title: GnRHa trigger and individualized luteal phase hCG support according to ovarian response to stimulation: two prospective randomized controlled multi-centre studies in IVF patients.
abstract: OBJECTIVE
  Does a GnRH agonist (GnRHa) trigger followed by a bolus of 1.500 IU hCG in a group of patients at risk of ovarian hyperstimulation syndrome (OHSS) reduce the OHSS incidence compared with hCG trigger?
  
  
  CONCLUSIONS
  A GnRHa trigger followed by early luteal hCG support with one bolus of 1.500 IU hCG appears to reduce OHSS in patients at risk of OHSS; however, in a low-risk group a second bolus of 1.500 IU hCG induced two cases of late onset OHSS.
  
  
  BACKGROUND
  A GnRHa trigger is an alternative to hCG in GnRH antagonist co-treated cycles.
  
  
  METHODS
  Two RCTs were performed in four Danish IVF units. A total of 446 patients were assessed for eligibility and 390 patients were enrolled in the study from January 2009 until December 2011. The primary outcome of the study was OHSS incidence in the group at risk of OHSS.
  
  
  METHODS
  Patients received a fixed dose of recombinant human FSH for the first 4 days. On the day of triggering, patients were assessed for their risk of OHSS based on the total number of follicles ≥11 mm diameter, and were classified as being at risk of OHSS when the total number of follicles ≥11 mm was between 15 and 25 and at low risk of OHSS when the total number of follicles ≥11 mm was ≤14. Two separate randomization lists were used for each of the OHSS risk groups. Women at risk of OHSS were allocated (RCT 1) to either: Group A (n = 60), ovulation triggering with a bolus of 0.5 mg buserelin (GnRHa) s.c. followed by a single bolus of 1.500 IU hCG s.c. after the oocyte retrieval-or: Group B (n = 58): 5.000 IU hCG. Similarly, women at low risk of OHSS were allocated (RCT 2) to receive either: Group C (n = 125), a bolus of 0.5 mg buserelin s.c., followed by a bolus of 1.500 IU hCG s.c. after oocyte retrieval and a second bolus of 1.500 IU hCG on the day of oocyte retrieval +5-or: Group D (n = 141), 5.000 IU hCG. Groups C and D were included in order to obtain preliminary data.
  
  
  RESULTS
  In women at risk of OHSS (RCT 1) (15-25 follicles) no OHSS case was seen in Group A (GnRHa trigger and one bolus of 1.500 IU hCG), whereas two cases of moderate late-onset OHSS occurred in group B (3.4%), (P = 0.24). In contrast, in women at a low risk of OHSS (RCT 2) (≤14 follicles) two cases of late-onset OHSS occurred in Group C (GnRHa trigger and two boluses of 1.500 IU hCG), whereas no OHSS case was encountered in Group D (P = 0.22).
  
  
  CONCLUSIONS
  Although the first RCT was powered to include 168 patients at risk of OHSS (15-25 follicles ≥11 mm) randomized to either GnRHa trigger or hCG trigger, the trial was prematurely discontinued when a total of 118 patients at risk of OHSS were randomized. In addition the second RCT in the OHSS low-risk group was designed as a feasibility study to assess the incidence of OHSS after GnRHa trigger and dual hCG administration versus 5.000 IU hCG. No power calculation was performed for this trial. In addition, there was a lack of blinding in the RCTs.
  
  
  CONCLUSIONS
  Although a non-significant result, one bolus of 1.500 IU hCG after GnRHa trigger tended to reduce the OHSS rate in patients with 15-25 follicles ≥11 mm as well as secure the ongoing pregnancy rate. In contrast, in patients at low risk of OHSS the administration of two boluses of 1.500 IU hCG after GnRHa trigger should be avoided as it may induce OHSS.
authors.affiliation: The Fertility Clinic, Skive Regional Hospital, Skive, Denmark. peter.s.humaidan@gmail.com
authors.forename: P
authors.initials: P
authors.lastname: Humaidan
authors.forename: N P
authors.initials: NP
authors.lastname: Polyzos
authors.forename: B
authors.initials: B
authors.lastname: Alsbjerg
authors.forename: K
authors.initials: K
authors.lastname: Erb
authors.forename: A L
authors.initials: AL
authors.lastname: Mikkelsen
authors.forename: H O
authors.initials: HO
authors.lastname: Elbaek
authors.forename: E G
authors.initials: EG
authors.lastname: Papanikolaou
authors.forename: C Y
authors.initials: CY
authors.lastname: Andersen
mesh_terms: D000328:Adult; D006063:Chorionic Gonadotropin / Q000008:administration & dosage* / Q000009:adverse effects / Q000494:pharmacology; D003338:Corpus Luteum / Q000000981:diagnostic imaging / Q000187:drug effects*; D003718:Denmark / Q000453:epidemiology; D004305:Dose-Response Relationship, Drug; D057239:Early Termination of Clinical Trials; D005240:Feasibility Studies; D005260:Female; D005300:Fertility Agents, Female / Q000009:adverse effects / Q000494:pharmacology*; D005307:Fertilization in Vitro / Q000009:adverse effects; D043373:Follicle Stimulating Hormone, Human / Q000494:pharmacology; D007987:Gonadotropin-Releasing Hormone / Q000819:agonists* / Q000037:antagonists & inhibitors; D006801:Humans; D015994:Incidence; D007247:Infertility, Female / Q000000981:diagnostic imaging / Q000628:therapy; D016471:Ovarian Hyperstimulation Syndrome / Q000453:epidemiology / Q000517:prevention & control*; D010053:Ovary / Q000000981:diagnostic imaging / Q000187:drug effects; D010062:Ovulation Induction / Q000009:adverse effects*; D057285:Precision Medicine; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology; D012306:Risk; D012720:Severity of Illness Index; D014463:Ultrasonography
chemical_list: D006063:Chorionic Gonadotropin; D005300:Fertility Agents, Female; D043373:Follicle Stimulating Hormone, Human; D011994:Recombinant Proteins; D007987:Gonadotropin-Releasing Hormone
keywords: GnRH agonist trigger; GnRH antagonist; IVF; hCG; ovarian hyperstimulation syndrome