Abstract. Introduction

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1 doi: /jog J. Obstet. Gynaecol. Res. Vol. 44, No. 5: , May 2018 Infertility treatment strategy involving combined freeze-all embryos and single vitrified-warmed embryo transfer during hormonal replacement cycle for in vitro fertilization of women with hypogonadotropic Keiji Kuroda 1, Kenji Ezoe 2, Keiichi Kato 2, Akiko Yabuuchi 2, Tomoya Segawa 3, Tamotsu Kobayashi 2, Asako Ochiai 1, Noriko Katoh 1 and Satoru Takeda 1 1 Department of Obstetrics & Gynaecology, Juntendo University, 2 Kato Ladies Clinic and 3 Shinbashi Yume Clinic, Tokyo, Japan Abstract Aim: Hypogonadotropic (HH) is a condition caused by the deficient secretion of pituitary gonadotropins, leading to diminished ovarian function. Several studies of in vitro fertilization (IVF) in women with HH revealed acceptable clinical pregnancy outcomes but high multiple pregnancy rates after multiple fresh embryo transfer (ET). The purpose of this study was to analyze the outcomes of combined freeze-all embryos and single vitrified-warmed ET in women with HH. Methods: Of 91 infertile women with HH (basal luteinizing hormone and follicle-stimulating hormone levels <2.0 miu/ml), we excluded patients aged 40 years (n = 2) and women who preferred fresh ET (n = 10). Seventy-nine women underwent 117 oocyte retrieval cycles and 135 vitrified-warmed ET during hormone replacement (HR) cycles from 2008 to 2014 at the Kato Ladies Clinic and Juntendo University Hospital. Results: In 26 single cleavage ET cycles, the rates of clinical pregnancy and live birth were 34.6% (9/26 ET) and 26.9% (7/26 ET), respectively. Regarding the outcomes after single vitrified-warmed blastocyst transfer, clinical pregnancy and live birth rates were 65.1% (71/109 ET) and 50.5% (55/109 ET), respectively. Multiple conceptions and ovarian hyperstimulation syndrome did not occur in any of the women with HH. Conclusion: Our results demonstrated that IVF followed by single vitrified-warmed ET in adjusted endocrine milieu during the HR cycle is an effective fertility treatment for women with HH and decreases the incidence of complications, including multiple conceptions. Key words: elective single embryo transfer, embryo vitrification, hormone replacement therapy, hypogonadotropic, in vitro fertilization. Introduction Decreased synthesis or secretion of pituitary gonadotropins results in impaired gonadal function, which is a condition known as hypogonadotropic (HH). 1 3 HH is caused by deficiencies in hypothalamic endogenous gonadotropin-releasing hormone (GnRH) release or pituitary gonadotropin secretion, leading to an imbalance in the hypothalamic pituitary gonadal (HPG) axis and diminished ovarian function. Therefore, women with HH show symptoms of hypoestrogenism, ovulation disorders and amenorrhea. However, according to the data of an ovarian function biomarker, anti-müllerian hormone, most women with HH have age-dependent ovarian reserve. 4 Therefore, optimal induction of gonadotropin Received: September Accepted: December Correspondence: Dr Keiichi Kato, Kato Ladies Clinic, Nishishinjuku, Shinjuku-ku, Tokyo , Japan. k-kato@towako. net; Dr Keiji Kuroda, Department of Obstetrics and Gynecology, Juntendo University, Faculty of Medicine, Hongo, Bunkyo-ku, Tokyo , Japan. arthur@juntendo.ac.jp Japan Society of Obstetrics and Gynecology

2 IVF for hypogonadotropic secretion by pulsatile GnRH or continuous gonadotropin administration may improve folliculogenesis and ovulation, leading to improving pregnancy rates theoretically. 5 7 Pulsatile GnRH therapy can be used to recover the periodic gonadotropin secretion; however, some patients suffer from the use of the portable pump for injection of GnRH for several weeks, and it is ineffective therapy for primary pituitary failure. 8 In general, to promote follicular growth and maturation, exogenous gonadotropins, such as human menopausal gonadotropin (hmg) or a combination of recombinant luteinizing hormone (LH) and follicle-stimulating (FSH), are administered followed by an injection of human chorionic gonadotropin (hcg) The conventional ovulation induction procedure for patients with HH is daily low-dose injections of gonadotropins with the aim of producing a few follicles without complications, such as multiple conceptions and ovarian hyperstimulation syndrome (OHSS). 