ABSTRACT
Transvaginal ultrasound-guided aspiration is performed using a 19G aspiration needle (Cook, Eight Mile Plains, Queensland, Australia). A portable aspiration pump is connected to the aspiration needle with a pressure between 80 and 100 mmHg. The aspirates are collected in tubes (10 ml) containing prewarmed heparinized flushing medium (Ham’s F-10 medium) buffered with Hepes. Cumulus-oocyte complexes (COCs) are isolated by filtering the follicular aspirates through a mesh filter (diameter 70 mm, Falcon 1060, USA). In order to remove erythrocytes and small cellular debris, the filtrate is washed with Hepes-buffered Ham’s F-10 medium. The retained COCs are then re-suspended in Ham’s F-10 medium. The atretic and denuded COCs are discarded. The maturity of oocytes at the time of oocyte retrieval is evaluated under a stereomicroscope. Oocyte maturation is assessed by the presence of the first polar body (1PB) in the pelliviteline space (PVS). Mature and immature oocytes can be retrieved at the same time. As shown in Figure 27.1a, the mature oocyte was identified by extrusion of 1PB into PVS,
and Figure 27.1b shows the immature oocyte assessed by containing germinal vesicle (GV) in the cytoplasm. Our experience indicates that the mature oocytes can be retrieved from follicles as small as 10 mm in diameter.
