Journal Article

A 38 h interval between hCG priming and oocyte retrieval increases <i>in vivo</i> and <i>in vitro</i> oocyte maturation rate in programmed IVM cycles†

Weon-Young Son, Jin-Tae Chung, Ri-Cheng Chian, Belen Herrero, Ezgi Demirtas, Shai Elizur, Yariv Gidoni, Camille Sylvestre, Nicola Dean and Seang Lin Tan

in Human Reproduction

Published on behalf of European Society of Human Reproduction and Embryology

Volume 23, issue 9, pages 2010-2016
Published in print September 2008 | ISSN: 0268-1161
Published online June 2008 | e-ISSN: 1460-2350 | DOI:
A 38 h interval between hCG priming and oocyte retrieval increases in vivo and in vitro oocyte maturation rate in programmed IVM cycles†

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Our aim was to evaluate whether extending the interval between human chorionic gonadotrophin (hCG) priming and immature oocyte retrieval increases the oocyte maturation rate following in vitro maturation (IVM).


This study was performed retrospectively. IVM was performed on 113 polycystic ovary syndrome patients (n = 120 cycles). Oocyte collection was performed either 35 h (Group 1; n = 76) or 38 h (Group 2; n = 44) after 10 000 IU of hCG priming. Following oocyte retrieval, oocyte maturity was assessed and the remaining immature oocytes were cultured in IVM medium up to Day 2.


The number of in vivo matured oocytes collected was significantly higher in Group 2 (13.6%, 114/840 versus 7.3%, 96/1312 in Group 1) (P < 0.01); the oocyte maturation rate after Day 1 was significantly higher (P < 0.01) in Group 2 (46.3 versus 36.0% in Group 1); and clinical pregnancy (40.9 versus 25%) and implantation rates (15.6 versus 9.6%) were better in Group 2 than those in Group 1.


The results suggest that extending the period of hCG priming time from 35 to 38 h for immature oocyte retrieval promotes oocyte maturation in vivo and increases the IVM rate of immature oocytes. Therefore, oocyte retrieval after 38 h of hCG priming may improve subsequent pregnancy outcome in cycles programmed for IVM treatment.

Keywords: hCG priming; in vitro maturation (IVM); oocyte collection time; polycystic ovarian syndrome (PCOS); pregnancy

Journal Article.  5072 words.  Illustrated.

Subjects: Reproductive Medicine

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