Duostim Detailed Protocol

Dual Stimulation (DuoStim) – Detailed Clinical Protocol

What is Dual Stimulation (DuoStim)?

DuoStim is the process of developing and collecting (OPU) two separate sets of eggs in both the follicular and luteal phases within the same menstrual cycle. The aim is to obtain more oocytes in a short period, especially in patients with low ovarian reserve.

In Which Patients Is It Preferred?

• Low AMH / poor responder
• Advanced age (>38)
• Time-constrained patients (oncofertility)
• Low oocyte count in previous cycles

Basic Principle

After the follicular phase, a new wave of follicles also forms in the luteal phase. A second stimulation is performed using this wave.

1. Follicular Phase Stimulation

Starts on day 2–3 of menstruation.
• rFSH or hMG: 225–300 IU/day
• GnRH antagonist added on day 5–6
• Trigger when follicles are 18–20 mm

Trigger (Ovulation Induction)

• GnRH agonist trigger (according to OHSS risk)
• or low-dose hCG
• OPU 34–36 hours later

1. OPU (Egg Retrieval)

• First eggs are collected
• All embryos are usually frozen (freeze-all)

2. Start of Luteal Phase Stimulation

• Starts 3–5 days after the first OPU
• Stimulation is possible despite high progesterone

Luteal Phase Stimulation Protocol

• rFSH / hMG: 225–300 IU
• GnRH antagonist is usually not required
• Alternative: progesterone protocol

Monitoring in the Luteal Phase

• Follicle growth is monitored by ultrasound
• Usually 8–10 days of stimulation

2. Trigger

• GnRH agonist is generally preferred
• Second OPU 34–36 hours later

2. OPU

• Second group of oocytes is collected
• Embryos are again frozen

Embryo Transfer Strategy

• Freeze-all approach
• Transfer after preparation in the next cycle

Advantages

• More oocytes in a short time
• Saves time
• Significant advantage in poor responder patients

Disadvantages

• More intensive treatment
• Increased cost
• Patient compliance is important

Impact on Success

It can increase the cumulative pregnancy rate by increasing the total number of oocytes.

Clinical Tips

• If there is a low response in the first cycle, DuoStim can be considered immediately
• Low AMH + advanced age → strong candidate
• Endometrial preparation should be planned separately

Conclusion

DuoStim is a game-changing protocol, especially for patients with low ovarian reserve. It provides significant advantages with proper patient selection.