Our science for you

A 2013 study published in the journal "Reproductive Biology and Endocrinology" describes the egg retrieval technique used in IVF-Naturelle® treatment. We were able to demonstrate that follicle flushing increases egg yield and that three flushing steps are necessary to achieve maximum egg yield. Therefore, IVF-Naturelle® centers frequently perform additional follicle flushing during follicular aspiration.

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In a 2014 study published in the "Journal of Reproductive Medicine", we compared the number of visits required for natural cycle IVF and for conventional IVF treatment, as well as their costs and time expenditure per pregnancy achieved.

According to this study, the cost (for the center) per pregnancy achieved with natural cycle IVF is 15% lower than with conventional IVF treatment. This is, of course, only true if the IVF therapy is carried out with the minimum number of visits described for Bern and the pregnancy rates achieved there. However, the time required to achieve a pregnancy is 30% longer. The study also shows that 69% of patients find egg retrieval less unpleasant with natural cycle IVF than with conventional IVF, even though no anesthesia or pain medication is administered during IVF-Naturelle®.

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A 2014 study published in the journal "Reproductive Biomedicine Online" compared one of our IVF-Naturelle® therapies with a low dose of clomiphene citrate to natural cycle IVF without clomiphene citrate, examining their success parameters. According to this study, we were able to demonstrate that our clomiphene citrate therapy, despite requiring only 1.1 visits before follicle aspiration (follicle monitoring), resulted in a significantly lower risk of premature ovulation and thus a considerably higher probability of embryo transfer and pregnancy per treatment cycle. The medications used were almost entirely free of side effects.

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A 2014 study published in the journal "Human Reproduction" shows that the composition of a follicle developed under gonadotropin stimulation, as in conventional IVF treatment, contains significantly lower concentrations of proteins relevant to pregnancy prognosis than a follicle that matures without any hormonal stimulation. In particular, it was striking that anti-Müllerian hormone (AMH), considered a marker for a high probability of pregnancy, is approximately three times more concentrated in a naturally mature follicle than in a follicle developed under high-dose gonadotropin stimulation.

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A 2017 study published in the journal "Acta Obstetrica Gynaecologica Scandinavica" showed that the psychological burden on women undergoing three IVF-Naturelle® cycles was lower than with conventional IVF treatment using high-dose hormone stimulation. Both treatment-related stress markers and depression markers improved during the IVF-Naturelle® treatment.

A 2017 study published in the journal "Reproductive Biomedicine Online" showed that daily progesterone administration after egg retrieval is not necessary in most cases of natural cycle IVF. This makes the treatment even more comfortable.

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A 2023 study published in the journal "Reproductive Biomedicine Online" showed that embryo quality is better with natural cycle IVF than with conventional, fully stimulated IVF. This is likely the reason for the 1.4-fold higher live birth rate we demonstrated in 2023 when transferring embryos generated in a natural cycle rather than with conventional IVF (Mitter … von Wolff, Reprod Sci, 2023). 

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A 2025 study involving eight IVF-Naturelle® centers in Switzerland and Germany, published in the journal "Reproductive Biomedicine Online," demonstrated, based on several thousand cycles, that follicle aspiration without anesthesia is associated with only mild pain. This also applies to the aspiration of multiple or repeated cycles. The risk of complications was less than 0.001%. 

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A study with 8 IVF-Naturelle® centers in Switzerland and Germany from 2025, published in the journal "Journal of Assisted Reproduction and Genetics", showed, based on several thousand cycles, that oocytes from natural IVF have the best, oocytes from minimally stimulated IVF the second best, and oocytes from classic IVF the worst development potential.

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In another study, submitted for publication in 2026, we used several thousand IVF cycles to determine which stimulation regimen is best suited for freezing eggs for social freezing or after cancer therapy in cases of reduced ovarian reserve. The study showed that minimal stimulation offers the best compromise between effort and cost when ovarian reserve is low.