When my husband and I first started our IVF journey, peoples’ response was often, “That’s so exciting; you’re going to have twins!” I quickly got very frustrated, explaining to them that there was actually a very small probability that would happen for us. While it is true that IVF has produced many multiples, the bigger issue that I really want to raise awareness about is that doing IVF does not guarantee you a baby, let alone twins.

The truth is, some couples go through many rounds of IVF egg retrievals without getting any viable embryos. So far on our journey, this has been our experience. FertilityIQ, a fantastic resource for understanding fertility issues, estimates that only 40% of couples will have success after a single IVF cycle. This increases to about 70% after three cycles. So far, my husband and I have undergone five IVF cycles without ever achieving a genetically normal embryo.

Most people do not understand all of the intricacies of how IVF works. FertilityIQ offers a detailed summary of the process, but very simply, a woman undergoes a period of ovarian stimulation where she is given a specific combination of fertility medications for roughly 10-12 days (this could be more or less depending on the situation) to stimulate her ovarian follicles to release an increased number of mature eggs. Those eggs are then retrieved, or collected, and removed from the woman’s body.

The retrieved eggs are then fertilized with sperm in a medical lab, and if the eggs successfully fertilize, they are then cultured and monitored while they grow. The cells of the embryo should continue to multiply until the embryo becomes a blastocyst. It’s at this stage that an embryo is ready to be transferred into a woman’s uterus in what is considered a fresh transfer; or, the embryo is frozen to be transferred at a later date. An embryo might be frozen for a variety of reasons, one of which is to be genetically tested for chromosomal abnormalities.

What most people don’t know is that IVF is not a guarantee, and in every step of the process eggs or embryos can be lost. A friend of mine refers to this drop-off as the IVF Hunger Games: may the strongest embryos win. In a ‘natural,’ or non-stimulated state, generally speaking, only one mature egg is released during ovulation; but when stimulated, several eggs can be retrieved when ovulation is triggered. The number of eggs retrieved can vary significantly depending on the woman. I, for example, at age 43 have never retrieved more than 5 eggs, while I have friends that have retrieved as many as 30 or 40 eggs in a single cycle. Every woman is different.

In order for eggs to fertilize, they must be mature. It’s not a guarantee that all eggs will be mature, nor is it a guarantee that all eggs will fertilize. Early in our journey, we struggled with fertilization. After our first two egg retrievals, only one egg fertilized each time. This is an extremely low fertilization rate. During our last two cycles, we were able to improve fertilization by adding a calcium ionophore solution for oocyte activation, as well as upgrading from Intracytoplasmic Sperm Injection (ICSI) to Physiological ICSI (PICSI). This resulted in a remarkable 100% fertilization of all of our mature retrieved eggs.

FertilityIQ estimates that, on average, 70% of retrieved mature eggs will fertilize. For eggs that do fertilize, there is then about a 40-50% probability that an embryo will grow into a blastocyst and a 20 to 50% probability that the blastocyst will be genetically normal. These numbers can vary significantly. For us, because of my age, I have been diagnosed with poor egg quality. This means we have a significantly higher chance of a genetically abnormal embryo, with only a 5 to 10% chance of an embryo being genetically normal. For us, it’s definitely not a guarantee that IVF will produce a baby.

If you are fortunate enough to have embryos make it to the blastocyst stage, you can delay the embryo transfer to have the embryos genetically tested. The embryos are frozen and biopsied to see if they are chromosomally or genetically normal using preimplantation genetic screening (PGS), preimplantation genetic testing for aneuploidy (PGT-A), or comprehensive chromosomal screening (CCS). A large number of miscarriages are thought to be caused by genetically abnormal embryos. By doing PGS/PGT-A/CCS you are able to determine if an embryo has the correct number of chromosomes and is thus considered viable, leading to a higher possibility of a successful pregnancy.

At both of the fertility clinics where we have done IVF, the protocol is to only transfer one embryo if it has been tested and found to be genetically normal. It’s only in cases where embryos are not tested that they will transfer multiple embryos--usually two or three depending on the age of the patient. In many cases, multiple embryos are usually transferred on the assumption that not all are genetically normal. There are a number of risks with pregnancies of multiples, which is why many clinics choose to focus on a healthy pregnancy with just one baby. So, contrary to popular belief, IVF does not always equal twins.

Even with a genetically normal embryo, there is still no guarantee that it will result in a live birth. FertilityIQ states that there is a 60-70% success rate with a genetically normal embryo. While the success rate is significantly higher than that of a non-genetically tested embryo, it is still not 100% that the embryo will implant into the uterus.

With a frozen embryo transfer, women are given drugs to suppress their ovaries to prep the uterus for optimal implantation. Every woman is different, and the protocol for preparing the uterus for optimal implantation is not always the same. The lining of the uterus must be a certain thickness, ovaries must be in a neutral state, and reproductive organs must be free of cysts or polyps. The window for implantation is short, and it does not happen at the same time for every woman. The receptivity timeframe for when a woman can optimally receive an embryo to be successfully implanted can also vary. Failed embryo transfers are still quite common.

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I have a number of friends who have had failed transfers with genetically normal embryos. In many cases, there is no answer as to why the transfer failed. There are tests, including an Endometrial Receptivity Analysis (ERA), that can determine the optimal time to transfer an embryo to help increase the probability of implantation, but sometimes, even if everything is perfect -- the embryo and the environment -- the transfer can still fail.

For my husband and I, after five failed rounds of IVF yielding no genetically normal embryos, the odds are not in our favor, but we remain optimistic. We will try one more cycle, and while there are no guarantees that IVF will work for us, we remain hopeful.

I don’t share these statistics to scare anyone, but rather to educate those who are supporting friends or family through an IVF journey on the realities of IVF. While many see IVF as an exciting step for a couple on their journey to becoming parents, there are a lot of things that have to go right in order for an IVF cycle to result in a baby. IVF is also expensive, stressful, all-consuming, and for many people, it is their last hope at their own biological child.

IVF does not always equal a baby, and my hope moving forward is there will be increased awareness and education of the risks and statistics associated with IVF so that those undergoing treatments can feel less misunderstood and more supported.

Maiclaire Smith shares her IVF journey on Instagram at @prequeltoparenthood and on her blog, Prequel to Parenthood.