5 days of Cetrotide before trigger
Cetrotide (cetrorelix) is typically administered for 5 consecutive days before the trigger shot in IVF cycles. This GnRH antagonist prevents premature ovulation by blocking LH and FSH release. The 5-day protocol begins on cycle day 5 or 6 of stimulation and continues until the trigger day.
Cetrotide administration schedule
- Day 1-5: 0.25 mg subcutaneous injection daily
- Continue until trigger shot administration
- Trigger typically given when lead follicles reach 17-20mm
Comparison of antagonist protocols
| Protocol | Cetrotide Duration | Trigger Type | Typical Start Day |
|---|---|---|---|
| Standard | 5 days | hCG or dual | Day 5-6 of stimulation |
| Late Antagonist | 3 days | hCG | Day 7-8 of stimulation |
| Prolonged | 7+ days | hCG or agonist | Day 3-4 of stimulation |
Factors affecting Cetrotide duration
- Patient response to stimulation medications
- Ovarian reserve and age
- Previous cycle outcomes
- Physician protocol preference
Important considerations
Missing a Cetrotide dose can increase risk of premature LH surge. If a dose is missed, contact your fertility clinic immediately. The 5-day standard protocol balances prevention of premature ovulation with minimizing medication exposure.