8,11 However, mild ovarian stimulation often fails to induce follicle development because the parameters necessary to predict the threshold for ovarian response are not available in patients with HH. Therefore, it is difficult to find an individual optimal ovarian stimulation with daily gonadotropin injection in infertile women with HH. Assisted reproductive technology, including in vitro fertilization (IVF), has developed in recent years. In particular, the advantages of vitrification methods have allowed a high survival rate of embryos after warming, in addition to pregnancy outcomes comparable to those of fresh embryos. 12 Several studies have reported the pregnancy outcomes after IVF in women with HH. 9,13,14 However, in these studies, multiple fresh embryo transfer (ET) was mainly performed in the oocyte retrieval cycles. These studies demonstrated that multiple fresh ET in patients with HH produced acceptable clinical pregnancy outcomes with a high multiple pregnancy rate. 13,14 The freezeall policy followed by single frozen-warmed ET has increasingly been used as the IVF treatment strategy with low incidence of complications, including multiple conceptions and OHSS. This strategy can avoid the need for ET under nonphysiological conditions. 12,15,16 Furthermore, this strategy allows for ET to be performed later in a cycle along with hormone replacement (HR), which addresses luteal hypofunction in women with HH. Therefore, we hypothesized that combined treatment with freeze-all embryos and single vitrified-warmed ET during the HR cycle may be physiological and beneficial as an IVF strategy for women with HH, yet the reports on the pregnancy Figure 1 Flow diagram of patients included in the study. Of 91 consecutive infertile women with hypogonadotropic, we excluded patients aged 40 years (n = 2) and women who preferred fresh embryo transfer (ET) (n = 10) and recruited 117 oocyte retrieval cycles in 79 patients. In two cycles, no competent embryo for freezing was obtained after oocyte retrieval and IVF, and we classified 137 ET cycles 77 patients into 26 cleavage ET cycles and 111 blastocyst transfer cycles. outcomes after single vitrified-warmed ET in women with HH are limited. The aim of this study was to retrospectively analyze the clinical outcomes of women with HH who underwent IVF and subsequent single vitrified-warmed ET during the HR cycle. Methods Patients This study was approved by the institutional review boards of Kato Ladies Clinic (approval number: 16-13) and Juntendo University Hospital (approval number: ). Ninety-one consecutive infertile women with HH underwent oocyte retrieval from January 2008 to December 2014 at Kato Ladies Clinic and Juntendo University Hospital. The diagnosis of HH was based on primary or secondary amenorrhea with extremely low basal gonadotropin levels: basal LH and FSH levels <2.0 miu/ml. We planned oocyte retrieval after ovarian stimulation, cryopreservation of all embryos and single vitrified-warmed ET during the HR cycle. We excluded patients aged 40 years (n = 2) and women who preferred fresh ET (n = 10) and recruited 117 oocyte retrieval cycles and 137 ET cycles in 79 patients (Fig. 1). The follow-up data of the pregnancy outcomes of all patients were available. No woman had conceived previously or had experienced a serious medical disorder. Written informed 2018 Japan Society of Obstetrics and Gynecology 923

3 K. Kuroda et al. consent was obtained from all women undergoing IVF treatment at the centers after they were informed that their deidentified data could be used for a retrospective study. Controlled ovarian stimulation All women were monitored using ultrasonography and serum hormone levels at day 3 of menstruation and received IU of hmg (Ferring Pharmaceuticals, Saint Prex, Switzerland, or Kowa Pharmaceuticals, Aichi, Japan) daily. In all cycles, we confirmed developed follicles and administered 5000 IU of hcg (Mochida Pharmaceutical, Tokyo, Japan, or ASKA Pharmaceutical, Tokyo, Japan) by intramuscular injection. The initial dose use of hmg was IU daily and was adjusted based on the individual patient s ovarian response. Oocyte retrieval was usually performed tranvaginally h after hcg injection. Insemination and embryo culture Conventional IVF or intracytoplasmic sperm injection (ICSI) was performed approximately 3 or 5 h after oocyte retrieval, respectively. 