Individualised controlled ovarian stimulation (iCOS): maximising success rates for assisted reproductive technology patients

Ernesto Bosch, Diego Ezcurra, Ernesto Bosch, Diego Ezcurra

Abstract

Background: In the last two decades, pregnancy rates for patients undergoing in-vitro fertilisation (IVF) have significantly increased. Some of the major advances responsible for this improvement were the introduction of controlled ovarian stimulation (COS) for the induction of multiple follicle development, and the utilisation of mid-luteal gonadotropin-releasing hormone agonists to achieve pituitary down-regulation and full control of the cycle. As a result, a combination of a gonadotropin-releasing hormone agonist with high doses (150-450 IU/day) of recombinant follicle-stimulating hormone has become the current standard approach for ovarian stimulation. However, given the heterogeneity of patients embarking on IVF, and the fact that many different drugs can be used alone or in different combinations (generating multiple potential protocols of controlled ovarian stimulation), we consider the need to identify special populations of patients and adapt treatment protocols accordingly, and to implement a more individualised approach to COS.

Discussion: Studies on mild, minimal and natural IVF cycles have yielded promising results, but have focused on fresh embryo transfers and included relatively young patient populations who generally have the potential for more favourable outcomes. The efficacy of these protocols in patients with a poorer prognosis remains to be tested. When comparing protocols for COS, it is important to think beyond current primary endpoints, and to consider the ideal quality and quantity of oocytes and embryos being produced per stimulated patient, in order to achieve a pregnancy. We should also focus on the cumulative pregnancy rate, which is based on outcomes from fresh and frozen embryos from the same cycle of stimulation. Individualised COS (iCOS) determined by the use of biomarkers to test ovarian reserve has the potential to optimise outcomes and reduce safety issues by adapting treatment protocols according to each patient's specific characteristics. As new objective endocrine, paracrine, functional and/or genetic biomarkers of response are developed, iCOS can be refined further still, and this will be a significant step towards a personalised approach for IVF.

Conclusions: A variety of COS protocols have been adopted, with mixed success, but no single approach is appropriate for all patients within a given population. We suggest that treatment protocols should be adapted for individual patients through iCOS; this approach promises to be one of the first steps towards implementing personalised medicine in reproductive science.

Figures

Figure 1
Figure 1
Relationship between number of oocytes retrieved and ongoing pregnancy rate. Ongoing pregnancy rate according to ovarian response in an unselected population (source: Instituto Valenciano de Infertilidad, between 2004 and 2008, n = 7954, p < 0.000001 [Mantel-Hansen test for trend]).

References

    1. Steptoe PC, Edwards RG. Birth after the reimplantation of a human embryo. Lancet. 1978;12:366.
    1. Trounson AO, Leeton JF, Wood C, Webb J, Wood J. Pregnancies in humans by fertilization in vitro and embryo transfer in the controlled ovulatory cycle. Science. 1981;212:681–682. doi: 10.1126/science.7221557.
    1. Loumaye E. The control of endogenous secretion of LH by gonadotrophin-releasing hormone agonists during ovarian hyperstimulation for in-vitro fertilization and embryo transfer. Hum Reprod. 1990;5:357–376.
    1. Balasch J. In: Female Infertility Therapy: Current Practice. Shoham Z, Jacobs HS, Howles CM, editor. London, UK: Martin Dunitz Ltd; 1998. GnRH agonist protocols: which one to use? pp. 89–203.
    1. Hughes EG, Fedorkow DM, Daya S, Sagle MA, Van de Koppel P, Collins JA. The routine use of gonadotropin-releasing hormone agonists prior to in vitro fertilization and gamete intrafallopian transfer: a meta-analysis of randomized controlled trials. Fertil Steril. 1992;58:888–896.
    1. FIVNAT. French National Register on in vitro fertilization. Contracept Fertil Sex. 1997;25:499–502. 1996 report.
    1. Macklon NS, Stouffer RL, Giudice LC, Fauser BC. The science behind 25 years of ovarian stimulation for in vitro fertilization. Endocr Rev. 2006;27:170–207. doi: 10.1210/er.2005-0015.
    1. Coomarasamy A, Afnan M, Cheema D, van der Veen F, Bossuyt PM, van Wely M. Urinary hMG versus recombinant FSH for controlled ovarian hyperstimulation following an agonist long down-regulation protocol in IVF or ICSI treatment: a systematic review and meta-analysis. Hum Reprod. 2008;23:310–315.
