Awonuga AO, et al. - In this study, researchers assessed whether continued stimulation of mature follicles to allow “catch up” growth of medium-sized follicles in assisted reproductive technology compromises the clinical pregnancy (CPR) and live birth (LBR) rates in IVF/ICSI cycles. As per observations, delaying hCG administration to allow further growth of the medium-sized follicles added further days of superovulation and cost, but, there appeared no improvement in CPR and LBR with this delay.

Methods

• 200 first IVF ± ICSI cycles out of a total of 340 cycles with complete data were reviewed in this retrospective cohort study.
• Gonadotropins (Gn) and GnRH antagonist were included in stimulation protocols of the women.
• Researchers divided treatment cycles into two groups (Gp): hCG administration delayed despite the presence of two mature follicles, defined as ≥ 18 mm [Gp1, n = 79] and hCG administration given when there were two mature follicles [Gp2, n = 121].

Results

• In Gp1, the patients were markedly younger than those in Gp2 [32.9 (4.5) vs. 34.3 (4.8), p = 0.04] and required a median of one more day of superovulation before ovulation was triggered with hCG.
• The extra days seemed associated with the use of 450 [75–2025] more Gn, such that at the time the hCG was administered, patient’s in group 1 had developed significantly greater number of follicles ≥ 18 mm [mean (SD), 4.9 (1.8) vs. 3.4 (1.7), p < 0.0001].
• The two groups were similar regarding the clinical pregnancy (48.1 vs. 38.0%, [OR (95% CI)] [1.6 (1.0–2.5), p = 0.09]) and live birth (43.0 vs. 35.5%, [1.4 (0.9–2.3), p = 0.21]) rates per cycle started.
• As per forward stepwise logistic regression, only maternal age (p = 0.04) influenced clinical pregnancy rates (OR = 0.88, CI 0.78–0.99) and only the number of days for superovulation influenced live birth rates (OR = 0.65, CI 0.486–0.869).