By the time you and your doctor have decided in vitro fertilization (IVF) is most likely your best course of action to conceive, you’re eager to get pregnant and want to do all you can to increase your chances of conceiving. While it may seem like transferring more than one embryo would give you a greater chance of a successful IVF cycle, you may not be looking at the big picture. In this blog, we will review what factors are used to decide how many embryos to transfer to not only help you conceive but to also provide you and your baby the best possible chances of a happy and healthy pregnancy!
How Many Embryos to Transfer: The IVF Process in General
According to Resolve: the National Infertility Association, IVF is “a technique where a woman’s eggs and man’s sperm are combined in a special laboratory in order to create an embryo and/or embryos. The embryo and/or embryos are transferred to the woman’s uterus through her cervix to enhance the chances of pregnancy.” Every protocol including your fertility treatment, what medication is recommended for you, and how many embryos to transfer are based on numerous factors such as whether you or your partner have any diagnosis that may impact your fertility and the age of the woman trying to conceive.
Once your protocol has been determined based on your history, age, consultation and fertility assessment; a nurse, IVF coordinator or your doctor will review your IVF protocol and corresponding medication list. ou would then begin to take injectable hormones to stimulate follicular growth in order to produce more eggs. You will be monitored closely during this time and once your doctor feels your follicles have grown to a certain size indicating that the eggs are mature enough to be fertilized, he or she will advise you to take the trigger shot. You will be scheduled for the egg retrieval 36 hours after the trigger shot and after the eggs are retrieved, the eggs and sperm will be combined in a lab to create embryos.
How Many Embryos to Transfer: Age is a factor
Single embryo transfer, known commonly as, eSet (for elective Single Embryo Transfer) is recommended as it’s safest for both mother and child. Mothers of twins are about two and a half times more likely than those of singletons to have pre-eclampsia and multiples, can often end up in the NICU. However, when it comes to deciding how many embryos to transfer, the Society of Assisted Reproduction (SART) and the American Society of Reproductive Medicine (ASRM) offer suggested guidelines based on a woman’s age.
In general, how many embryos to transfer can increase in relation to a women’s age as there is a decline in fertility the older a woman becomes. This means that if a patient who is under 35 years old asked her doctor how many embryos to transfer, her doctor might recommend eSet. If the patient is over 40 years old and she has not had her embryos screened for chromosome errors with PGT-A, her doctor may recommend transferring two embryos.
How Many Embryos to Transfer: How to Increase Your Success
Another factor that can come into play when deciding how many embryos to transfer is whether genetic testing like, \ Pre-implantation Genetic Testing for Aneuploidy (PGT-A), formerly known as PGS was utilized on your embryos. PGT-A is utilized to select embryos that are chromosomally normal for a future embryo transfer. Chromosomally normal embryos have an increased chance of resulting in a healthy, ongoing pregnancy compared to abnormal embryos. Testing of the embryo is done by taking a small biopsy of the embryo. The embryos are frozen after the biopsy and chromosomally normal embryos are later transferred once the results are available. Transfering a chromosomally normal embryo reduces the chance of miscarriage or an unsuccessful transfer.
As you embark on your IVF journey, there are many things to consider but while how many embryos to transfer is one, how it relates to the health of your child and your pregnancy should always be paramount!