In vitro fertilisation, or IVF, is the most well-known and successful fertility treatment available for most people suffering from infertility. For anyone considering embarking on IVF, it is a major life decision involving emotional, financial and organizational considerations. It’s therefore crucial to know what to expect. Most of us understand that IVF consists of a series of steps, or a course of treatment, rather than being a one-off event. The question is, how many cycles of IVF does it take to get pregnant? In other words, what can you expect before achieving your goal?
In this IVI blog article, we explain what we mean by a cycle of IVF and some of the factors that can impact on your chances of success. We also take a look at some statistics to help you make a judgement about how many cycles you should plan for.
What is a cycle of IVF?
An IVF consists of several stages. These always follow the same pattern, but it’s worth remembering that there is no guarantee the cycle will be completed. It’s possible that your ovaries will not respond as expected to the first step of ovarian stimulation. In this case the cycle could need to be abandoned and a new cycle started at the right time. These are the steps:
- Ovarian stimulation with the aim of getting your ovaries to produce multiple oocytes.
- Egg retrieval after the oocytes have reached an adequate number and maturity.
- Fertilization in the laboratory in order for conception to take place.
- Culture and observation of the resulting embryos as they develop in the laboratory.
- Transfer of a selected embryo to your uterus, hopefully to be followed by implantation and pregnancy.
The whole process from start to finish takes around three weeks, followed by a two-week wait after transfer to test whether you are pregnant.
Frozen embryo transfer
However, there is an important additional option missing from our summary above. If your egg retrieval and fertilization resulted in more than one good quality embryo being available, the remaining embryos are cryopreserved. This way, they can be thawed and used for another attempt if the first one is not successful, or later when you want to extend your family. These subsequent attempts would be a good deal quicker than the initial round, because they omit the ovarian stimulation phase. In a frozen embryo transfer, there is a period of about five days during which your uterus is prepared for reception of an embryo, followed immediately by transfer.
One cycle could include several embryo transfers
One cycle of IVF could, therefore, if several good quality embryos have been produced, encompass several embryo transfers. Why is there a slight obscurity about whether a cycle means an egg retrieval or a single embryo transfer? Perhaps this is because in the early days of IVF, fresh embryo transfer was the only option available. Therefore one cycle meant one egg retrieval and one corresponding embryo transfer. Now, since the development of embryo freezing and cryopreservation techniques, maybe the technology has overtaken our terminology. Perhaps in the future we will start to think about a ‘round’ or ‘cycle’ of IVF as an embryo transfer rather than the original ovarian stimulation. However for now we are sticking with a cycle being the full process.
Consistency of success statistics
The difference may seem trivial, but it’s important, from the point of view of collating statistics, that clinics and national bodies are comparing like with Like. At IVI, we deal with this potential ambiguity by making it clear in our published success rates that we are reporting on success per cycle, including all available embryos from that cycle. In our detailed statistics, we are able to analyze by embryo transfer and many other variables.
What are the factors that impact on IVF success?
Of course, IVF results are not just a question of numbers. It is true that overall, the higher the number of IVF cycles, the higher the success rates. However, there are other factors that come into play. These include the reason for infertility in a particular patient, their fertility and general medical history, and their BMI. But far and away the most important factor for a woman using her own eggs is age. For IVF using egg donation, the age of the recipient is much less relevant.
What do the statistics tell us about IVF success?
The statistics clearly show us both that age is an important factor in success rates. The more attempts, the higher the success. A success rate of say 67.2% on the first cycle (if you are aged between 35 and 39) may look a little disheartening, until you remember that even for young and healthy people with no fertility issues, the chance of natural conception in any given monthly cycle is only around 20%. We have no problem with the idea of keeping on trying when it comes to natural conception. Generally speaking, the same idea applies to conception and pregnancy through IVF treatment. Here are our IVI results per age group and per number of cycles:
- Age under 29: cumulative pregnancy rate 79.8%
- Age 30 – 34: cumulative pregnancy rate 75.9%
- Age 35 – 39: cumulative pregnancy rate 67.2%
- Age 40 – 44: cumulative pregnancy rate 59.2%
The accumulated pregnancy rate includes the gestation after transfer of fresh embryos and the surplus cryopreserved embryos generated in a cycle.
At IVI, the chances of getting pregnant with an IVF increase the more attempts you make.
- Overall success rate first attempt: 68.8%
- Overall success rate second attempt: 85.7%
- Overall success rate third attempt: 95.1%
These figures apply to IVF for women who use their own eggs. With the use of donated eggs, the overall success rate is even higher at 99.3% by the third attempt.
IVF success rates for IVI clinics
There is of course no easy answer to how many IVF cycles you need to get pregnant. It could be one cycle for nearly 69% of our patients, or it could be two or three cycles. Everyone is a unique case. One of the reasons for our outstanding statistics is that we personalize the hormonal stimulation phase of the IVF cycle individually to secure the best results. We also have the most advanced IVF laboratories for the development and selection of embryos under optimum conditions.
If you’d like to know more, or discuss your concerns with us, do get in touch. There are no guarantees, but with 9 out of 10 of our patients achieving their dream of holding their own baby in their arms, the chances are good!
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