Deciding whether to transfer 1 or 2 embryos

Your fertility journey includes assisted reproductive technology, like IVF. That’s why you’ve clicked on this page. You’ve got a lot to consider. You’re going through the logistical planning of when to take your medication, running from the lab to get bloodwork done and then back to work, and while you’re in the midst of this you’re wondering,

Should we transfer 1 or 2 embryos?

You’re probably considering 2 embryo transfer because of your age, because you’ve had multiple failed frozen embryo transfers (FET), or because you’re deciding this with your surrogate.

Then you start wondering about what that could really mean — twins!

But first, this. Transferring 2 embryos instead of 1 does not double your chances that you’ll get pregnant. When you transfer 2 embryos with ICSI (Intracytoplasmic Sperm Injection) your chances of having even 1 of the 2 embryos successfully implant is not significantly higher than a single embryo transfer (SET), according to an Oxford study (Hannu Martikainen, 2001).

Second, it might not be your decision to make. Your fertility doctor and/or clinic may only allow you to transfer 1. They might have a policy and you might not qualify. If it is or you’ve moved to a clinic that does offer this choice, then it’s decision time.

Should We Transfer 1 or 2 Embryos

The impact of this decision could lead to a different family make-up and a host of other impacts. It is your personal decision to make (plus potentially your partner and perhaps another child). You know best. And here are some considerations to help you decide if you want to increase your chances of twins.

Two chances in one transfer. With two chances in one transfer you could view this as a pro and a con. You have more to gain with 2 babies, but more to lose than an SET. If it fails, then you fail doubly because you’ve lost two precious embryos and two potential attempts. Whereas with an SET times 2, you have twice the attempts. If the transfer fails the first time it gives your fertility doctor a chance to change up the protocol or do an ERA if you haven’t already, or change your overall health such as diet, and increase your odds of a successful transfer the next time. Remember, your odds of pregnancy don’t increase much by doing a 2 embryo transfer.

Your fertility doctor’s advice. This is of course an important consideration due to their knowledge of your case and their expertise. You’ll get their thoughts on your overall health and situation.

Fun fact, multiples (e.g. twins, triplets) are slightly more common with IVF even when you do an SET. Talk to your doctor about your chances.

Age. If you or the woman attempting pregnancy is 35 or older then you’re considered a geriatric pregnancy, which comes with some increased risks in pregnancy and delivery, regardless of whether you have a singleton or multiples. A twin or triplet pregnancy automatically labels you a high risk pregnancy. Adding both these risks together is something to consider.

Increased age may also mean you want to just go through the one pregnancy and have a sibling in one shot and not have to go back later to try for a sibling when you’re even older. This may be a consideration based on your overall health and energy level as you age.

One pregnancy = 2 children. This is an obvious consideration. If all goes well, it’s like a two-for-one deal where one successful transfer and one pregnancy produces two children. This may reduce your total number of egg retrievals and transfers. Only going through egg retrieval once or one fewer attempts may cut down on the physical and mental anguish and time and costs.

That said, a pregnancy with multiples may be interpreted as much more difficult than carrying a singleton and the comparison is not equal.

Some lower financial costs. If you have to go through fertility treatment fewer times because you don’t need to go back to do another egg retrieval or FET to try for a sibling, then you may save those costs.

Some increased financial costs. Yes, this contradicts the above consideration. If you were planning to have two children added to your family and have twins over a singleton and then another singleton, then you can’t rely on passing down baby and children stuff. If you have different aged children you’d have second hand supplies to pass down to the younger sibling. With twins it costs more because you have to buy, borrow or acquire two of everything such as cribs and car seats. No hand-me-downs for your twins, most likely.

But these days there are a lot of ways to get free or discount baby and children supplies, especially among parents who have multiples who pass down to other parents of multiples. This depends partly if you live in a major city.

Hands-on support. If you have a network of family and friends who will (be in your bubble and) be there to help you from day one of the kids’ birth to when they’re 3 to 5 years old, that means a lot. Twins are challenging to care for, especially in the first few months. It’s more than twice the work. You’ll need to create a built-in support network to get through the long days and share in the good days too.

Each child has a companion. With twins your children have a built-in best friend. It doesn’t mean they’ll always be besties and that they will stay close, but as babies and children they socialize and learn from one another. Twin relationships are unique.

Advice from someone who has twins or triplets. Anyone who is considering transferring 2 or more embryos or undergoing fertility treatment that increases the odds of multiples should talk to someone who has twins or triplets who are age 3 or older. Learn from their experience.

Health risks. There are increased risks for both the mother and the newborn for women who are pregnant and deliver twins:

  • For babies born via IVF, twins are 12 times more likely to be born prematurely, 16 times more likely to have low birth weight, and approximately five times more likely to have jaundice or respiratory complications than singletons. (Sazonova et al.’s 2013 study)
  • There’s significantly higher rates of pregnancy complications, including preeclampsia and cesarean sections, for mothers of twins conceived via IVF versus mothers of singletons conceived via IVF. (Sazonova et al.’s 2013 study)
  • Carrying multiples increases the risk of “pregnancy-induced hypertension, gestational diabetes, peripartum hemorrhage, operative delivery, and postpartum depression and anxiety.” (El-Toukhy, 2018)
  • A twin birth has a six fold increased risk of pre-term births, which is a leading cause of infant mortality. (El-Toukhy, 2018)

Potential for triplets. The risk is very low, at about 1%, but one of the embryos could split and you have triplets.

Twice the love. The rewards are huge. You get twice the love, twice the kisses and twice the rewards if you have twins. That’s a factor to weigh in heavily.

It’s a personal choice whether this factor rules over all the other considerations.

Whether you transfer one or two or more, may the decision be smooth and your transfer be successful. Good luck!


El-Toukhy  T, Bhattacharya  S, Akande  VA. Multiple pregnancies following assisted conception. BJOG 2018;125:12–18.

Hannu Martikainen, Aila Tiitinen, Candido Tomás, Juha Tapanainen, Mauri Orava, Leena Tuomivaara, Sirpa Vilska, Christel Hydén-Granskog, Outi Hovatta, the Finnish ET Study Group, One versus two embryo transfer after IVF and ICSI: a randomized study, Human Reproduction, Volume 16, Issue 9, September 2001, Pages 1900–1903.

Sazonova A, Källen K, Thurin-Kjellberg A, Wennerholm UB, Bergh C. Neonatal and maternal outcomes comparing women undergoing two in vitro fertilization (IVF) singleton pregnancies and women undergoing one IVF twin pregnancy. Fertil Steril. 2013 Mar 1;99(3):731-7. doi: 10.1016/j.fertnstert.2012.11.023. Epub 2012 Dec 7. PMID: 23219009.

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