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The Benefits of Frozen Embryos Over Fresh Embryos for IVF

If you and your partner have been having trouble conceiving, you’ve no doubt done some research into what opportunities are available to you. For many couples, in vitro fertilization provides the solution needed to start their families. As you may know, in vitro fertilization is the most popular assistive fertility treatment in the world. It accounts for 99% of such procedures and about 1.5% of babies are born via IVF.

The success rate of in vitro fertilization is influenced by a number of factors, just like a natural conception would be. Everyone responds differently to things and there are ways to bolster the odds of success. The typical in vitro fertilization procedure has about a 50% success rate. If this seems low to you, keep in mind that the probability of natural conception for the typical fertile couple isn’t terribly higher.

When talking about in vitro fertilization, it’s important to understand the details of the procedure and what decisions will be made throughout the process. One such important detail is the use of different kinds of embryos. Or, rather, the different ways embryos are handled. When talking about IVF, the discussion often comes up about the benefits of using frozen embryos in comparison to fresh embryos. One’s initial reaction might be that fresh embryos have to produce better results because we often associate “new” as better. But, that’s actually not the case when it comes to IVF. It turns out frozen embryos are actually the preferred choice. Here is what you need to know about embryo storage and IVF procedures.

IVF and the usage of embryos

It would be helpful to give a brief explanation of the IVF process and how embryos play a part in it. Whether you’re using your own eggs or a donor’s, the actual fertilization will take place outside of the body and in a lab. Once there is a viable embryo, it is then introduced into the woman’s body where it will hopefully be carried through a healthy pregnancy.

That’s the simple description of what IVF is. One key part to keep in mind, though, is the hormonal treatments and ovary stimulation that takes place if it’s your eggs that will be removed for fertilization. In order to bring eggs to maturation quickly, this stimulation is required. Once it’s determined the eggs are ready for the next phase, they are surgically removed. This is a minor surgery, however, and twilight anesthesia will be employed. It’s important to note this because that hormonal treatment is one of the factors that can contribute to fresh embryo vs frozen embryo success rates as we’ll see shortly.

Fresh embryo usage

The hormone treatment process outlined above would be followed by a fresh embryo transfer in the days following the initial egg removal procedure (typically within three to five days). Otherwise, the embryos are frozen for usage at a later date. Fresh embryo transfers have been in use for decades and clearly there is a satisfactory level of success since they are still performed.

There are acknowledged benefits of opting for fresh embryo transfers over frozen. The primary one is that, assuming you have success with this first attempt, you won’t need to go through another round of stimulation therapy at a later date. With frozen embryos, there is still a need for mild hormone therapy in order to properly prepare the body for the introduction of the embryo. So, you could be looking at going through treatment twice, once for producing the embryos (ovarian stimulation and egg retrieval), and the second for the actual transfer of the embryo(s) (frozen embryo transfer cycle). However, it’s important to note that the second treatment, which involves the preparation of the uterus for implantation, is much milder in comparison to the initial ovarian stimulation. However, since hormone treatment can be expensive and individuals respond differently to it, only going through hormone treatment once can be considered a big benefit to many.

Why frozen embryos yield better results

Certain clinical situations require freezing of embryos to avoid a fresh embryo transfer. For example, if a patient is at risk of ovarian hyperstimulation syndrome (OHSS), all embryos are frozen to avoid a fresh embryo transfer and exacerbation of the syndrome. If the uterine lining is suboptimal for implantation during the stimulation of the ovaries, all embryos are frozen, and at a later date the uterine lining is optimized during a frozen embryo transfer cycle. Additionally, if a couple chooses genetic testing of the embryos with preimplantation genetic screening and/or diagnosis (PGS/PGD), embryos are frozen to allow time for the genetic testing. Even without any of the above clinical indications for freezing, as far as successful treatment goes, frozen embryos do perform better than fresh ones. Again, hormones are an important factor. It is believed that because frozen embryos would be used long after the egg stimulation hormone therapy is done, the woman’s body would have returned to a natural state hormonally speaking. This better mimics the natural conception process which can yield a higher chance of success. Specifically, recent studies have shown better implantation rates, better live birth rates, higher birth weights, lower miscarriage rates, and lower ectopic pregnancy rates following frozen as compared with fresh embryo transfers. Additionally, being able to plan ahead with the use of frozen embryos allows the woman to undergo the embryo transfer procedure at the ideal time.


Few things are as emotionally trying as being unable to conceive. At California Center of Reproductive Health, we understand that. That’s why we are dedicated to providing you with the care you need to start a family of your own. If you’ve been having difficulty over the past year getting pregnant, contact us today to schedule an appointment. Our team is here to help you identify a reason for your difficulties and provide the treatments necessary to overcome them.