    1. Verberg MF, Eijkemans MJ, Macklon NS, Heijnen EM, Baart EB, Hohmann FP, Fauser BC, Broekmans FJ. The clinical significance of the retrieval of a low number of oocytes following mild ovarian stimulation for IVF: a meta-analysis. Hum Reprod Update. 2009;15:5–12.
    1. Detti L, Williams DB, Robins JC, Maxwell RA, Thomas MA. A comparison of three downregulation approaches for poor responders undergoing in vitro fertilization. Fertil Steril. 2005;84:1401–1405. doi: 10.1016/j.fertnstert.2005.04.053.
    1. Loutradis D, Vomvolaki E, Drakakis P. Poor responder protocols for in-vitro fertilization: options and results. Curr Opin Obstet Gynecol. 2008;20:374–378. doi: 10.1097/GCO.0b013e328305b9b8.
    1. Mochtar MH, Van der Veen, Ziech M, van Wely M. Recombinant Luteinizing Hormone (rLH) for controlled ovarian hyperstimulation in assisted reproductive cycles. Cochrane Database Syst Rev. 2007;18:2.
    1. Bosch E, Labarta E, Crespo J, Simón C, Remohí J, Pellicer A. Impact of luteinizing hormone administration on gonadotropin-releasing hormone antagonist cycles: an age-adjusted analysis. Fertil Steril. 2010. in press .
    1. Fábregues F, Peñarrubia J, Creus M, Manau D, Casals G, Carmona F, Balasch J. Transdermal testosterone may improve ovarian response to gonadotrophins in low-responder IVF patients: a randomized, clinical trial. Hum Reprod. 2009;24:349–359. doi: 10.1093/humrep/den428.
    1. Kim CH, Howles CM, Lee HA. The effect of transdermal testosterone gel pretreatment on controlled ovarian stimulation and IVF outcome in low responders. Fertil Steril. 2010. in press .
    1. Fanchin R, Méndez Lozano DH, Schonäuer LM, Cunha-Filho JS, Frydman R. Hormonal manipulations in the luteal phase to coordinate subsequent antral follicle growth during ovarian stimulation. Reprod Biomed Online. 2005;10:721–728. doi: 10.1016/S1472-6483(10)61115-7.
    1. Garcia-Velasco JA, Moreno L, Pacheco A, Guillén A, Duque L, Requena A, Pellicer A. The aromatase inhibitor letrozole increases the concentration of intraovarian androgens and improves in vitro fertilization outcome in low responder patients: a pilot study. Fertil Steril. 2005;84:82–87. doi: 10.1016/j.fertnstert.2005.01.117.
    1. Verberg MF, Eijkemans MJ, Heijnen EM, Broekmans FJ, de Klerk C, Fauser BC, Macklon NS. Why do couples drop-out from IVF treatment? A prospective cohort study. Hum Reprod. 2008;23:2050–2055. doi: 10.1093/humrep/den219.
    1. Goverde AJ, McDonnell J, Vermeiden JP, Schats R, Rutten FF, Schoemaker J. Intrauterine insemination or in-vitro fertilisation in idiopathic subfertility and male subfertility: a randomised trial and cost-effectiveness analysis. Lancet. 2000;355:13–18. doi: 10.1016/S0140-6736(99)04002-7.
    1. Verberg MF, Macklon NS, Nargund G, Frydman R, Devroey P, Broekmans FJ, Fauser BC. Mild ovarian stimulation for IVF. Hum Reprod Update. 2009;15:13–29.
    1. Frydman R, Cornel C, de Ziegler D, Taieb J, Spitz IM, Bouchard P. Prevention of premature luteinizing hormone and progesterone rise with a gonadotropin-releasing hormone antagonist, Nal-Glu, in controlled ovarian hyperstimulation. Fertil Steril. 1991;56:923–927.
    1. Schipper I, Hop WC, Fauser BC. The follicle-stimulating hormone (FSH) threshold/window concept examined by different interventions with exogenous FSH during the follicular phase of the normal menstrual cycle: duration, rather than magnitude, of FSH increase affects follicle development. J Clin Endocrinol Metab. 1998;83:1292–1298. doi: 10.1210/jc.83.4.1292.
    1. Hohmann FP, Macklon NS, Fauser BC. A randomized comparison of two ovarian stimulation protocols with gonadotropin-releasing hormone (GnRH) antagonist cotreatment for in vitro fertilization commencing recombinant follicle-stimulating hormone on cycle day 2 or 5 with the standard long GnRH agonist protocol. J Clin Endocrinol Metab. 2003;88:166–173. doi: 10.1210/jc.2002-020788.
