Ovarian stimulation protocols
How each protocol used in IVF/ICSI works, with indications, medication and safety.
- GnRH antagonist protocolShort antagonist protocol — current first-line in modern ART.Duration: 10–14 days
- Long agonist protocolClassic protocol with extended pituitary suppression.Duration: 21–35 days
- Short flare agonist protocolLeverages the initial endogenous FSH flare from agonist administration.Duration: 10–14 days
- Mini-IVF (minimal stimulation)Mild stimulation with clomiphene or letrozole plus low-dose gonadotropins.Duration: 10–12 days
- Natural cycle IVFNo stimulation or antagonist-only to prevent premature LH surge.Duration: 12–14 days
- DuoStim (double stimulation)Two stimulations within the same menstrual cycle (follicular + luteal).Duration: 25–32 days
- Endometrial preparation for frozen embryo transfer (FET)Estrogen + progesterone to build the implantation window.Duration: 14–21 days
Ovarian-stimulation protocols used for IVF/ICSI in Portugal
Choice of stimulation protocol is one of the most consequential clinical decisions in an IVF cycle. CNPMA-licensed Portuguese centres use four protocol families in 2024: **antagonist** (GnRH antagonist, the standard), **long agonist** (GnRH agonist, still indicated in selected cases), **mini-IVF** (low-dose gonadotrophin in low ovarian reserve) and **natural / modified natural** (no or minimal stimulation). The choice depends on age, ovarian reserve (AMH, antral follicle count) and clinical history.
Antagonist protocols have become the international standard per ESHRE 2019/2024 and NICE NG156: lower OHSS risk, flexible agonist trigger, shorter cycles (10–12 days), better patient experience. Long agonist remains indicated in severe endometriosis, adenomyosis and planned-synchronisation cycles. Mini-IVF and natural cycle are options for poor responders (POSEIDON groups 3–4) and elective fertility preservation.
Every protocol combines three drug classes: recombinant or urinary gonadotrophins (FSH, HMG, LH), GnRH analogues (agonist or antagonist) and a final maturation trigger (hCG or agonist). Doses are tailored to ovarian reserve: low (150–225 IU/day) for high responders and PCOS, high (300–450 IU/day) for poor responders. Monitoring is every 2–3 days with transvaginal ultrasound and oestradiol.
Each protocol page describes: indications, contraindications, average duration, typical drugs, doses, mean oocytes retrieved (CNPMA-reported), cancellation rate, OHSS risk, medication cost (€800–€2,500) and references. It links to the cost calculator and to the matching IVF or ICSI guide.
Before your consultation, read the proposed protocol and bring questions: why this one for me, what alternatives exist, predicted dose, calculated OHSS risk, expected oocyte yield, plan if response is poor. Especially useful for second opinions. All information in this hub is editorially independent and cross-checked against official sources — CNPMA, Portuguese DGS, SNS, ERS and Law 32/2006. Best-practice recommendations follow European ESHRE and UK NICE NG156 guidance.
Hub FAQs
- Can I choose my protocol?
- Selection is clinical and individualised. You can (and should) ask for a reasoned explanation and a second opinion if you disagree.
- Most common Portuguese protocol?
- Antagonist — over 70% of cycles in 2024 across licensed centres.
- Does protocol affect success rate?
- Marginally in normal responders. In poor or high responders the choice is decisive.
- Is mini-IVF worth it?
- Cost-effective in very low AMH or advanced age. Not a universal alternative.
- Is long agonist still used?
- Yes, in selected cases — severe endometriosis, adenomyosis, FET synchronisation. Not first-line for standard cycles.