Should You Switch the Ovarian Stimulation Protocol After an IVF Cycle Is Cancelled for Follicular Asynchrony?

OBGYN JOURNAL WATCH

Fertility & Reproductive Medicine Update | June 2026

Should You Switch the Ovarian Stimulation Protocol After an IVF Cycle Is Cancelled for Follicular Asynchrony?

Article

Hochberg A, Hincapie M, Amikam U, Kugelman N, Buckett W, Reinblatt S. The effect of ovarian stimulation protocol on follicular asynchrony during in vitro fertilization – A retrospective cohort study. International Journal of Gynecology & Obstetrics. Published online June 24, 2026. doi:10.1002/ijgo.71186

🎯 Why This Study Matters

Follicular asynchrony—uneven growth of ovarian follicles during controlled ovarian stimulation (COS)—is a common reason for IVF cycle cancellation. Poor synchronization reduces the proportion of mature oocytes available for retrieval, potentially compromising embryo yield and overall IVF success.

This study evaluated whether changing the COS protocol after a cancelled cycle improves follicular synchrony in the subsequent IVF attempt.

📖 Study Design

• Design: Single-center retrospective cohort study

• Study period: January 2018 – March 2024

• Participants: 95 women with an IVF cycle cancelled because of follicular asynchrony followed by a subsequent oocyte retrieval (OPU) cycle.

• Groups:

  • Group 1: Same COS protocol repeated (n=43)

  • Group 2: Different COS protocol used (n=52)

Primary Outcome

Improvement in follicular maturation rate, defined as the difference in the proportion of follicles ≥14 mm between the cancelled cycle and the subsequent OPU cycle.

🔑 Key Findings

✅ Switching protocols improved follicular synchrony

Women whose stimulation protocol was changed demonstrated significantly greater improvement in follicular maturation.

• Follicular maturation rate improvement

  
  

  • Same protocol: 0.17 (IQR 0.05–0.28)

  • Switched protocol: 0.30 (IQR 0.15–0.39)

  • p = 0.03

✅ After adjustment for confounding variables

Analysis adjusting for parity, AFC, endometriosis and recombinant LH dose showed:

• Protocol change remained the only independent predictor of improved follicular maturation.

Least Squares Mean Improvement

• Different protocol: 0.27

• Same protocol: 0.12

p = 0.01

✅ Asynchrony may still persist

Despite protocol modification, some patients continued to demonstrate follicular asynchrony during the subsequent IVF cycle, suggesting that patient-specific biological factors also contribute.

🧠 Clinical Pearls

✔ Patients with IVF cancellation due to follicular asynchrony may benefit from changing the stimulation protocol in the next cycle.

✔ Long GnRH agonist protocols may improve follicular synchrony by achieving greater pituitary suppression and more uniform follicular recruitment.

✔ Follicular maturation rate may serve as a useful surrogate marker when mature oocyte data are unavailable due to cycle cancellation.

✔ Protocol modification should be individualized based on ovarian reserve, previous response, age and infertility diagnosis.

📊 Strengths

• Novel assessment of follicular maturation after cancelled IVF cycles.

• Real-world clinical cohort.

• Adjustment for important confounding variables.

• Provides practical guidance for difficult IVF management decisions.

⚠ Limitations

• Retrospective single-center study.

• Small sample size (95 patients).

• Follicular maturation rate is a surrogate outcome rather than a validated clinical endpoint.

• No direct evidence that protocol switching improves pregnancy or live birth rates.

• Results cannot identify the optimal protocol change because multiple protocol combinations were analyzed together.

🩺 Clinical Implications

Changing the ovarian stimulation protocol after cancellation for follicular asynchrony resulted in approximately 13% more recruited follicles reaching estimated maturity compared with repeating the same protocol.

Although encouraging, these findings should not be interpreted as evidence for improved embryo quality or live birth rates. Prospective randomized studies are needed before protocol switching becomes standard practice.

⭐ Bottom Line

For women whose IVF cycle is cancelled because of marked follicular asynchrony, switching the controlled ovarian stimulation protocol appears to improve follicular synchrony in the subsequent cycle. While this strategy may increase the proportion of mature follicles available for retrieval, its effect on pregnancy and live birth outcomes remains uncertain. Clinicians should individualize protocol selection while awaiting higher-quality prospective evidence.

📚 References

1. Hochberg A, Hincapie M, Amikam U, Kugelman N, Buckett W, Reinblatt S. The effect of ovarian stimulation protocol on follicular asynchrony during in vitro fertilization – A retrospective cohort study. International Journal of Gynecology & Obstetrics. Published online June 24, 2026. doi:10.1002/ijgo.71186.

2. Humaidan P, Alviggi C, Fischer R, Esteves SC. The novel POSEIDON stratification of low prognosis patients in assisted reproductive technology and its proposed marker of successful outcome. Reproductive Biomedicine Online. 2016;32:24–31.

3. Bosch E, Labarta E, Kolibianakis E, Rosen M, Meldrum D. Regimen of ovarian stimulation affects oocyte and embryo quality. Fertility and Sterility. 2016.

4. Drakopoulos P, Blockeel C, Stoop D, et al. Conventional ovarian stimulation and individualized treatment strategies in IVF. Human Reproduction Update. 2016.

5. ESHRE Guideline Group on Ovarian Stimulation. ESHRE Guideline: Ovarian Stimulation for IVF/ICSI. European Society of Human Reproduction and Embryology.