In the field of assisted reproduction, technological and clinical advances have transformed the chances of success in complex cases. One of the most significant approaches of the last decade is the Shanghai Protocol, also known as DuoStim, which has marked a turning point in ovarian stimulation. In this article, we explore what makes it so effective, what the evidence says after 10 years of application, and how we successfully implement it at Clínica Fertia.
What is the DuoStim Protocol and why has it revolutionised fertility?
The DuoStim Protocol, also known as the Shanghai Protocol, represents an innovation in ovarian stimulation for in vitro fertilisation (IVF) treatments. Unlike traditional methods, this technique performs double ovarian stimulation in the same menstrual cycle — one in the follicular phase and one in the luteal phase — which increases the number of mature oocytes available. At Clínica Fertia, we have been successfully applying this strategy for more than 8 years in patients with low ovarian reserve, advanced maternal age and women who require urgent fertility preservation due to a cancer diagnosis.
What have we learned 10 years after its implementation?
A scientific review published in 2025 has summarised the findings of all studies conducted to date. These are the main points that have been confirmed:
- It increases the total number of mature oocytes per cycle, especially in women with low ovarian response.
- It significantly reduces treatment time, saving up to 2.5 months compared to conventional protocols.
- It improves the efficiency of fertility preservation in cancer patients, without the need to wait for the start of the menstrual cycle.
However, there are still some unanswered questions:
- There is no conclusive evidence that it increases the live birth rate.
- The long-term safety of cryopreserved oocytes, especially in cancer patients, is still under investigation.
Physiological basis: why does it work?
The Shanghai Protocol is based on the theory of multiple follicular waves, which demonstrated that the ovaries generate several waves of follicles in each cycle. Taking advantage of both the follicular and luteal phases allows more oocytes to be recruited without compromising their quality. In addition, the high concentration of progesterone in the luteal phase prevents spontaneous ovulation, allowing for more controlled and effective stimulation.
What does the 2025 scientific review contribute?
Rather than presenting a new approach, the review article published in 2025 contributes:
- A compilation of the most relevant clinical trials conducted over the last decade.
- A critical analysis of the variability in doses and protocols between centres.
- A call for standardisation of the technique and its democratisation in countries with fewer resources.
- An ethical reflection on the cost-benefit ratio in vulnerable patients.
Who benefits from the DuoStim Protocol (double ovarian stimulation)?
This approach has proven to be particularly effective in:
- Patients with low ovarian reserve (POR): it increases the number of available oocytes and improves treatment efficiency.
- Cancer patients: it allows stimulation to begin immediately, without waiting for the start of the menstrual cycle, which is vital before starting gonadotoxic therapies.
- People who need preimplantation genetic testing (PGT-A): by obtaining more embryos in a single cycle, the time to obtain a euploid blastocyst is reduced.
Limitations and future challenges
Although the advantages of the Shanghai Protocol, also known as DuoStim, are clear, challenges remain:
- Lack of standardisation between clinical centres.
- High economic cost compared to single cycles.
- Need for more long-term studies on neonatal safety and live birth rates.
At Clínica Fertia, we work with personalised protocols and continuous monitoring to reduce risks such as ovarian hyperstimulation, which is exceptionally low in this protocol (<1%).
Are we looking at the new standard?
After a decade of use, the DuoStim Protocol (double ovarian stimulation) is no longer experimental, but has become a solid and effective option in personalised assisted reproduction. Its ability to optimise results in complex cycles and reduce waiting times is especially valuable for those who cannot afford to lose even a month on their journey to motherhood.
At Clínica Fertia, we will continue to focus on the most advanced techniques, always with a scientific, ethical and human approach.
