Pregnancy with oocytes characterized by narrow perivitelline space and heterogeneous zona pellucida: is intracytoplasmic sperm injection necessary?

PURPOSE: This retrospective study analyzed fertilization protocols and pregnancy outcomes for oocytes with with narrow perivitelline space and heterogeneous zona pellucid (NPVS/HZP). METHODS: In 63 in-vitro fertilization cycles filled with NPVS/HZP oocytes (abnormal oocytes group) and 521 cycles with normal oocytes (normal oocytes group), major clinical and laboratory parameters were recorded and compared in different fertilization cycles (conventional IVF cycles, rescue ICSI cycles, and traditional ICSI cycles). RESULTS: NPVS/HZP oocytes meant lower MIIoocytes rates in both IVF and ICSI cycles compared with normal oocytes (p < 0.05). The 2PN rates for abnormal oocytes were significantly lower than those for normal oocytes in both conventional IVF cycles (58.8% VS 71.3%, P < 0.05) and rescue ICSI cycles (58.0% VS 78.0%, P = 0.0000). The high-quality embryo rates in normal oocytes groups were significantly higher than those in abnormal oocytes groups in different fertilization cycles (52.2% VS 35.0%, P < 0.01; 42.9% VS 23.9%, P < 0.001; 50.6% VS 31.0%, P = 0.0000, respectively). No clinical pregnancy was obtained from abnormal oocytes in 11 conventional IVF cycles. The clinical pregnancy rates in rescue ICSI and traditional ICSI cycles were comparatively lower in abnormal oocytes groups, but there was no significant difference as compared with normal oocytes groups (35.0% VS 48.1% and 26.7% VS 50.7%, P > 0.05, respectively). CONCLUSIONS: Retrieval of oocytes characterized by NPVS/PZP from cycle to cycle was one of the reasons for obscure infertility. ICSI may be the right way to avoid fertilization failure and get pregnancy in women with NPVS/HZP oocytes.

Elective single blastocyst transfer is more suitable for normal responders than for high responders.

BACKGROUND: Embryo quality and receptivity of the endometrium are two factors that determine the results of in vitro fertilization/intra-cytoplasmic sperm injection-embryo transfer (IVF/ICSI-ET). There is no consensus of the optimal transfer strategy for normal responders or high responders. The current study aimed to find the optimal transfer strategy for different subgroups of patients. METHODS: From April 2010 to December 2010, patients who meet the following criteria were included in this study; primary infertility, female age ≤ 35 years, FSH level on female cycle day 2 - 3 ≤ 12 mIU/ml, at least six good quality embryos available on day three. The clinical outcomes using different transfer strategies between normal responders and high responders were reviewed and compared. RESULTS: For the normal responders, the clinical pregnancy rate of day three double-embryo transfer (DET) was comparable to that of day five elective single blastocyst transfer (eSBT), 64.04% vs. 60.33% (P > 0.05). For the high responders, the clinical pregnancy rate of day five eSBT was significantly lower than that of day three DET, 43.35% vs. 57.21% (P < 0.05). For the high responders, the rates of clinical pregnancy and implantation in frozen-thawed embryo transfer (FET) cycles were notably higher than in eSBT cycles (64.56% vs. 43.35% and 62.11% vs. 43.35% respectively) (P < 0.05). CONCLUSIONS: For normal responders, eSBT might be an applicable strategy to reduce multiple pregnancy rates while maintaining acceptable overall pregnancy rates. And in order to reduce multiple pregnancies and increase the chance of pregnancy of high responders, FET may be a preferable strategy.