(Natural Cycle IVF)
The very first IVF treatments, the treatments that resulted in the world’s first test tube baby, Louise Brown, were natural cycle IVF treatments. The disadvantage that this procedure always resulted in the availability of just one egg cell was countered with the introduction of hormonal stimulation. The problem of relatively frequent premature ovulation was solved using GnRH analogues and later also antagonists.
However, it was only several decades later that the question was revisited as to whether natural cycle IVF (and, of course, ICSI) did not have some advantages after all alongside today’s conventional IVF.
NC-IVF is an extremely conservative process associated with hardly any drug-related effects.
Treatment in an unstimulated cycle does not involve the risk of ovarian hyperstimulation syndrome (OHSS). Multiple pregnancy is extremely rare, while NC-ICF is far less physically and emotionally stressful, as well as significantly less expensive.
However, it should not be neglected to mention that this procedure is also less effective and has less potential for success. The pregnancy rate per cycle is lower than with conventional IVF. This is due in the first instance to the fact that egg retrieval is not even possible in 10 – 15 % of patients due to premature ovulation. Another reason is that only one egg cell can be inseminated. However, because an average only 80 % of egg cells can be inseminated in IVF (whether NC or conventional), it stands to reason that the success rate must be lower.
In recent years there have been increasing numbers of scientific studies showing that the ability of the endometrium (the mucous lining of the uterus) to accommodate an implanted embryo appears to be lower in women undergoing conventional IVF than under normal conditions. This phenomenon is attributed to the extremely high oestrogen level that results from stimulation.
However, the almost complete absence of risks is an enormous advantage. Only the minor, uncomplicated egg retrieval procedure has at least a theoretical risk. The cycle overall is found to be significantly less stressful.
Neither GnRH antagonists nor GnRH agonists are necessary. The problem of premature ovulation can be solved effectively by administering certain medications either as tablets or suppositories. Only the somewhat more frequent required ultrasound and hormone tests involve a certain amount of extra burden on the patient and practice.
Egg retrieval can be performed without anaesthesia (or with a local anaesthetic if preferred). As a result, the woman can in principle return to work on the same day. Because the ovaries do not undergo the cystic enlargement that occurs with hormonal stimulation, there is no problem performing this treatment on several consecutive cycles. It should also be remembered that these cycles are considerably less expensive than cyclesthose that are with stimulationed, although the pregnancy rate after the embryo transfer (yes, just ONE embryo) is at 20 % per embryo transfer naturally lower than that achieved with “conventional IVF“, which involves the transfer of 2 – 3 embryos. However, you will see how little emotional and physical stress a cycle of this type will place on you.
Which women are eligible for natural cycle IVF/ICSI?
- Women who do not want hormone treatment
- Women who have had bad experiences with hormonal stimulation
- Women with a high risk of ovarian hyperstimulation syndrome (OHSS)
- So-called “low responders”, i.e. women who respond poorly to hormonal stimulation
- Older women, who often only produce 1 – 3 egg cells despite hormonal stimulation
- “Implantation failures”, i.e. women who have always had good embryos from conventional IVF but have never had the embryos implant.