The effect of follicular dominance on oocyte recovery rate and on the clinical outcome of IVM treatment in non-hCG-primed patients with PCOS.

Introduction: The importance of the emergence of a dominant follicle prior
to hCG administration and oocyte retrieval in IVM treatment has been well
documented. However, the effect of follicular dominance in non-hCG-primed
IVM cycles in PCOS patients has not been investigated. The aim of this study
was to examine the influence of the presence of a follicle of more than 9 mm
diameter on the oocyte recovery rate and on the clinical outcome in non-hCGprimed
IVM cycles.
Material and Methods: Between January and December 2010, 96 IVM-treatment
cycles were performed at UZ Brussel in 53 patients with PCOS. Patients
received small doses of uFSH or HP-HMG from day 3 of the cycle for a
few days. When the largest follicle reached 10-11 mm and/or when endometrial
thickness was at least 5 mm, the oocyte retrieval was scheduled on the following
day. Cumulus oocytes complexes (COCs) were retrieved and cultured in
IVM culture media (Origio) for 38 hrs at 5% CO2 and 20% O2. Cycles were
divided into two categories according to the presence or absence of a dominant
follicle (group 1: a dominant follicle, measuring ? 9 mm (40 cycles); group 2:
no dominant follicle, all follicles measuring ? 9 mm (56 cycles)). Recovery
rate, maturation rate and clinical outcome were analyzed. All data were analyzed
using Student's t-test and chi-square test.
Results: 96 cycles IVM cycles yielded 1303 COCs (404 COCs in group 1 and
899 COCs in group 2). A mean number of 28.4 ± 12.9 and 36.2 ± 13.7 follicles
were punctured in groups 1 and 2, respectively (p = 0.024). The mean number
of collected COCs per cycle was 10.2 ± 5.6 in group 1 and 15.9 ± 9.1 in group 2
(p <0.001). When a dominant follicle was present, the maturation rate per cycle
(5.9 ± 4.3 MII oocytes in group 1) was significantly worse compared to cycles
without a dominant follicle (7.8 ± 4.9 MII oocytes in group 2, p = 0.045). Fertilisation
rates (4.13 ± 3.2; 5.02 ± 3.1), the number of good quality embryos on
transfer day 3 (1.84 ± 1.75; 2.47 ± 1.99) and the number of transferred embryos
per cycle (1.28 ± 0.45; 1.39 ± 0.49) were not significantly different in the two
groups. The clinical pregnancy rates in fresh cycles were 7% (2/29) and 13.8%
(5/36) in groups 1 and 2, respectively.
Conclusion: The presence of a dominant follicle in non-hCG-primed IVM cycles
in PCOS patients results in lower oocyte recovery rates and lower maturation
rates. Although the developmental competence of the resulting embryo is
apparently unaffected by follicular dominance, the observed tendency
toward lower pregnancy rates in cycles with a dominant follicle deserves further
scrutiny.