Dual stimulation, also known by other names like the DuoStim or Shanghai protocol, and embryo banking, is a technique recommended when a good amount of embryos is needed, but the patient cannot produce that number in a single stimulation cycle. The idea is to stimulate the patient, retrieve the eggs, create embryos, freeze them, or conduct a biopsy in cases where Preimplantation Genetic Testing is needed. Then, as soon as the patient has her period, another round of IVF is initiated to obtain more eggs and create embryos. This process can be repeated as many times as needed, typically between 2 and 6 cycles, depending on each case and the number of blastocysts obtained in each cycle.
We know that follicles can grow up not only at the beginning of the cycle but actually this cohort of follicles can start to grow up at any day of the cycle. So this is the concept of follicular waves, so we have not only the first wave but we have the second and third day of growing follicles and when we started at the beginning of the cycle, we started to stimulate the first wave of follicles. They have grown up, maybe picked up these oocytes and after an ovarian puncture a few days later, we can start the stimulation again and we will pick up oocytes twice during one menstrual cycle.
The experience with the currently used DuoStim protocols which have been developed mainly for oncological patients at first. We’re actually following the oocyte pickup, three days later, another stimulation has started and the number of eggs, the quality of the eggs obtained through this second stimulation is, in most studies, even higher than during the first stimulation. We see that there are really or truly no restrictions that the ovaries are capable of great things but it’s unnecessary actually to push in most cases and to rush this fast. It’s also a question of the patient’s comfort with her psyche.
Double stimulation is a really good stimulation strategy if you are trying to accumulate as many eggs or embryos as possible. The classic patients that that’s really good for are fertility preservation patients who are either thinking about it in terms of social egg freezing or are about to embark on chemotherapy and they’ve got a really short window of time to have, as you know, as much stored as possible. The way that we can do that is that you can essentially use on the second day of your cycle, you start your gonadotropin injections, then add in the GnRH antagonist five days later and you continue those injections for a total of about 11 days. We do give you a final trigger injection. We do the egg retrieval 36 hours later and then five days later we’re starting again. Essentially it’s kind of straight into it and then you’re doing this exact same thing again: giving daily injections of gonadotropins and an antagonist and then a further egg retrieval and that’s another two weeks in total. Actually what that means is, you’re getting two ovarian stimulation cycles, with two egg retrieval, in a period of approximately four weeks and maximizing the egg yield for that which you can then store before you’re embarking on chemotherapy for example.
Dual or double stimulation in IVF is not very popular as most of our patients will have a problem with ovarian reserves as they leave maternity to a later time in life. When we have a patient with really low ovarian reserves, we must get as many oocytes as possible so we can have a bigger chance of a good quality one, which is the important one for the treatment. We need good quality eggs, for good quality embryos to get our patient pregnant. So double stimulation is basically a stimulation protocol through the first part of the menstrual cycle which is the follicular part and then in the second part of the cycle which is the oocyte retrieval, until the next period begins, we go for another protocol of IVF which is similar. But we take advantage of one cycle, between two protocols on each side of the whole menstrual period.
Double stimulation is a protocol where two stimulations are performed within the same cycle, starting the second simulation four days after performing the follicular puncture. This protocol is based on the follicular recruitment in the form of waves that occur during the ovarian cycle. The benefit is to make the most of the effect of the first stimulation on the development of new follicles. It is indicated in patients with low reserve and low response to stimulation.