    1. Baart EB, Martini E, Eijkemans MJ, Van Opstal D, Beckers NG, Verhoeff A, Macklon NS, Fauser BC. Milder ovarian stimulation for in-vitro fertilization reduces aneuploidy in the human preimplantation embryo: a randomized controlled trial. Hum Reprod. 2007;22:980–988. doi: 10.1093/humrep/del484.
    1. de Klerk C, Macklon NS, Heijnen EM, Eijkemans MJ, Fauser BC, Passchier J, Hunfeld JA. The psychological impact of IVF failure after two or more cycles of IVF with a mild versus standard treatment strategy. Hum Reprod. 2007;22:2554–2558. doi: 10.1093/humrep/dem171.
    1. Polinder S, Heijnen EM, Macklon NS, Habbema JD, Fauser BJ, Eijkemans MJ. Cost-effectiveness of a mild compared with a standard strategy for IVF: a randomized comparison using cumulative term live birth as the primary endpoint. Hum Reprod. 2008;23:316–323.
    1. Teramoto S, Kato O. Minimal ovarian stimulation with clomiphene citrate: a large-scale retrospective study. Reprod Biomed Online. 2007;15:134–148. doi: 10.1016/S1472-6483(10)60701-8.
    1. Segawa T, Kato K, Kawachiya S, Takehara Y, Kato O. Evaluation of minimal stimulation IVF with clomiphene citrate and hMG. Fertil Steril. 2007;88:(Suppl 1):S286.
    1. Pelinck MJ, Knol HM, Vogel NE, Arts EG, Simons AH, Heineman MJ, Hoek A. Cumulative pregnancy rates after sequential treatment with modified natural cycle IVF followed by IVF with controlled ovarian stimulation. Hum Reprod. 2008;23:1808–1814. doi: 10.1093/humrep/den155.
    1. Frydman R, Howles CM, Truong F. A double-blind randomized study to compare recombinant human follicle stimulating hormone (FSH; Gonal-F) with highly purified urinary FSH (Metrodin HP) in women undergoing assisted reproductive techniques including intracytoplasmic sperm injection. The French Multicentre Trialists. Hum Reprod. 2000;15:520–525. doi: 10.1093/humrep/15.3.520.
    1. Bergh C, Howles CM, Borg K, Hamberger L, Josefsson B, Nilsson L, Wikland M. Recombinant human Follicle Stimulating Hormone (GONAL-f) versus highly purified urinary FSH (Metrodin HP); results of a randomized comparative study in women undergoing Assisted Reproductive Techniques. Hum Reprod. 1997;12:2133–2139. doi: 10.1093/humrep/12.10.2133.
    1. Al-Inany H, Aboulghar M, Mansour R, Serour G. Meta-analysis of recombinant versus urinary-derived FSH: an update. Human Reproduction. 2003;18:305–313. doi: 10.1093/humrep/deg088.
    1. Min JK, Breheny SA, MacLachlan V, Healy DL. What is the most relevant standard of success in assisted reproduction? The singleton, term gestation, live birth rate per cycle initiated: the BESST endpoint for assisted reproduction. Hum Reprod. 2004;19:3–7. doi: 10.1093/humrep/deh028.
    1. Roberts SA, Fitzgerald CT, Brison DR. Modelling the effect of single embryo transfer in a national health service IVF programme. Hum Reprod. 2009;24:122–131.
    1. Hourvitz A, Machtinger R, Maman E, Baum M, Dor J, Levron J. Assisted reproduction in women over 40 years of age: how old is too old? Reprod Biomed Online. 2009;19:599–603. doi: 10.1016/j.rbmo.2009.04.002.
    1. Barnhart K, Dunsmoor-Su R, Coutifaris C. Effect of endometriosis on in vitro fertilization. Fertil Steril. 2002;77:1148–1155. doi: 10.1016/S0015-0282(02)03112-6.
    1. Heijnen EM, Eijkemans MJ, Hughes EG, Laven JS, Macklon NS, Fauser BC. A meta-analysis of outcomes of conventional IVF in women with polycystic ovary syndrome. Hum Reprod Update. 2006;12:13–21.
    1. Bellver J, Ayllón Y, Ferrando M, Melo M, Goyri E, Pellicer A, Remohí J, Meseguer M. Female obesity impairs in vitro fertilization outcome without affecting embryo quality. Fertil Steril. 2010;93:447–454. doi: 10.1016/j.fertnstert.2008.12.032.
