A Phase 4 interventional study of Gonal-F® and Cetrotide® in Infertility, sponsored by Assistance Publique - Hôpitaux de Paris. Completed at 1 site in France. Open to female participants aged 18 Years to 40 Years. Per ClinicalTrials.gov, last updated 2026-04-03.
Sponsored by Assistance Publique - Hôpitaux de Paris · Phase 4, Interventional, and Treatment
To overcome unsuitable effects of controlled ovarian hyperstimulation (COH )while maintaining large oocyte availability, investigators elaborated an innovative protocol (NATural Ovarian Stimulation) that dissociates E2 production from multiple follicle development.
The purpose of this prospective, randomized trial is to demonstrate that, in a good prognosis IVF-ET population, the physiological E2 environment resulting from NATOS significantly improves IVF-ET outcome when compared to the conventional GnRH antagonist protocol.
Controlled ovarian hyperstimulation (COH) seeks to improve IVF-ET results by increasing per-cycle oocyte and embryo availability. Yet, the coexistence of multiple preovulatory follicles engenders compulsory alterations in the endocrine milieu of the follicular phase. The most evident of them are the extremely high serum estradiol (E2) levels. The 10 to 15-fold increase in E2 levels as a result of COH has been shown to provoke unwanted consequences in both embryo quality and uterine receptivity.
Therefore, investigators elaborated an innovative COH protocol (NATural Ovarian Stimulation) that aimed at dissociating E2 production from multiple follicle development. To obtain this effect, they virtually curtailed endogenous LH production by using GnRH antagonist doses as strong and frequent enough to maintain E2 levels around the physiological range during standard exogenous FSH-only administration. Given that high E2 levels are commonly reached in patients having a normal follicle endowment, NATOS should target this group of good prognosis IVF-ET candidates. Indeed, this new COH approach was first tested in a pilot study that included 15 good prognosis IVF-ET candidates, aged 25-35 years, who volunteered to undergo NATOS. 11 out of 15 patients achieved a pregnancy. These pilot results spurred them to conduct a prospective, randomized trial to demonstrate that, in a good prognosis IVF-ET population, the physiological E2 environment resulting from NATOS significantly improves IVF-ET outcome when compared to the conventional GnRH antagonist protocol.
2,506 studies on the registry are indexed under Infertility; 407 are open to participants now.
This study's enrollment of 129 is close to the median of 120 across 1,698 interventional studies indexed under Infertility.
Browse Infertility studies →Assistance Publique - Hôpitaux de Paris is the lead sponsor of 3,505 studies on the registry; 1,006 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Background therapy which is the usual COH treatment: * Recombinant FSH (Gonal-F®, 225 to 450 IU/d; MerckSerono Pharmaceuticals) from day 2 of their menstrual cycle onward, * GnRH antagonist (Cetrotide®, MerckSerono Pharmaceuticals) 0.25 mg/day, S.C., starting on day 6 of Gonal-F®.
Drug: Gonal-F® · Drug: Cetrotide®
Background therapy which is the usual COH treatment: * Recombinant FSH (Gonal-F®, 225 to 450 IU/d; MerckSerono Pharmaceuticals) from day 2 of their menstrual cycle onward, * GnRH antagonist (Cetrotide®, MerckSerono Pharmaceuticals) 0.25 mg/day, S.C., starting on day 6 of Gonal-F®. GnRH antagonist treatment (Cetrotide®, MerckSerono Pharmaceuticals) will be reinforced and patients will receive 1.5 mg/day (6 ampoules of 0.25 mg), S.C., starting on day 1 (S1) of Gonal-F® treatment until dhCG
Drug: Gonal-F® · Drug: Cetrotide®
225 to 450 IU/d; from day 2 of menstrual cycle onward
0.25 mg/day, starting on day 6 of Gonal-F®.
1.5 mg/day (6 ampoules of 0.25 mg), starting on day 1 (S1) of Gonal-F® treatment until dhCG
Live birth obtained after IVF-ET
Live birth defined as delivery ≥ 22 weeks of amenorrhea
Time frame: 1 month post-partum
Number of oocytes obtained
Time frame: At oocyte retrieval (14±8 days after start of treatment)
Number of embryos obtained
Time frame: At day 2 of embryo development
Clinical pregnancy
Clinical pregnancy defined as pregnancy with an US-detectable gestational sac at 7 weeks of amenorrhea
Time frame: 7 weeks of amenorrhea
Embryo implantation
Embryo implantation defined as the total number of intrauterine gestational sacs divided by the total number of embryos transferred
Time frame: 7 weeks of amenorrhea
Miscarriage
Miscarriage defined as a pregnancy loss between 7 and 13 weeks of amenorrhea
Time frame: Between 7 and 13 weeks of amenorrhea
"Top" quality embryo
Embryo data assessed by the number of embryos with adequate morphology
Time frame: 4 and 5 days after hCG administration
Blastulation
Number of cleaving embryos having reached the blastocyst stage
Time frame: 7 days after hCG administration
Adverse events occurring during COH
Presence of ovarian hyperstimulation syndrome (OHSS) +/- severity is measured using OHSS evaluation scale
Time frame: Within the first 30 days after the start of treatment;
Gestational age at delivery
Time frame: 1 month post-partum
Birth weight
Time frame: 1 month post-partum
Pregnancy complications
antepartum haemorrhage, placental abruption, hypertensive disorders, and perinatal mortality
Time frame: 1 month post-partum
Patient's quality of life during COH
Fertiqol modified
Time frame: At 14 days from start of treatment with cetrotide (plus or minus 8 days)
Reduced serum E2 levels on dhCG (< 800 pg/mL)
serum E2 levels will be measured from each blood sample obtained during COH
Time frame: the day of hCG administration
Serum androgens levels during COH
Serum androgens levels (testosterone, SHBG, androstenedione)
Time frame: Within the first 19 days after start of treatment with cetrotide (plus or minus 8 days)
Plan to share: No
No publications or documents are linked to this record.
This study is completed, as verified in Mar 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Assistance Publique - Hôpitaux de Paris