Table 1 Main characteristics of studies evaluating the effect of stimulation phase length on ICSI outcomes
Study/design | Patients | Stimulation protocol | Study groups | Criteria used for triggering ovulation | Statistically significant results (p < 0.05) |
|---|---|---|---|---|---|
Martin et al. [16] Retrospective | 555 IVF/ICSI cycles from 460 women | Long agonist protocol | G1: 6–9, G2: 10–11 and G3: 12 or more days of stimulation | At least 3 follicles ≥ 18 in mean diameter | Fewer oocytes retrieved in group 3. No diff. in IR, CPR, and OPR |
Chuang et al. [17] Retrospective | 794 cycles from 545 women | Long agonist, flare, or antagonist protocols | G1: ≤ 9 days, G2: 10–12 and G3: 13 or more days of stimulation | Minimum of 2 follicles ≥ 17 mm in mean diameter | On multivariate analysis, cycles with SPL ≥ 13 days were associated with significantly lower CPR and LBR |
Ryan et al. [24] Prospective | 663 women | Long agonist, flare, or antagonist protocols | G1: SPL ≥ 13 days G2: SPL < 13 days | hCG was used as a trigger when at least 3 follicles ≥ 18 mm and the majority of the cohort above 14 mm | CPR was dramatically decreased when SPL is 13 days or longer |
Alport et al. (2011) [25] Retrospective | 140 normal responder women | Long agonist and antagonist protocol | G1: SPL < 10, G2: 10–12 and G3: 12 or more days | When > 3 follicles reached > 17 mm, 10,000 IU u-hCG were administrated | SPL of 11 days was associated with the optimum number of follicles and oocytes. No difference in IR and CPR |
Mardesic et al. [18] Retrospective | 1448 women | Antagonist | Early responders (received hCG prior to or on day 8) and Normal responders (received hCG after day 8) | hCG was administrated when at least 3 follicles ≥ 17 mm in mean diameter | No difference in the number of oocytes retrieved and OPR between the two groups |
Purandare et al. (2016) [26] Retrospective | 10,487 IVF/ICSI cycles | Long agonist, flare, or antagonist protocols | Patients arranged from the shortest stimulation period (7 days) to the longest period (16 days) | hCG was administrated when at least 2–3 follicles ≥ 18 mm in diameter | No difference in CPR in both IVF and ICSI cycles with all used protocols |
Deepmala et al. (2019) [27] Prospective | 136 women | Long agonist and antagonist protocol | Short SPL (< 10 days), medium (10–12 days), and long (> 12 days) | Rec-hCG was administrated when at least 3 follicles ≥ 18 mm in mean diameter | Peak follicles, oocytes retrieved, MII oocytes were found at 11 days of stimulation then falls. No difference in fertilization, implantation, and pregnancy rates |