Bergh C, Broden H, Lundin K, Hamberger L
Department of Obstetrics and Gynaecology, Sahlgrenska Hospital, Göteborg University, Sweden.
Hum Reprod. 1998 Jul;13(7):1912-5. doi: 10.1093/humrep/13.7.1912.
Ovarian stimulation for in-vitro fertilization (IVF) causes development of several cohorts of follicles. At the time of oocyte collection, oocytes are thus retrieved from a wide range of follicles of different sizes and developmental stages. A relationship between size of follicles and pregnancy rates has earlier been demonstrated. The aim of the present study was to compare fertilization, cleavage and pregnancy rates between oocytes retrieved from large and small follicles in conventional IVF and intracytoplasmic sperm injection (ICSI). A total of 200 conventional IVF patients and 175 ICSI patients underwent oocyte retrieval where oocytes from both large and small follicles were collected. A follicle with a volume of > or = 2 ml, corresponding to a follicular diameter > or = 16 mm as determined by ultrasound, was regarded as a large follicle. Only one cycle from each patient was included. Fertilization and cleavage rates were calculated per patient for oocytes from large and small follicles. The mean fertilization and cleavage rates for conventional IVF and ICSI cycles were calculated. Comparison of pregnancy rates was performed for patients receiving embryos derived from oocytes of only large or only small follicles. For conventional IVF patients, fertilization rates were 71.4 and 58.1% (P < 0.01, Wilcoxon paired test) for oocytes of large and small follicles respectively. The corresponding cleavage rates were 95.4 and 93.9% respectively. The pregnancy rate for the two groups was 47% (60/127) and 15% (2/13) (P < 0.05, chi2 test). For ICSI patients the fertilization rate was 72.0 and 71.1% for oocytes of large and small follicles respectively. The corresponding cleavage rate was 93.0 and 91.1%. The pregnancy rate in the two groups was 41% (46/113) and 42% (5/12). The results show that oocytes from smaller follicles also yield fertilization and pregnancies, although in conventional IVF to a lesser extent than oocytes from larger follicles. For IVF cycles, a higher proportion of immature oocytes (which are normally not included in the ICSI procedure) in the group of oocytes from small follicles is most probably the explanation for the lower fertilization rate. The decrease in pregnancy rate with oocytes from small follicles in the IVF cycles was not observed in the ICSI cycles. The possibility of evaluating the degree of oocyte maturation prior to fertilization may be an advantage of the ICSI technique. This suggests that the disadvantages of oocytes from small follicles might be overcome by means of ICSI.
用于体外受精（IVF）的卵巢刺激会促使多个卵泡群发育。因此，在采集卵母细胞时，会从各种大小和发育阶段不同的卵泡中获取卵母细胞。卵泡大小与妊娠率之间的关系此前已得到证实。本研究的目的是比较在常规IVF和卵胞浆内单精子注射（ICSI）中，从大卵泡和小卵泡中获取的卵母细胞的受精率、卵裂率和妊娠率。共有200例常规IVF患者和175例ICSI患者接受了卵母细胞采集，采集了大卵泡和小卵泡中的卵母细胞。体积≥2 ml的卵泡，经超声测定其卵泡直径≥16 mm，被视为大卵泡。每位患者仅纳入一个周期。计算每位患者大卵泡和小卵泡中卵母细胞的受精率和卵裂率。计算常规IVF和ICSI周期的平均受精率和卵裂率。对仅接受来自大卵泡或仅来自小卵泡的卵母细胞所衍生胚胎的患者进行妊娠率比较。对于常规IVF患者，大卵泡和小卵泡中卵母细胞的受精率分别为71.4%和58.1%（P<0.01，Wilcoxon配对检验）。相应的卵裂率分别为95.4%和93.9%。两组的妊娠率分别为47%（60/127）和15%（2/13）（P<0.05，卡方检验）。对于ICSI患者，大卵泡和小卵泡中卵母细胞的受精率分别为72.0%和71.1%。相应的卵裂率为93.0%和91.1%。两组的妊娠率分别为41%（46/113）和42%（5/12）。结果表明，较小卵泡中的卵母细胞也能实现受精和妊娠，尽管在常规IVF中程度低于较大卵泡中的卵母细胞。对于IVF周期，小卵泡组卵母细胞中未成熟卵母细胞比例较高（通常ICSI程序不包括这些未成熟卵母细胞）很可能是受精率较低的原因。在ICSI周期中未观察到IVF周期中小卵泡卵母细胞妊娠率的下降。在受精前评估卵母细胞成熟程度的可能性可能是ICSI技术的一个优势。这表明通过ICSI可能克服小卵泡卵母细胞的劣势。
