Is oocyte maturation rate associated with triptorelin dose used for triggering final oocyte maturation in patients at high risk for severe ovarian hyperstimulation syndrome?

Study Question: Are oocyte maturation rates different among 0.1, 0.2 and 0.4 mg triptorelin used for triggering final oocyte maturation in patients at high risk for ovarian hyperstimulation syndrome (OHSS) undergoing ICSI?

Summary Answer: A dose of 0.1 mg triptorelin results in similar oocyte maturation rates compared to higher doses of 0.2 and 0.4 mg in patients at high risk for OHSS undergoing ICSI.

What Is Known Already: The GnRH agonist triptorelin is widely used instead of hCG for triggering final oocyte maturation, in order to eliminate the risk of severe OHSS in patients undergoing ovarian stimulation for IVF/ICSI. However, limited data are currently available regarding its optimal dose use for this purpose in patients at high risk for OHSS.

Study Design, Size, Duration: A retrospective study was performed between November 2015 and July 2017 in 131 infertile patients at high risk for severe OHSS undergoing ovarian stimulation for ICSI. High risk for severe OHSS was defined as the presence of at least 19 follicles ≥11 mm in diameter on the day of triggering final oocyte maturation.

Participants/materials, Setting, Methods: Ovarian stimulation was performed with recombinant FSH and GnRH antagonists. Patients received 0.1 (n = 42), 0.2 (n = 46) or 0.4 mg (n = 43) triptorelin for triggering final oocyte maturation. Hormonal evaluation of FSH, LH, estradiol (E2) and progesterone (PRG) was carried out on the day of triggering final oocyte maturation, 8 and 36 hours post triggering and 3, 5, 7, and 10 days after triptorelin administration. During this period, all patients were assessed for symptoms and signs indicative of severe OHSS development. Primary outcome measure was oocyte maturation rate, defined as the number of metaphase II (MII) oocytes divided by the number of cumulus-oocyte-complexes retrieved per patient. Results are expressed as median (interquartile range).

Main Results And The Role Of Chance: No significant differences in patient baseline characteristics were observed among the 0.1 mg, the 0.2 mg and the 0.4 mg groups. Regarding the primary outcome measure, no differences were observed in oocyte maturation rate among the three groups compared [82.6% (17.8%) versus 83.3% (18.8%) versus 85.1% (17.2%), respectively, P = 0.686].In addition, no significant differences were present among the 0.1 mg, 0.2 mg and 0.4 mg groups, regarding the number of mature (MII) oocytes [21 (13) versus 20 (6) versus 20 (11), respectively; P = 0.582], the number of oocytes retrieved [25.5 (13) versus 24.5 (11) versus 23 (12), respectively; P = 0.452], oocyte retrieval rate [81.0% (17.7%) versus 76.5% (23.5%) versus 75.0% (22.5), respectively; P = 0.088], the number of fertilized (two pronuclei) oocytes [12.5 (9) versus 14.5 (7) versus 14.0 (8), respectively; P = 0.985], fertilization rate [71.7% (22%) versus 77.1% (19.1%) versus 76.6% (23.3%), respectively; P = 0.525] and duration of luteal phase [7 (1) versus 8 (2) versus 7 (1) days, respectively; P = 0.632]. Moreover, no significant differences were present among the three triptorelin groups regarding serum levels of LH, FSH, E2 and PRG at any of the time points assessed following triggering of final oocyte maturation.

Limitations, Reasons For Caution: This is a retrospective study, and although there were no differences in the baseline characteristics of the three groups compared, the presence of bias cannot be excluded.

Wider Implications Of The Findings: Based on the results of the current study, it appears that triggering final oocyte maturation with a lower (0.1 mg) or a higher dose (0.4 mg) of triptorelin, as compared to the most commonly used dose of 0.2 mg, does not confer any benefit in terms of oocyte maturation rate in patients at high risk for severe OHSS.

Study Funding/competing Interest(s): No external funding was obtained for this study. There are no conflicts of interest.