A natural cycle IVF can be successful, but it typically has lower success rates compared to stimulated cycle IVF. Also, it does have higher cancellation rates. In the natural cycle of IVF, the woman’s body ovulates naturally without the use of fertility medications. This approach can be less invasive and more affordable, but it also has limitations.
Here are some factors that can affect the success of natural cycle IVF:
If you’re considering natural cycle IVF, it’s important to discuss the potential benefits and drawbacks with your fertility specialist. They can assess your situation and determine if this approach is suitable for you.
In some cases, a combination of natural and stimulated cycles may be recommended. This can help increase the chances of success while minimizing the risks and side effects of hormone stimulation. We do use double stimulation cycles in women with poor ovarian reserve, but what is the best protocol, that always depends on a personalised approach.
A variation of IVF is natural IVF. When we say natural IVF, we mean IVF in a natural cycle, which means that we monitor the development of a follicle, and when the follicle is ready, we trigger ovulation, and we usually collect one egg. The chances of success as a general rule in a natural IVF are lower than in a medicated IVF.
Does it make sense to do it? Yes, it does. Usually, of course, natural IVF plays a role when a person cannot take injections, medication to stimulate the ovaries for medical reasons. Sometimes a semi-natural IVF, which means that you just take some pills that provoke ovulation can be used in women with a very poor ovarian reserve. As a general rule in IVF, you cannot get more eggs than the number of follicles that you see on the second day of the cycle on the initial ultrasound.
Let’s say that a woman has got a very poor ovarian reserve and has got only one or two follicles. In this case, there is no point in paying for medication because even if a woman takes a very high dose of medication and pays for all this medication, she will not be able to get more than one or two eggs. So in cases like that, natural cycle or repeated natural cycles makes sense. You can slowly start collecting one egg or two eggs at the time with double stimulation, so IVF that is taking place one after the other until the end you may get several eggs that you wouldn’t be able to get if you had more medication in one IVF.
Natural IVF does make sense. First, it reduces and makes the chances of hyperstimulation zero, but in specifically selected cases, it may even have a benefit. It is not though a common thing that we would do for any case. In general, the chances of success with natural IVF in comparison to a medicated IVF in a woman that has a lot of follicles are higher when we talk about medicated IVF.
Natural cycle IVF (NC-IVF) is a form of in vitro fertilization that involves little or no hormonal stimulation. Unlike traditional IVF, which uses medications to stimulate the ovaries to produce multiple eggs, natural cycle IVF relies on the woman’s natural menstrual cycle and the single egg that typically matures and is released each month. The process involves retrieving that naturally selected egg, fertilizing it in the lab, and then transferring the resulting embryo back into the uterus.
Success Rates of Natural Cycle IVF
The success rates of natural cycle IVF tend to be lower compared to conventional IVF. This is primarily because only one egg is retrieved during the process, and not all eggs are viable or successfully fertilized. With traditional IVF, multiple eggs are retrieved, increasing the chances of creating multiple embryos and selecting the healthiest one for transfer. With NC-IVF, the number of eggs, and thus the embryos, is limited to one, so if the egg quality is poor or fertilization fails, the cycle could be unsuccessful.
The success rate of natural cycle IVF also depends on factors such as the woman’s age, ovarian reserve, and overall fertility health. For women under 35, the success rate can range from 10% to 20% per cycle,
while for women over 40, the rate typically drops to less than 5% per cycle. In contrast, traditional IVF has a higher success rate, with averages of 25% to 40% per cycle for younger women.
Benefits of Natural Cycle IVF
Despite the lower success rates, natural cycle IVF offers several advantages that make it an attractive option for certain patients:
Who Might Benefit from Natural Cycle IVF?
NC-IVF might be suitable for specific groups of women, such as:
During this approach, we monitor the growth of the naturally chosen follicle, typically containing the healthiest egg, and may gently stimulate its development before retrieval.
For women in this age group, using excessive hormonal stimulation is often not effective, as their egg supply is usually limited, and many eggs may not be suitable for fertilization.
NC-IVF might allow the body to naturally select a higher-quality egg, although success rates in this age group are still lower.
By selecting the highest quality egg and minimizing drug use, the chances of successful fertilization improve, and the womb is provided with a more favourable environment for embryo implantation.
Limitations of Natural Cycle IVF
While NC-IVF has its benefits, it also has several limitations that must be considered:
Natural cycle IVF offers a less invasive, more affordable option for women seeking fertility treatment, particularly those with ethical concerns, low ovarian reserve, or sensitivity to medications. However, the lower success rates and the possibility of needing multiple cycles mean that it may not be the best choice for everyone. Women considering NC-IVF should carefully weigh the potential benefits and limitations and consult with their fertility specialist to determine if it’s the right approach for their unique situation.