    1. Aspinall MG, Hamermesh RG. Realizing the promise of personalized medicine. Harv Bus Rev. 2007;85:108–117.
    1. Shahine LK, Lamb LD, Lathi RB, Milki AA, Langen E, Westphal LM. Poor prognosis with in vitro fertilisation in Indian women compared to Caucasian women despite similar embryo quality. PLoS ONE. 2009;4:e7599. doi: 10.1371/journal.pone.0007599.
    1. Loutradis D, Patsoula E, Minas V, Koussidis GA, Antsaklis A, Michalas S, Makrigiannakis A. FSH receptor gene polymorphisms have a role for different ovarian response to stimulation in patients entering IVF/ICSI-ET programs. J Assist Reprod Genet. 2006;23:177–184. doi: 10.1007/s10815-005-9015-z.
    1. Mohiyiddeen L, Nardo LG. Single-nucleotide polymorphisms in the FSH receptor gene and ovarian performance: future role in IVF. Hum Fertil (Camb) 2010;13:72–78. doi: 10.3109/14647271003632322.
    1. Alviggi C, Clarizia R, Pettersson K, Mollo A, Humaidan P, Strina I, Coppola M, Ranieri A, D'Uva M, De Placido G. Suboptimal response to GnRHa long protocol is associated with a common LH polymorphism. Reprod Biomed Online. 2009;18:9–14. doi: 10.1016/S1472-6483(10)60418-X.
    1. Lisi F, Rinaldi L, Fishel S, Lisi R, Pepe G, Picconeri MG, Campbell A, Rowe P. Use of recombinant FSH and recombinant LH in multiple follicular stimulation for IVF: a preliminary study. Reprod Biomed Online. 2001;3:190–194. doi: 10.1016/S1472-6483(10)62034-2.
    1. Ruvolo G, Bosco L, Pane A, Morici G, Cittadini E, Roccheri MC. Lower apoptosis rate in human cumulus cells after administration of recombinant luteinizing hormone to women undergoing ovarian stimulation for in vitro fertilization procedures. Fertil Steril. 2007;87:542–546. doi: 10.1016/j.fertnstert.2006.06.059.
    1. Broekmans FJ, Kwee J, Hendriks DJ, Mol BW, Lambalk CB. A systematic review of tests predicting ovarian reserve and IVF outcome. Hum Reprod. 2006;12:685–718. doi: 10.1093/humupd/dml034.
    1. Groome NP, Illingworth PJ, O'Brien M, Pai R, Rodger FE, Mather JP, McNeilly AS. Measurement of dimeric inhibin B throughout the human menstrual cycle. J Clin Endocrinol Metab. 1996;81:1401–1405. doi: 10.1210/jc.81.4.1401.
    1. Ravhon A, Lavery S, Michael S, Donaldson M, Margara R, Trew G. et al.Dynamic assays of inhibin B and oestradiol following buserelin acetate administration as predictors of ovarian response in IVF. Hum Reprod. 2000;15:2297–2301. doi: 10.1093/humrep/15.11.2297.
    1. Bancsi LF, Broekmans FJ, de Jong FH, Habbema JD, te Velde ER. Predictors of poor ovarian response in in vitro fertilization: a prospective study comparing basal markers of ovarian reserve. Fertil Steril. 2002;77:328–336. doi: 10.1016/S0015-0282(01)02983-1.
    1. Seifer DB, Scott RT Jr, Bergh PA, Abrogast LK, Friedman CI, Mack CK, Danforth DR. Women with declining ovarian reserve may demonstrate a decrease in day 3 serum inhibin B before a rise in day 3 follicle-stimulating hormone. Fertil Steril. 1999;72:63–65. doi: 10.1016/S0015-0282(99)00193-4.
    1. Hughes EG, Robertson DM, Handelsman DJ, Hayward S, Healy DL, de Kretser DM. Inhibin and estradiol responses to ovarian hyperstimulation: effects of age and predictive value for in vitro fertilization outcome. J Clin Endocrinol Metab. 1990;70:358–364. doi: 10.1210/jcem-70-2-358.
    1. Hehenkamp WJ, Looman CW, Themmen AP, de Jong FH, Te Velde ER, Broekmans FJ. Anti-Müllerian hormone levels in the spontaneous menstrual cycle do not show substantial fluctuation. J Clin Endocrinol Metab. 2006;91:4057–4063. doi: 10.1210/jc.2006-0331.
