In fertility, time is vital to achieve pregnancy. Patients who come to an assisted reproduction center need a clear answer to their fertility problems. A high percentage of consultations are due to the maternal age factor.

We asked Dr. Marta Zermiani, gynaecologist and fertility specialist at Vida Fertility clinic in Madrid, who has given us a very interesting insight into what this protocol can do for patients with low ovarian activity.

Dual Stim is an ovarian stimulation protocol specially designed for patients with low ovarian response to hormonal stimulation. It is used in IVF (In Vitro Fertilisation) treatment and its main characteristic is that it involves two consecutive stimulations without having to wait for the menstrual cycle.

The first ovarian stimulation is performed in the conventional way, in the follicular phase, followed by a second stimulation in the luteal phase, normally 5 days after the first follicular puncture, and therefore without waiting for the start of the menstrual period.

Cryopreservation of the resulting embryos with delayed embryo transfer is necessary in all cases.

This protocol was initially used to preserve the fertility of oncology patients before starting chemotherapy treatments, in order to shorten the treatment and egg retrieval time. In this way they did not delay the start of cancer treatment.

It was later realised that patients with Poor Ovarian Responders (POR) due to low ovarian reserve could also benefit.

According to the definition provided by the ESHRE, following its meeting in Bologna in 2011, around 10.3% of women undergoing controlled ovarian stimulation would meet the criteria for POR.

Different ovarian stimulation regimens have been used to date in this subgroup of patients. With Dual Stim, the objective is to try to recover a greater number of oocytes per stimulated cycle, which is very interesting in these patients, especially if they are going to need Preimplantational Genetic Diagnosis (PGT-A) to select euploid embryos (those that are chromosomally normal).

The difference with traditional stimulation protocols lies mainly in the timing.

It is a classic follicular stimulation, which is normally carried out in the follicular phase (from the period until day 10-12 of the cycle) followed by another stimulation which is normally carried out between 2 and 5 days after the first puncture. At Vida Fertility we prefer to leave 5 days of rest between the puncture and the start of the second stimulation.

The second stimulation usually lasts 1-2 days longer than the first one and ends with another puncture 14-15 days after the start of the second stimulation.

The side effects are the same as in a classic ovarian stimulation:

Mood swings.

Abdominal discomfort.

Fluid retention.

Feeling of abdominal bloating.

During the second cycle the effects are usually more pronounced, although this is not always the case.

However, it should be remembered that this protocol is aimed at patients with low ovarian response, who do not usually have many symptoms during stimulations due to low ovarian activity.

There are several studies suggesting that Dual Stim can improve outcomes in patients with low ovarian reserve.

This protocol offers greater possibilities of oocyte recovery compared to conventional stimulation in the follicular phase in this profile of patients, without significant differences in the days of stimulation or cycle cancellation rates compared to classic stimulation.