Patient-Friendly IVF / Understanding Progestin Primed Ovarian Stimulation (PPOS)

Many IVF patients have concerns about the number of injections required during treatment. Injections can be uncomfortable, cause skin bruising, and require careful administration over several days. Conventional IVF protocols typically involve daily injections for 10 to 14 days, which may be challenging for some individuals.

Progestin Primed Ovarian Stimulation (PPOS) is an alternative approach that reduces the number of injections while maintaining treatment effectiveness. This article outlines the key aspects of PPOS, its benefits, and considerations for patients.

Why Are IVF Injections Necessary?

IVF treatment involves medications that stimulate egg development and regulate ovulation timing. There are two main types of injections used in standard IVF cycles:

• Follicle-Stimulating Hormone (FSH): Stimulates the ovaries to produce multiple eggs for retrieval.
• GnRH Antagonist: Prevents premature ovulation before egg retrieval.

In an average IVF cycle, patients receive injections of both medications (FSH and GnRH antagonist) for up to two weeks. While effective, this regimen may be demanding for those with injection-related concerns.

Potential Ways to Reduce the Number of IVF Injections?

Advancements in IVF drugs can help to reduce the number of injections required by using the two types of medications in IVF stimulation regimen.

1. Long-acting FSH injections – A single injection of long-acting FSH releases hormones gradually over seven days, reducing the need for daily injections.
2. Replacement of injections by oral medication – An oral tablet (progesterone) is used as an alternative for GnRH antagonist injection – to prevent early release of eggs.

With these adjustments, the total number of injections per cycle can decrease from an average of 15–20 to approximately five.

How Progestin Primed Ovarian Stimulation (PPOS) Works

PPOS modifies the traditional IVF stimulation protocol by reducing the number of injections required. This is achieved through:

• Oral progesterone instead of GnRH antagonist injections – In PPOS, oral progesterone tablets replace daily injections used to prevent premature ovulation.

Who Can Consider PPOS?

PPOS may be suitable for:

• Individuals undergoing elective egg freezing – Since fresh embryo transfer is not an option in PPOS, this approach aligns with planned cryopreservation.
• Patients undergoing fertility preservation before medical treatment – Those requiring chemotherapy or other treatments affecting fertility may benefit from a protocol where all embryos are frozen.
• Cases requiring frozen embryo transfer (FET) – If embryo transfer is already planned for a later date, PPOS may be considered.
• Patients seeking fewer injections – Those who prefer a protocol with reduced injections may find PPOS a more manageable option.

However, PPOS may not be suitable for every patient. Some individuals may not respond effectively to long-acting FSH, and fresh embryo transfer is not possible under this protocol. A consultation with a fertility specialist is necessary to determine suitability.

Considerations for PPOS in IVF Treatment

While PPOS offers a modified approach, several factors should be evaluated:

• Ovarian response – Some patients may require specific adjustments in stimulation medications.
• Embryo transfer planning – Since fresh transfer is not possible, patients must be prepared for a freeze-all approach.
• Medication cost – While reducing the number of injections, medication pricing varies based on individual protocols.

At Alpha Fertility Center, specialists assess each patient’s case to determine the most appropriate treatment approach.

Consult Alpha Fertility Center for More Information

Meet Our Fertility Specialists

Dr Chua Ka-Hee

Consultant Obstetrician & Gynaecologist, Fertility Specialist

MBBS (Singapore), MRCOG (UK)