Research Article| Volume 159, ISSUE 1, P143-147, November 2011

Triggering final oocyte maturation with reduced doses of hCG in IVF/ICSI: a prospective, randomized and controlled study



      To compare the effectiveness of urinary human chorionic gonadotropin (u-hCG) at reduced doses of 4000 IU and 6000 IU in inducing final oocyte maturation during in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) cycles.

      Study design

      164 patients with an indication for IVF or ICSI recruited in this randomized, single-blinded and controlled study in IVF clinic at the Sun Yat-sen Memorial Hospital. Patients were prospectively randomized to receive 4000 IU (Group A, n = 83) and 6000 IU (Group B, n = 81) of hCG for triggering final oocyte maturation. Number or percentage of mature oocytes retrieved per patient, fertilization rates, pregnancy rates were the main outcome measures.


      No evidence of statistically significant difference in the number or proportion of mature oocytes retrieved was observed in both groups. The lower fertilization rate and significantly lower clinical pregnancy rate were observed in Group A. The ovarian hyperstimulation syndrome (OHSS) rates in both groups were also similar. In the subgroup of BMI < 20 kg/m2, fertilization rate were significantly higher in the administration group of hCG at the dose of 6000 IU when compared with the dose of 4000 IU (82.40% vs. 70.92%, P = 0.017); in contrast, no significant difference in clinical pregnancy rates was observed in both groups. In the subgroup of BMI 20–25 kg/m2, clinical pregnancy rates were significantly higher in patients treated with hCG at dose of 6000 IU than patients treated with hCG at dose of 4000 IU (65.3% vs. 35.0%, P = 0.004); however, no significant difference in fertilization rates was observed.


      Both doses of u-hCG revealed an equal effect on the induction of final oocyte maturation in the patients with moderate or high ovarian response; however, the reduced dose of hCG could result in an obvious impact on clinical pregnancy rates and did not exhibit an obvious effect on OHSS rates.


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        • Licht P.
        • Russu V.
        • Wildt L.
        On the role of human chorionic gonadotropin (hCG) in the embryo-endometrial microenvironment: implications for differentiation and implantation.
        Semin Reprod Med. 2001; 19: 037-048
        • Delvigne A.
        • Rozenberg S.
        Epidemiology and prevention of ovarian hyperstimulation syndrome (OHSS): a review.
        Hum Reprod Update. 2002; 8: 559-577
        • Ludwig M.
        • Doody K.J.
        • Doody K.M.
        Use of recombinant human chorionic gonadotropin in ovulation induction.
        Fertil Steril. 2003; 79: 1053-1058
        • Zelinski-Wooten M.B.
        • Hutchison J.S.
        • Trinchard-Lugan I.
        • Hess D.L.
        • Wolf D.P.
        • Stouffer R.L.
        Initiation of periovulatory events in gonadotrophin-stimulated macaques with varying doses of recombinant human chorionic gonadotrophin.
        Hum Reprod. 1997; 12: 1877-1885
        • Yuan A.N.
        • Jing Z.H.U.
        • Yong-mei G.U.A.N.
        The effect of low-dose hCG in high responders on the results of IVF.
        J Harbin Med Univ. 2009; 43: 282-284
        • Schmidt D.W.
        • Maier D.B.
        • Nulsen J.C.
        • Benadiva C.A.
        Reducing the dose of human chorionic gonadotropin in high responders does not affect the outcomes of in vitro fertilization.
        Fertil Steril. 2004; 82: 841-846
        • Nargund G.
        • Hutchison L.
        • Scaramuzzi R.
        • et al.
        Low-dose HCG is useful in preventing OHSS in high-risk women without adversely affecting the outcome of IVF cycles.
        Reprod Biomed Online. 2007; 14: 682-685
        • Golan A.
        • Weissman A.
        Symposium: update on prediction and management of OHSS. A modern classification of OHSS.
        Reprod Biomed Online. 2009; 19: 28-32
        • Aboulghar M.
        Prediction of ovarian hyperstimulation syndrome (OHSS). Estradiol level has an important role in the prediction of OHSS.
        Hum Reprod. 2003; 18: 1140-1141
        • Chan Carina C.W.
        • Ng Ernest H.Y.
        • Chan Maureen M.Y.
        • et al.
        Bioavailability of hCG after intramuscular or subcutaneous injection in obese and non-obese women.
        Hum Reprod. 2003; 18: 2294-2297
        • Chan C.C.
        • Ng E.H.
        • Tang O.S.
        • Yeung W.S.
        • Lau E.Y.
        • Ho P.C.
        A prospective randomized double-blind study to compare two doses of recombinant human chorionic gonadotrophin in inducing final oocyte maturity and the hormonal profile during the luteal phase.
        J Clin Endocr Metab. 2005; : 2004-2169
        • Verwoerd G.R.
        • Mathews T.
        • Brinsden P.R.
        Optimal follicle and oocyte numbers for cryopreservation of all embryos in IVF cycles at risk of OHSS.
        Reprod Biomed Online. 2008; 17: 312-317
        • Jayaprakasan K.
        • Herbert M.
        • Moody E.
        • Stewart J.A.
        • Murdoch A.P.
        Estimating the risks of ovarian hyperstimulation syndrome (OHSS): implications for egg donation for research.
        Hum Fertil (Camb). 2007; 10: 183-187
        • Mocanu E.
        • Redmond M.L.
        • Hennelly B.
        • Collins C.
        • Harrison R.
        Odds of ovarian hyperstimulation syndrome (OHSS) – time for reassessment.
        Hum Fertil (Camb). 2007; 10: 175-181
        • Lin H.
        • Zhang Q.
        • Li Y.
        • et al.
        Different doses of HCG for oocyte maturation: the effect on the outcome of IVF-ET.
        Guangdong Med J. 2009; 30: 1686-1687