    1. Scheffer GJ, Broekmans FJ, Dorland M, Habbema JD, Looman CW, te Velde ER. Antral follicle counts by transvaginal ultrasonography are related to age in women with proven natural fertility. Fertil Steril. 1999;72:845–851. doi: 10.1016/S0015-0282(99)00396-9.
    1. Weenen C, Laven JS, Von Bergh AR, Cranfield M, Groome NP, Visser JA, Kramer P, Fauser BC, Themmen AP. Anti-Müllerian hormone expression pattern in the human ovary: potential implications for initial and cyclic follicle recruitment. Mol Hum Reprod. 2004;10:77–83. doi: 10.1093/molehr/gah015.
    1. Nelson SM, Yates RW, Fleming R. Serum anti-Müllerian hormone and FSH: prediction of live birth and extremes of response in stimulated cycles-implications for individualization of therapy. Hum Reprod. 2007;22:2414–2421. doi: 10.1093/humrep/dem204.
    1. Tsepelidis S, Devreker F, Demeestere I, Flahaut A, Gervy Ch, Englert Y. Stable serum levels of anti-Müllerian hormone during the menstrual cycle: a prospective study in normo-ovulatory women. Hum Reprod. 2007;22:1837–1840. doi: 10.1093/humrep/dem101.
    1. van Disseldorp J, Lambalk CB, Kwee J. et al.Comparison of inter-and intra-cycle variability of anti-Mullerian hormone and antral follicle counts. Hum Reprod. 2010;25:221–227. doi: 10.1093/humrep/dep366.
    1. Lee T, Liu HC, Huang CC, Hsieh KC, Lin PL, Lee MS. Impact of female age and male infertility on ovarian reserve markers to predict outcome of assisted reproduction technology cycles. Reprod Biol Endocrinol Online. 2009;7:100. doi: 10.1186/1477-7827-7-100.
    1. La Marca A, Sighinolfi G, Radi D, Argento C, Baraldi E, Artenisio AC, Stabile G, Volpe A. Anti-Mullerian hormone (AMH) as a predictive marker in assisted reproductive technology (ART) Hum Reprod Update. 2010;16:113–130. doi: 10.1093/humupd/dmp036.
    1. Eldar-Geva T, Ben-Chetrit A, Spitz IM, Rabinowitz R, Markowitz E, Mimoni T, Gal M, Zylber-Haran E, Margalioth EJ. Dynamic assays of inhibin B, anti-Mullerian hormone and estradiol following FSH stimulation and ovarian ultrasonography as predictors of IVF outcome. Hum Reprod. 2005;20:3178–3183. doi: 10.1093/humrep/dei203.
    1. Tremellen KP, Kolo M, Gilmore A, Lekamge DN. Anti-mullerian hormone as a marker of ovarian reserve. Aust N Z J Obstet Gynaecol. 2005;45:20–24. doi: 10.1111/j.1479-828X.2005.00332.x.
    1. Nakhuda GS, Chu MC, Wang JG, Sauer MV, Lobo RA. Elevated serum mullerian-inhibiting substance may be a marker for ovarian hyperstimulation syndrome in normal women undergoing in vitro fertilization. Fertil Steril. 2006;85:1541–1543. doi: 10.1016/j.fertnstert.2005.10.052.
    1. La Marca A, Giulini S, Tirelli A, Bertucci E, Marsella T, Xella S, Volpe A. Anti-Mullerian hormone measurement on any day of the menstrual cycle strongly predicts ovarian response in assisted reproductive technology. Hum Reprod. 2007;22:766–771.
    1. Lee TH, Liu CH, Huang CC, Wu YL, Shih YT, Ho HN, Yang YS, Lee MS. Serum anti-Mullerian hormone and estradiol levels as predictors of ovarian hyperstimulation syndrome in assisted reproduction technology cycles. Hum Reprod. 2008;23:160–167.
    1. Nardo LG, Gelbaya TA, Wilkinson H, Roberts SA, Yates A, Pemberton P, Laing I. Circulating basal anti-Mullerian hormone levels as predictor of ovarian response in women undergoing ovarian stimulation for in vitro fertilization. Fertil Steril. 2008. in press .
    1. Broer SL, Dólleman M, Opmeer BC, Fauser BC, Mol BW, Broekmans FJ. AMH and AFC as predictors of excessive response in controlled ovarian hyperstimulation: a meta-analysis. Hum Reprod Update. 2011;17:46–54. doi: 10.1093/humupd/dmq034.
