---
title: Fixed Versus Flexible Gonadotropin-releasing Hormone (GnRH) Antagonist Initiation
nct_id: NCT01005784
overall_status: COMPLETED
phase: PHASE4
sponsor: Aristotle University Of Thessaloniki
study_type: INTERVENTIONAL
primary_condition: Subfertility
countries: Greece
canonical_url: "https://parkinsonspathways.com/agent/trials/NCT01005784.md"
clinicaltrials_gov: "https://clinicaltrials.gov/study/NCT01005784"
ct_last_update_post_date: 2009-11-02
last_seen_at: "2026-05-12T06:42:00.484Z"
source: ClinicalTrials.gov (mirrored, no enrichment)
---
# Fixed Versus Flexible Gonadotropin-releasing Hormone (GnRH) Antagonist Initiation

**Official Title:** Fixed Versus Flexible GnRH Antagonist Initiation

**NCT ID:** [NCT01005784](https://clinicaltrials.gov/study/NCT01005784)

## Key Facts

- **Status:** COMPLETED
- **Phase:** PHASE4
- **Study Type:** INTERVENTIONAL
- **Target Enrollment:** 146
- **Lead Sponsor:** Aristotle University Of Thessaloniki
- **Conditions:** Subfertility
- **Start Date:** 2005-06
- **Completion Date:** 2008-03
- **CT.gov Last Update:** 2009-11-02

## Brief Summary

This is a comparison of pregnancy achievement between two GnRH antagonist protocols which differ in the timing of GnRH antagonist initiation.

## Eligibility

- **Minimum age:** 18 Years
- **Maximum age:** 39 Years
- **Sex:** FEMALE
- **Healthy Volunteers:** No

```
Inclusion Criteria:

* \< 39 years of age
* BMI 18.5-29.9
* \<= 3 previous IVF cycles

Exclusion Criteria:

* PCOS
* Endometriosis
```

## Arms

- **fixed** (ACTIVE_COMPARATOR)
- **flexible** (EXPERIMENTAL)

## Interventions

- **Cetrorelix (Cetrotide)** (DRUG) — flexible antagonist administration according to specified criteria
- **Cetrorelix (Cetrotide)** (DRUG) — fixed antagonist administration on day 6 of ovarian stimulation

## Primary Outcomes

- **Luteinizing hormone rise** _(time frame: 3-14 days (duration of ovarian stimulation))_

## Locations (1)

- Unit for Human Reproduction, Thessaloniki, Greece

## Recent Field Changes (last 30 days)

- `status.overallStatus` — added _(2026-05-12)_
- `status.primaryCompletionDate` — added _(2026-05-12)_
- `status.completionDate` — added _(2026-05-12)_
- `status.lastUpdatePostDate` — added _(2026-05-12)_
- `design.phases` — added _(2026-05-12)_
- `design.enrollmentCount` — added _(2026-05-12)_
- `eligibility.criteria` — added _(2026-05-12)_
- `eligibility.minAge` — added _(2026-05-12)_
- `eligibility.maxAge` — added _(2026-05-12)_
- `eligibility.sex` — added _(2026-05-12)_
- `outcomes.primary` — added _(2026-05-12)_
- `armsInterventions.arms` — added _(2026-05-12)_
- `armsInterventions.interventions` — added _(2026-05-12)_
- `sponsor.lead` — added _(2026-05-12)_
- `results.hasResults` — added _(2026-05-12)_
- `locations.unit for human reproduction|thessaloniki||greece` — added _(2026-05-12)_

---

*Canonical: https://parkinsonspathways.com/agent/trials/NCT01005784.md*  
*Source data (authoritative): https://clinicaltrials.gov/study/NCT01005784*  
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