Synchronization of Ovarian Stimulation for in Vitro Fertilization With Follicular Wave Emergence

The Role of Controlling Follicular Wave Emergence to Synchronize Ovarian Stimulation for in Vitro Fertilization

Ovarian stimulation is an important phase of in vitro fertilization (IVF) treatments. The harvest of a larger number of viable eggs per cycle compensate eventual laboratory difficulties and allow for the selection of embryos with higher implantation potential. In the current protocols, based on the most prevailing theory of ovarian follicular development, stimulation drugs are usually started on the second or third day after the beginning of menses. The follicular phase of the menstrual cycle is believed to be the only favorable moment for follicular development.

In the early 2000's a new model of human ovarian follicular development (follicular waves) has been proposed based on frequent transvaginal ultrasound observations between two ovulations. It has been shown that ovarian antral follicles develop in synchronous groups, two to three times in a cycle. In fact the follicular wave phenomenon has been initially described in the 80's on domestic animals, like the mare and the cow. Moreover, studies in these animals have shown that synchronizing the start of the ovarian stimulation drugs with the beginning of a follicular wave yields better results for assisted reproductive treatments. Consequently in ovarian stimulation protocols for animal assisted reproduction it is important to control the initiation of a follicular wave.

Current protocols of ovarian stimulation for IVF in women do not consider the start of a follicular wave to begin drug administration. Therefore the purpose of this study is to evaluate two methods to control the emergence of a follicular wave (ovulation induction and dominant follicle aspiration) and to investigate the effects of synchronizing ovarian stimulation for IVF with follicular wave emergence in women compared to one of the current stimulation protocols (flexible GnRH protocol).

Inclusion Criteria:

• age < 35 years old
• body mass index: 19-30 kg/m2
• tubal or male factor infertility with indication of in vitro fertilization
• antral follicle count: 10-20
• normal uterus in transvaginal ultrasound scan
• FSH on the third day of the menstrual cycle below 12mUI/mL and estradiol below 80pg/mL
• male partner with at least 5 million motile sperm and 1% normal strict morphology on semen analyses

Exclusion Criteria:

• ovarian factor infertility
• non identification of one or both ovaries in the transvaginal ultrasound scan
• non treated endocrine disorders
• smoking habit
• endometriosis stage III -IV
• severe male factor infertility (less than one million sperm per mL of semen)