17 HTF medium (Kitazato corporation, Shizuoka, Japan) supplemented with 10% serum substitute supplement (Irvine Scientific, CA, USA) was used as the fertilization medium. Fertilization assessment was performed h after conventional IVF or ICSI (day 1). Typically, fertilized zygotes were cultured individually in 20 μl of Quinn Advantage Protein Plus cleavage medium (Origio, Målov, Denmark) on days 1 3. Following this, most of embryos were transferred to Quinn Advantage Protein Plus blastocyst medium (Origio) on days 4 6. All embryos were cultured at 37 C under 5% O 2,5%CO 2 and 90% N 2 with 100% humidity in water jacket incubators or nonhumidified incubators (Astec Co. Ltd., Fukuoka, Japan). Vitrification and ET All embryos were cultured to the cleavage embryo or blastocyst stages. We excluded the cleavage embryos of Veeck classification Grade 5, two to three cell embryos at 2 days and two to four cell embryos at 3 days after fertilization, and the blastocysts of Gardner classification Grade 1 3 at 7 days after fertilization. Selected morphologically and developmentally competent embryos were vitrified for subsequent use in ET cycles. The Cryotop method of vitrification (Kitazato Corporation, Shizuoka, Japan) was used, as described previously. 17,18 In the HR cycle, the administration of estradiol (Hisamitsu Pharmaceutical Co., Inc., Tokyo, Japan, or Bayer AG., Leverkusen, Germany) was started from day 2 or 3 of the cycle. Dydrogesterone (30 mg/day, Daiichi Sankyo Company, Limited, Tokyo, Japan) was added from day 11 of the cycle; blastocysts were transferred 5 7 days later. Dydrogesterone was routinely administered orally during the early luteal phase after the vitrifiedwarmed ET procedures. In addition, intramuscular (ASKA Pharmaceutical. Co., Ltd.) or intravaginal progesterone (Ferring Pharmaceuticals) was administered until the 8th to 9th week of pregnancy. Data analysis All analyses were conducted using JMP (SAS, NC, USA). The cumulative live birth rates were calculated by two approaches. The first method is referred to as crude live birth rate, which calculates the outcome by dividing the number of women achieving live birth after a predetermined number of cycles by the total number of women who were scheduled for oocyte retrieval. The second method is referred to as expected live birth rate, which estimates the cumulative live birth rate by taking into account the effect of censoring (Kaplan Meier method). Results Baseline patient characteristics The demographic characteristics of the 79 women with HH are shown in Table 1. The frequency of causes of HH included the following rates: 5.1% for pituitary tumor or surgery for pituitary tumor, 39.2% for reduction of body weight and 55.7% for unexplained. The average patient age and body mass index were years and kg/m 2, respectively. The basal serum levels of estradiol FSH,and and LH prolactin were pg./ml, miu/ml, miu/ml, and pg./ml, respectively. IVF outcomes The outcomes of 117 IVF/ICSI cycles in 79 women are shown in Table 2. The mean duration of ovarian stimulation was days, and the total amount of gonadotropin injected and the serum level of estradiol on the day of hcg injection were IU and pg./ml, respectively. The mean numbers of retrieved oocytes, fertilized oocytes and cleaved embryos per oocyte retrieval Japan Society of Obstetrics and Gynecology

4 IVF for hypogonadotropic Table 1 Characteristics of infertile women with hypogonadotropic No. of patients with 79 hypogonadotropic Causes of hypogonadotropic Pituitary tumor or surgery 4 (5.1) for pituitary tumor Reduction of body weight 31 (39.2) Unknown 44 (55.7) Menstruation Primary amenorrhea 5 (6.3) Secondary amenorrhea 74 (93.7) Age (years) (25 39) BMI (kg/m 2 ) ( ) Size of ovaries (major axis, cm) ( ) Basal serum hormonal level Estradiol (pg/ml) (0 81) FSH (miu/ml) (0 1.9) LH (miu/ml) (0 1.8) Prolactin (ng/ml) ( ) TSH (μiu/ml) ( ) Other infertility factors Fallopian tubal factor 8 (10.1) Male factor 2 (2.5) Size of ovaries is average of both ovaries. Number of patients who measured serum TSH level was 28. Data are expressed as means SEM (range) or n (%). BMI, body mass index; FSH, follicle-stimulating hormone; LH, luteinizing hormone; TSH, thyroid-stimulating hormone. cycle were , and , respectively. Fertilization rates after conventional IVF and ICSI were 69.8% and 83.8%, respectively. Blastocyst development ratio after conventional IVF and ICSI were 57.1% and 48.9%, respectively. Finally, the mean number of cryopreserved cleavage embryos or blastocysts, which were categorized as morphologically and developmentally competent embryos, was In two cycles, no competent embryo for freezing was obtained after oocyte retrieval and IVF (Fig. 1). Pregnancy outcomes after single vitrified-warmed blastocyst transfer The outcomes of the 135 single ET cycles in 77 women are shown in Table 3. The rates of clinical pregnancy and live birth in 26 single cleavage ET cycles were 34.6% (9/26 ET) and 26.9% (7/26 