1. What exactly is PPOS?
PPOS stands for Progestin-Primed Ovarian Stimulation, a modern IVF protocol that uses simple oral tablets called progestins to prevent premature ovulation.
Traditionally, we’ve relied on GnRH agonists ( Luprorin) or GnRH antagonists ( Ovucet) injections to suppress the LH surge and keep eggs growing until they’re ready for retrieval.
PPOS achieves the same effect — but with tablets instead of injections.
In short, it’s a “tablet-based IVF protocol” that offers the same control with greater comfort, flexibility, and often at a lower cost.
2. How does it work?
During a natural cycle, a mid-cycle LH surge triggers ovulation.
In IVF, that LH surge must be tightly controlled — premature ovulation could ruin an entire cycle.
By giving daily progestin tablets (such as medroxyprogesterone acetate , Meprate, 10 mg daily) we keep the pituitary gland gently “asleep.” This blocks the LH surge, allowing follicles to mature safely until we deliberately trigger ovulation.
3. What medications are used in a PPOS cycle?
The treatment typically includes:
Gonadotropins (FSH) : fertility injections( Gonal-F) to stimulate follicle growth.
Progestin tablets: Meprate to suppress premature ovulation.
Trigger injection: an hCG trigger ( Ovitrelle) given when follicles are mature.
No fresh embryo transfer — all embryos are frozen for later use.
4. What does a typical PPOS cycle look like?
This protocol is endorsed by ESHRE 2025 as a valid alternative to GnRH analogues when a freeze-all strategy is planned.
5. What are the advantages of PPOS?
✅ Fewer injections: No daily GnRH shots.
✅ Lower cost: Oral tablets are inexpensive.
✅ Effective suppression: Prevents premature LH surge just as reliably as traditional protocols.
✅ Safer for high responders: Lower risk of OHSS when paired with a freeze-all approach.
✅ Ideal for egg donors & fertility preservation: Simple, safe, predictable, and repeatable.
ESHRE 2025 classifies progestin suppression as “probably equally recommended to GnRH analogues” for cycles where fresh transfer isn’t intended.
6. What are the downsides?
No medical approach is perfect.
The main limitation of PPOS is that fresh embryo transfer isn’t possible — because progesterone exposure during stimulation makes the uterine lining “out of sync.”
Therefore, embryos must be frozen and transferred in a later cycle.
While freezing technology is excellent today (vitrification success > 95 %), this still means an extra step, some waiting time, and slightly higher total cost.
7. Who benefits most from the PPOS protocol?
PPOS is particularly useful for:
Oocyte donors – because no fresh transfer is planned.
Fertility-preservation patients – such as cancer patients or those delaying motherhood.
High responders / PCOS patients – to reduce OHSS risk.
Low-cost cycles – where avoiding expensive antagonists helps.
Clinics using freeze-all strategies as standard practice.
ESHRE 2025 specifically highlights the value of PPOS for elective egg freezing and donor cycles, rating it comparable in safety and efficacy to antagonist regimens.
8. Is PPOS as effective as traditional IVF protocols?
Yes.
Multiple studies and meta-analyses have confirmed that oocyte yield, fertilisation, embryo quality, and pregnancy outcomes are comparable to standard antagonist cycles — when embryos are transferred in frozen cycles.
Success rates depend on factors like age, egg quality, and embryo competence, not the suppression method itself.
9. Is PPOS safe?
Absolutely.
Progestins have been used safely for decades in contraception and luteal-phase support.
The 2025 ESHRE guidelines reaffirm that progestin protocols are safe and effective for preventing premature LH surges in IVF cycles.
Because the protocol involves a planned freeze-all strategy, the risk of OHSS — the most serious IVF complication — becomes negligible.
10. Will taking progestin affect my future fertility or hormones?
No.
Progestin’s suppressive effect is temporary and fully reversible.
Once the medication is stopped, your hormones return to their natural rhythm within days.
Your ovarian reserve and future fertility remain unchanged.
11. Is the embryo quality affected by PPOS?
Evidence shows that embryo quality and euploidy rates are equivalent to those in GnRH-antagonist cycles.
The only difference is timing — embryos are transferred later, not in the same cycle.
This delayed transfer often improves results because the uterine environment in a frozen cycle is calmer and more physiologic.
12. How is luteal support given after a PPOS cycle?
Since no fresh transfer is done, luteal support isn’t required in the stimulation cycle itself.
However, in the subsequent FET cycle, you’ll receive progesterone (vaginal / oral / injectable) and sometimes oestrogen to prepare your uterine lining for implantation.
ESHRE 2025 continues to recommend progesterone as the mainstay of luteal-phase support for all IVF transfers.
13. Is PPOS suitable for everyone?
Not necessarily.
While PPOS is a great option for patients planning freeze-all cycles, it’s not ideal if you wish to do a fresh transfer immediately after egg retrieval.
Your doctor may recommend an antagonist or agonist protocol if you need a fresh transfer for medical or emotional reasons (for example, if embryo freezing isn’t feasible).
14. How do I know which protocol is best for me?
Choosing the right stimulation protocol is a balance of safety, comfort, cost, and clinical outcome.
If you have good ovarian reserve and prefer a tablet-based, less invasive approach, PPOS may be ideal.
If you require a fresh transfer, a GnRH antagonist cycle might be better.
Each decision should be personalised — based on your AMH, AFC, previous response, and overall goals.
15. What do I recommend?
I believe patients should always make informed choices, not be forced into one-size-fits-all protocols.
PPOS is an exciting step toward simplifying IVF without compromising results.
It’s especially empowering for women who want more control, fewer injections, and a cost-effective approach.
Remember — the best IVF plan is one you fully understand and feel comfortable with.
Summary: The Bottom Line
PPOS replaces injectable GnRH analogues with oral progestins.
It offers simpler, safer, and more affordable ovarian stimulation.
Embryos are frozen and transferred later for optimal uterine readiness.
Endorsed by ESHRE 2025 as a viable option in freeze-all strategies.
Perfect for egg donors, fertility preservation, and high responders.
Dr. Malpani: Please get your doubts resolved free using our AI-powered chatbot, built on Dr. Malpani’s 40 years of clinical expertise and experience:https://www.drmalpani.com/chat-w-chatbot/index.html.This will help ensure you’re on the right path, answer your questions whenever you need them, and could potentially save you significant time, money, and unnecessary treatment in the long run.