Many patients worry about viral stimulation and try to avoid it, and they ask about natural cycle IVF. I always reply to these patients; that each procedure has its own indications, especially when we realize that the efficacy of a procedure is not optimal. We can use natural cycle IVF when a person has contraindications for ovarian stimulation; we have a special group of such patients. When the number of follicles that are in the ovaries is too small to provide ovarian stimulation, or we have advanced age patients or patients with premature ovarian failure or insufficiency, we can use natural cycle IVF. How does it work? We start ultrasound monitoring of the follicle growth and then the follicle reaches, comparing the ovulatory size, we prescribe trigger for oocyte maturation and then try to pick up this oocyte. And if our ovarian function was successful, and we retrieved mature oocytes, we can fertilize it or freeze it. This will depend on each situation. Why is this procedure not very effective? Follicles might not grow up during each cycle, they can ruptured sharply, oocytes can be immature, or they can be bad in quality so they might not be fertilized sometimes. And finally, embryos can develop differently and some of them can stop in development so we might not have any embryo transfer. So that’s why natural cycle IVF has much lower efficiency than conventional IVF
the attractive part for the patient is that all the hormones and their workings are quite natural -there are no additional hormones (maybe except for that one trigger shot, that trigger injection). Sometimes there’s a luteal support after the oocyte pickup. Also progesterone is applied but these are various modifications of the protocol. The downside of course is having just one egg so if that egg is not ripe, not healthy or the embryo doesn’t develop perfectly then, we need to repeat the cycle over and over and over again and it can be quite a lengthy and stressful process.
Natural cycle IVF is something very very common.
Let’s say that in recent years in our Center many women go for our natural IVF cycle and the reasons are many.
Scientifically the only real, the only true reason in order to do a natural IVF cycle is when a woman has already done a normal IVF so stimulation with really no result which means one to two oocytes.
In that case, of course, if stimulating the ovaries gives you only oocytes it’s not worth continuing this protocol so you shift to a natural cycle.
Another case but much less frequent is when the patient had a cancer in her life, a hormone dependent cancer or some autoimmune severe diseases which exclude an IVF stimulation. In these cases we also go for a natural cycle.
Of course it cannot have the same success rate of IVF protocol stimulation. We would say that it’s one-third of a normal IVF protocol. One woman should not do it only once, one woman who opts and wants to go for a natural cycle should do natural cycles every month in order to arrive at a good blastocyst and then try to transfer at least two or three blasters according to her age. Of course there is a good thing in a natural IVF which means that she doesn’t take any medication which means that nature selects the oocyte which means that she doesn’t spend so much money but she should be aware that there are many risks also in a natural cycle which means that we could lose the egg that somehow happens very often, the follicle could be empty or very often we take the oocyte and the oocyte cannot be fertilize.
This standard gives us low chances of success rates, low chances of being pregnant but it’s an option. I am repeating women who had an IVF protocol without any result or in some rare cases of cancer or autoimmune diseases.
Natural IVF is successful but is not that successful. In our opinion, that’s something that should be limited to very specific cases, and unfortunately, the majority of natural IVF is done in cases in which the results are very poor. The first risk is that the chances of not getting an egg after a natural IVF are very high. Some groups describe up to 50% of their collections in which they don’t get eggs, or the eggs are not of good quality. We’re just working with one egg, you can go through different cycles and try to collect 5 or 6 eggs in 5 or 6 months without using any hormones, but once more, I can’t see the point because the eggs are not going to be of better quality compared to those that you can get in stimulation, and you need to keep in mind that the time goes on. In cases in which you invest 6-8 months, especially when you are over 40, the quality of the eggs that you can get in your 6th or 7th cycle can be really worse than the ones that you get in your first attempt.
Therefore, in my opinion, the natural cycle is only useful in young girls who do not respond to a standard stimulation. Giving them drugs is going to be a waste of time and money because in these cases, especially patients under 37-38, the quality of the egg and the chances of getting that egg can be good. They have time to invest, to go through different rounds.
A lot of studies confirm that the number of eggs that you collected are directly related to the accumulated success rate of the cycle, and then patients, for example, that produce over 15 eggs have up to six times higher chances of having a baby than those that produce 3 eggs.
In my opinion, there is no contraindication to try to stimulate the patients and try to get as many eggs. The more eggs we get, the more embryos we’re going to have, the higher the chances of that patient ending up with a baby.
