IVF (In vitro fertilization) is a boon that has helped many couples realize their dream of parenthood. While most couples prefer one baby, some couples will want to have twins either because their medical condition won’t allow for another pregnancy or because they want to have two babies.
Whatever the reason, IVF has made it easier for them to have twin babies. The advanced medical technology allows parents to decide how many babies they want and transfer embryos accordingly. In this article, we’ll look into detail your chances of having a twin baby through IVF.
Chances of Having Twins With IVF
The chances of having twins have increased greatly today, thanks to the IVF procedure that allows doctors to place two embryos into the uterus for implantation. If both embryos are successfully implanted and start developing, couples can have a twin pregnancy.
A study done recently shows that about 25–30% of IVF pregnancies are twin pregnancies. This depends on the number of embryos transferred and the number of embryos that successfully implant and start developing in the uterus.
What is the Probability of a Twin With IVF?
According to the Human Fertilization and Embryo Authority, one out of five IVF pregnancies are twin pregnancies or multiple births. This happens because fertility doctors usually transfer more than one embryo into the uterus to increase the chances of pregnancy.
The doctors believed that even if most of the embryos died, at least one could successfully make it to the end (childbirth). Twin pregnancy happens when two of those embryos implant in the uterus.
How can Twin Pregnancy Happen in IVF?
There are two ways twin pregnancies can happen in IVF.
1. When fertility doctors transfer two or more embryos into the uterus
Sometimes, to increase the chances of pregnancies, fertility doctors will transfer more than one healthy embryo into the uterus. If two of those embryos implant and start developing, it can lead to twin pregnancies. They are called dizygotic twins.
However, there is one downside to this method: multiple pregnancies. Multiple pregnancies happen when more than one or two embryos implant and start developing. This can be unhealthy for both the mother and the embryos. So, most doctors don’t transfer more than two embryos in a single cycle.
2. When one embryo splits and develops into two separate babies
This type of twin pregnancy happens when one embryo splits and develops into two babies. These babies are called identical twins or monozygotic twins. That is, they developed from a single zygote (embryo).
What if I Want to Have a Twin Pregnancy with IVF?
Though doctors don’t transfer multiple embryos to avoid multiple pregnancies, you can choose to have two embryos transferred if you want to have twins. You might want to have multiple embryos transferred for various reasons. Some of them are listed below.
- You are getting old and want to increase your chances of pregnancy.
- IVF is expensive. You might want to succeed in a single attempt to avoid undergoing another cycle.
- You might genuinely wish to have twin babies.
You can discuss this with your fertility doctor and assess your chances of having a successful twin pregnancy before proceeding with it. Some women’s bodies won’t be able to carry twin babies till childbirth. So, understand your body condition before deciding to have twins.
Though some couples might prefer to have twin babies, doctors usually don’t recommend it as it can lead to complications for both the mother and child. This is especially so if the female has any existing health conditions. Below are some of the risk factors of an IVF twin pregnancy.
1. Gestational diabetes
Gestational diabetes is a diabetic condition that develops during pregnancy. This condition can affect the baby and cause it to be larger than normal in size. This can cause injury to you and the baby if you have a vaginal birth. It can also lead to other complications like breathing difficulties in babies, jaundice, seizures, etc.
Pre-eclampsia is a condition where pregnant women have high blood pressure (hypertension), swelling in the body, and excess protein in the urine. This happens when the placenta is not developing properly due to a problem with the blood supply.
3. Preterm birth
According to studies, about 60% of twin births are premature, and 12% are delivered before 32 weeks. This can increase complications in the baby and can be fatal to some.
4. Cesarean (C-section)
Twin pregnancies also increase the need for C-sections. This can cause hemorrhaging during or after the procedure and also takes longer to recover than natural births.
5. Low birth weight
This is common in twin pregnancies, whether it is a natural or IVF pregnancy. According to studies, most twin babies weigh less than 2.5 kg during birth. Some babies even weigh less than 1.6 kg if they are delivered before 32 weeks.
These babies have a high risk of having breathing, vision, hearing, and heart problems. Some might even get cerebral palsy.
6. Twin-Twin Transfusion Syndrome (TTTS)
This happens in twins who share a single placenta, where one baby has excess blood flow, and the other one has low blood flow. This has been found to happen in about 10% of twin pregnancies.
7. Intrauterine Growth Restriction (IUGR)
IUGR occurs when one or both babies do not grow at the rate they should. This delay in growth rate can affect their development and lead to health issues in one or both babies.
Factors that Increase Your Odds of Having Twins Naturally
Though IVF treatment is one of the best ways to conceive twins, there are many couples who naturally conceive twins. There are certain factors that increase the odds in their favor. Let’s look at some of those factors.
Some say that having twins is hereditary. This fact is partially true. Your chances of having twins increase if you are a twin yourself or if someone from your family are twins.
This is mainly due to hyperovulation, a condition where a woman releases more than one egg during ovulation. It has been shown that hyperovulation can be hereditary and passed from mother to child. Thus, your genetics can increase your chances of having twins to some degree.
Women over the age of 35 have been shown to have a higher chance of conceiving twins. This is due to the hormonal changes that occur in their body as they near menopause.
Height & weight
A research conducted between tall and short women proves that taller women have a higher chance of having twins.
Women who are overweight or obese have also been shown to have a higher chance of conceiving twins. This is specifically the case if their BMI is over 30.
Your previous pregnancy can also play a part in your having twins. According to a study, a 35-year-old woman who already has 2–3 kids has a higher chance of having twins than a 20-year-old woman with no kids.
While having twins can be a good thing if you can’t or don’t want to be pregnant again, your health and body condition also matter here. So, before deciding on having twins through IVF, have a detailed discussion with your doctor and learn all its pros and cons.
Though having twins is not a serious issue, some couples might not want to have twins either as a personal preference or because their body condition doesn’t allow it. If they don’t want to have twins through IVF, they can request the doctor only to transfer one high-quality embryo during the embryo transfer.
Though this is not the case for most couples, some people have a higher chance of having twins through IVF. This is because fertility doctors usually transfer two embryos into the uterus to increase the chances of pregnancy. Twins happen when both embryos implant and start developing in the uterus.
On average, the chances of twins with IVF are around 25%. This depends on the number of embryos transferred and the number of embryos that successfully implant and start developing in the uterus.