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).

Patients will be stimulated according to the conventional flexible GnRH antagonist protocol for IVF. Alfa follitropin (150IU a day) will be started on the third day of the menstrual cycle. Treatment monitoring will be done with transvaginal ultrasound scans and serum determinations of estradiol and progesterone 5 days after the start of gonadotropins and every each day thereafter. Once the leading follicle reaches 13 mm in mean diameter 0,25mg of cetrorelix acetate will be administered daily. Once at least two follicles reach 18mm or more in mean diameter 250 micrograms of choriogonadotropin alfa will be administered and 36 hours latter patients will undergo follicle aspiration for IVF. Embryos will be cryopreserved (vitrification) on the third or fifth day of development. Two months after women will undergo uterine preparation for embryo transfer.

Patients will be monitored with daily transvaginal ultrasound scans from the tenth day of the menstrual cycle on. When the dominant follicle reaches a mean diameter of 16mm or more, patients will receive 250 micrograms of choriogonadotropin alfa subcutaneously. Daily transvaginal ultrasound scans will be done starting two days after the administration of the medication until a cohort of ovarian follicles between 4-6 mm is seen (follicular wave emergence). From this point on patients will undergo the same stimulation protocol as Controls, i.e., flexible GnRH antagonist protocol.

Patients will be monitored with daily transvaginal ultrasound scans from the tenth day of the menstrual cycle on. When the dominant follicle reaches a mean diameter of 16mm or more, patients will then undergo aspiration of the dominant and all follicles greater than 10mm in mean diameter. aspiration will be transvaginal ultrasound guided and under sedation, as for oocyte retrieval. Oocytes eventually obtained at this first aspiration will not be used for IVF. Daily transvaginal ultrasound scans will be done starting the day after the follicular aspiration until a cohort of follicles between 4-6 mm is seen (follicular wave emergence). From this point on patients will undergo the same stimulation protocol as Controls, i.e., flexible GnRH antagonist protocol.

Administration of 250 micrograms of choriogonadotropin alfa subcutaneously when the dominant follicle of a natural menstrual cycle reaches 16mm or more of mean diameter. Verify if this intervention is able to induce follicular wave emergence and synchronize the start of the flexible GnRH antagonist protocol of ovarian stimulation with the start of a follicular wave.

Aspiration of all follicles greater than 10mm in mean diameter when the dominant follicle of a natural menstrual cycle reaches 16mm or more of mean diameter. Aspiration will be guided by transvaginal ultrasound. Verify if this intervention is able to induce follicular wave emergence and synchronize the start of the flexible GnRH antagonist protocol of ovarian stimulation with the start of a follicular wave.

Conventional flexible GnRH antagonist protocol of ovarian stimulation for in vitro fertilization, with gonadotropin star at the third day of a natural menstrual cycle.

Evaluate if the aspiration of the dominant follicle is able to induce a follicular wave to emerge. Evaluate if administration of hCG is able to induce ovulation of a dominant follicle larger than 16mm and to induce a follicular wave to emerge. A follicular wave emergence is defined as an increase in the number of ovarian follicles smaller than 10mm seen at the transvaginal ultrasound scan after the interventions

Evaluate with periodic transvaginal ultrasound scan the size (mm), number and growth rate (mm/day) of ovarian follicles in each of the three groups

Evaluate blood levels of estradiol (pg/mL) and progesterone (ng/mL) during ovarian stimulation in each of the three groups at each visit to evaluate the progress of treatment.

Total dose of gonadotrophins (in international units) necessary to stimulate the ovaries (from the first day of stimulation until the last dose of recombinant FSH administered before the oocyte retrieval)

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)

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