    1. Nakhuda GS, Douglas NC, Thornton MH, Guarnaccia MM, Lobo R, Sauer MV. Anti-Müllerian hormone testing is useful for individualization of stimulation protocols in oocyte donors. Reprod Biomed Online. 2010;20:42–47. doi: 10.1016/j.rbmo.2009.10.009.
    1. Nelson SM, Yates RW, Lyall H. et al.Anti-Müllerian hormone-based approach to controlled ovarian stimulation for assisted conception. Hum Reprod. 2009;24:867–875.
    1. Gerasimova T, Thanasoula MN, Zattas D, Seli E, Sakkas D, Lalioti MD. Identification and in vitro characterization of follicle stimulating hormone (FSH) receptor variants associated with abnormal ovarian response to FSH. J Clin Endocrinol Metab. 2010;95:529–536. doi: 10.1210/jc.2009-1304.
    1. Greb RR, Grieshaber K, Gromoll J, Sonntag B, Nieschlag E, Kiesel L, Simoni M. A common single nucleotide polymorphism in exon 10 of the human follicle stimulating hormone receptor is a major determinant of length and hormonal dynamics of the menstrual cycle. J Clin Endocrinol Metab. 2005;90:4866–4872. doi: 10.1210/jc.2004-2268.
    1. Liao WX, Goh HH, Roy AC. Functional characterization of a natural variant of luteinizing hormone. Hum Genet. 2002;111:219–224. doi: 10.1007/s00439-002-0781-8.
    1. Huhtaniemi I, Pettersson K. Mutations and polymorphisms in the gonadotrophin genes; clinical relevance. Clin Endocrinol. 1998;48:675–682. doi: 10.1046/j.1365-2265.1998.00454.x.
    1. Jiang M, Pakarinen P, Zhang FP, El-Hefnawy T, Koskimies P, Pettersson K, Huhtaniemi I. A common polymorphic allele of the human luteinizing hormone beta-subunit gene: additional mutations and differential function of the promoter sequence. Hum Mol Genet. 1999;8:2037–2046. doi: 10.1093/hmg/8.11.2037.
    1. Nilsson CH, Kaleva M, Virtanen H, Haavisto AM, Pettersson K, Huhtaniemi IT. Disparate response of wild-type and variant forms of LH to GnRH stimulation in individuals heterozygous for the LHbeta variant allele. Hum Reprod. 2001;16:230–235. doi: 10.1093/humrep/16.2.230.
    1. Alviggi C, Clarizia R, Pettersen K, Mollo A, Humaidan P, Strina I, Coppola M, Ranieri A, D'Uva M, De Placido G. Suboptimal response to GnRHa long protocol is associated with a common LH polymorphism. Reprod Biomed Online. 2009;18:9–14. doi: 10.1016/S1472-6483(10)60418-X.
    1. Gromoll J, Lahrmann L, Godmann M, Muller T, Michel C, Stamm S, Simoni M. Genomic checkpoints for exon 10 usage in the luteinizing hormone receptor type 1 and type 2. Mol Endocrinol. 2007;21:1984–1996. doi: 10.1210/me.2006-0506.
    1. Nordhoff V, Gromoll J, Simoni M. Constitutively active mutations of G protein-coupled receptors: the case of the human luteinizing hormone and follicle-stimulating hormone receptors. Arch Med Res. 1999;30:501–509. doi: 10.1016/S0188-4409(99)00076-4.
    1. Akerman FM, Lei Z, Rao CV, Nakajima ST. A case of spontaneous ovarian hyperstimulation syndrome with a potential mutation in the hCG/LH receptor gene. Fertil Steril. 2000;74:403–404. doi: 10.1016/S0015-0282(00)00628-2.
    1. Hugues JN, Theron-Gerard L, Coussieu C, Pasquier M, Dewailly D, Cedrin-Durnerin. Assessment of theca cell function prior to controlled ovarian stimulation: the predictive value of serum basal/stimulated steroid levels. Hum Reprod. 2010;25:228–234. doi: 10.1093/humrep/dep378.
    1. Revelli A, Delle Piane L, Casano S, Molinari E, Massobrio M, Rinaudo P. Folicular fluid content and oocyte quality: from single biochemical markers to metabolomics. Reprod Biol Endocrinol. 2009;7:40. doi: 10.1186/1477-7827-7-40.
    1. Haouzi D, Mahmoud K, Fourar M, Bendhaou K, Dechaud H, De Vos J, Rème T, Dewailly D, Hamamah S. Identification of new biomarkers of human endometrial receptivity in the natural cycle. Hum Reprod. 2009;24:198–205.

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