of implantation.
Before embryo transfer, our team:
- Conducts comprehensive fertility assessments for both partners
- Uses genetic and chromosomal testing (PGT or NGS for IVF in Bangkok) to identify healthy embryos
- Monitors uterine and hormonal conditions to select the optimal timing for transfer
- Provides personalized support and follow-up care throughout pregnancy
While it is natural to be curious about twins, our specialists emphasize safe, successful pregnancies. Book an appointment to consult our fertility experts about the path to parenthood that is most suitable for you.
Contact us via Line: @bccivf, WhatsApp: 0644799538, 0953641949, and WeChat: BCCIVF.
Frequently Asked Questions
What are the chances of having boy-and-girl twins with IVF?
Fraternal twins (one boy, one girl) may occur when two embryos of different sexes implant successfully. Embryo gender testing in Bangkok (PGT-A) can identify embryo sex before transfer, though regulations vary by country.
Is it safe to have twins through IVF?
While twins can be safely delivered, they carry a higher risk of preterm birth and maternal complications. Your fertility specialist will guide you toward the safest approach for your health and your babies.
