Evaluation of Time Interval Between Ovulation Trigger With Triptorelin Acetate and Oocyte Retrieval

Human chorionic gonadotrophin (hCG) has been the gold standard for ovulation induction for several decades. When GnRH antagonist protocols were introduced, it became possible to trigger final oocyte maturation and ovulation with a single bolus of a GnRH agonist (GnRHa) as an alternative to hCG. The use of GnRHa to trigger final oocyte maturation has potential advantages: the simultaneous induction of a FSH surge, higher numbers of mature oocytes retrieved as compared to hCG and the total elimination of ovarian hyperstimulation syndrome.

From the earliest reports of GnRHa for ovulation triggering, it has been presumed that the timing of the ovum pick-up (OPU) after GnRHa administration should be the same as after hCG triggering (34-36 h). However, differences exist regarding the duration and profile of the GnRHa induced surge of gonadotrophins when compared with that of hCG. Even more, differences in the intra-follicular mechanisms involved in ovulation have been described after GnRHa and hCG trigger.

No previous randomized controlled trials have been reported to evaluate the optimal interval of time between ovulation induction by GnRHa and oocyte collection.

The present study compares the ovarian response and the IVF outcomes after induction by triptorelin 0.2 mg at four different time intervals:

Group 1: OPU 24 hours after GnRHa administration. Group 2: OPU 30 hours after GnRHa administration. Group 3: OPU 40 hours after GnRHa administration. Group 4: control group: OPU 36 hours after GnRHa administration.

Inclusion criteria

• Signed informed consent prior to carry out any procedure associated with the clinical trial.
• Women between 18 and 37 years of age at the time of randomization (both ages included).

Basal serum levels of FSH <10 mIU /ml.

• Serum AMH > 5 to <45 pmol / l.
• Antral follicle count > 6 and < 24.
• Vaginal ultrasound documenting correct visualization of both ovaries and the absence of significant ovarian pathology.
• Short stimulation protocol with GnRH antagonist and conventional dose for ovarian stimulation with 225-300 UI of rhFSH.
• Number of follicles ≥ 16 mm > 5 on the ovulation induction day.

Exclusion criteria

• Presence of severe endometriosis (Grade III-IV).
• Absence of one ovary due to previous surgery.
• Presence of significant uterine pathology (submucous myomas, endometrial polyp, malformations..)
• Diagnosis of polycystic ovary syndrome (defined according to the Rotterdam criteria).
• History of previous poor response to conventional ovarian stimulation protocols (< 3 MII oocytes or canceled cycle)
• Severe male factor ( TMS< 1 million).
• Participation in another RCT within the past one year.