What are the advantages of the DuoStim strategy?

In recent years, folliculogenesis in women has been shown to occur in a wave-like pattern, with two or three waves of follicular development during one menstrual cycle. Moreover, it has been shown that follicles formed beyond the follicular phase have similar ovulation potential, opening new windows for assisted reproductive treatment (ART). Thus, the double stimulation strategy has been proposed as an attractive alternative to obtain a higher number of eggs and embryos in a shorter period of time, which would theoretically increase the cumulative live birth rate and reduce the time to pregnancy. In this protocol, controlled ovarian stimulation (COS) is performed twice in the same menstrual cycle, taking advantage of both the follicular and the luteal phase. The results obtained so far indicate that luteal phase stimulation is not inferior to follicular phase stimulation. Additionally, the double stimulation protocol has proved to be as safe as conventional COS, while improving reproductive outcomes when compared to single follicular phase stimulation. In this context, it also emerges as an interesting option for emergency fertility preservation in oncologic patients. However, the absence of randomized controlled trials and cost-effective analysis raises important concerns that need to be addressed in depth via well-designed studies.