Can IVF be started at other times of the menstrual cycle?

This review compared starting ovarian stimulation (OS) for egg collection at the conventional time early in the menstrual cycle, to starting it in the luteal phase, late in the cycle. It found that both timelines led to successful egg collection. Using two collections in one cycle may improve outcomes for patients with a poor response to OS.

The fertility treatment in vitro fertilization (IVF) begins with stimulating the ovaries to produce multiple follicles. In a natural menstrual cycle, the ovarian follicles develop and are selected early in the cycle. IVF has conventionally followed the same timeline, using OS medications at the beginning of the cycle.

However, it is also possible to stimulate the ovaries at other times of the menstrual cycle. The "Luteal" protocol begins stimulation late in the menstrual cycle. All embryos from luteal protocol IVF are frozen because the lining of the uterus is not receptive to embryos implanting after this protocol. It is even possible to use both conventional IVF and luteal IVF in one menstrual cycle, which is known as DuoStim IVF.

Luteal and DuoStim IVF have been used in recent years for patients who have a poor response to OS, meaning that few oocytes (eggs) are produced. Patients preserving fertility prior to cancer treatment, who need to complete egg collection quickly, have also used these alternate IVF treatments. It is not clear how Luteal and DuoStim IVF compare to Conventional IVF.

This review analyzed 15 studies comparing alternate IVF protocols to Conventional IVF.

Three studies of 2229 patients compared Luteal and Conventional IVF. They found that the two methods led to a similar number of collected oocytes. Additionally, four studies with 865 patients found that Luteal and Conventional IVF led to a similar number of oocytes for patients with a poor ovarian response (POR). Luteal IVF may slightly increase how long OS medications are needed.

Three studies looked at 808 patients undergoing egg freezing. They found that Luteal and Conventional IVF led to similar numbers of mature (MII) oocytes.

Four studies looked at DuoStim IVF for patients with POR. They found that patients retrieved 3.35 additional mature (MII) oocytes when using DuoStim. Significantly more patients with POR had at least one euploid (genetically normal) embryo when using DuoStim compared to Conventional protocol (33% vs. 19.3%).

This review found that Luteal IVF led to a similar number of oocytes as Conventional IVF. For patients with POR, DuoStim IVF led to more oocytes harvested. 

It is not clear how alternate IVF protocols influence birth rates. Also, the additional stimulation needed for Luteal and DuoStim protocols may impact treatment costs.