ET), respectively. The outcomes of single vitrified-warmed blastocyst transfer showed that clinical pregnancy and live birth rates were 65.1% (71/109 ET) and 50.5% (55/109 ET), respectively. The clinical miscarriage rates per Table 2 In vitro fertilization outcomes in infertile women with hypogonadotropic No. of oocyte retrieval cycles 117 Duration of stimulation (d) (4 24) Total amount of gonadotropin injected (IU) ( ) Estradiol at the time of hcg injection (pg/ml) ( ) No. of oocytes retrieved (/cycle, n) (1 42) No. of oocytes that matured (/cycle, n) (0 40) No. of cycles inseminated 113 Conventional IVF 39 (34.5) ICSI 37 (32.7) Both conventional IVF and ICSI 37 (32.7) No. of fertilized oocytes (/cycle, n) (0 33) Fertilization ratio (/ oocytes, %) Conventional IVF 69.8 ICSI 83.8 No. of cleaved embryos (/cycle, n) (0 32) Cleavage ratio (/2-pronuclei embryos, %) Conventional IVF 89.6 ICSI 90.7 Blastocyst development ratio (/2-pronuclei embryos, %) Conventional IVF 57.1 ICSI 48.9 No. of embryos cryopreserved (/cycle, n) (0 16) Data are expressed as means SEM (range) or n (%). hcg, human chorionic gonadotropin; ICSI, intracytoplasmic sperm injection; IVF, in vitro fertilization. pregnancy were 22.2% (2/9 pregnancies) in cleavage ET cycles and 22.5% (16/71 pregnancies) in blastocyst transfer cycles. Multiple conceptions and OHSS did not occur in any of the women with HH in the present study. When women with HH produced morphologically and developmentally competent blastocysts, more than half of them successfully delivered babies after single vitrified-warmed blastocyst transfer during HR cycles. We also analyzed the crude and expected cumulative live birth rates with 95% confidence intervals (CI) after the single vitrified-warmedetprocedures (Table 4). The crude cumulative live birth rate at the first oocyte retrieval was 55.7% (CI: ), and the rate at the third oocyte retrieval was 73.4% (CI: ). Finally, the expected cumulative live birth at the third oocyte retrieval was 83.1% (CI: ) Japan Society of Obstetrics and Gynecology 925

5 K. Kuroda et al. Table 3 Pregnancy outcomes in infertile women with hypogonadotropic Cleavage embryo Blastocyst Total No. of embryo transfer cycles Clinical pregnancy (/embryo transfer) 9 (34.6) 71 (65.1) 80 (59.3) Ongoing pregnancy (/embryo transfer) 9 (34.6) 63 (57.8) 72 (53.3) Live birth (/embryo transfer) 7 (26.9) 55 (50.5) 62 (45.9) Miscarriage (/pregnancy) 2 (22.2) 16 (22.5) 18 (22.5) Multiple pregnancy (/embryo transfer) 0 (0) 0 (0) 0 (0) Data are expressed as n (%). Table 4 Cumulative live birth rate after single vitrified-warmed blastocyst transfer in women with hypogonadotropic Treatment cycle number Crude cumulative live birth rate (%) Low 95% CI (%) High 95% CI (%) Expected cumulative live birth rate (%) Low 95% CI (%) High 95% CI (%) Expected cumulative live birth rate was estimated by taking into account the effect of censoring (Kaplan Meier method). CI, confidence interval. Discussion Women with HH have abnormalities in the HPG axis and ovarian function but have age-dependent dormant follicles in their ovaries. 4,19 Theoretically, optimal physiological activation of ovarian follicles via gonadotropin administration can induce the development of single follicles and prevent multiple pregnancies and OHSS. Yet, it is difficult to implement a protocol personalized to the ovarian response of patients with HH. In this study, approximately 10 oocytes were retrieved after the injection of hmg and hcg (Table 2). An average of 3.9 embryos of morphologically and developmentally competent quality were cryopreserved after IVF/ICSI, meaning that single oocyte retrieval yields nearly four attempts of single vitrified-warmed ET in a subsequent HR cycle (Table 2). The present study showed that the rates of clinical pregnancy and live birth were 59.3% and 45.9%, respectively. The cumulative live birth rate at the first oocyte retrieval was 55.7%, and the live birth rate was expected to be >80% after the third oocyte retrieval (Tables 3 and 4). Multiple fresh ET were chosen as the main strategy for women with HH in previous studies. 9,13,14 Ulug et al. reported that the clinical pregnancy and multiple pregnancy rates were 56.6% (30/53 ET cycles) and 46.6% (14/30 pregnancies), respectively, in 58 women with HH after multiple fresh ET (average number of transferred embryos: ). 14 Recently, a clinical pregnancy rate of 19.4% (14/72 ET cycles) and live birth rate of 15.2% (11/72 ET cycles) with a multiple conception rate of 28.5% (4/14 pregnancies) in 81 women with HH were reported. 13 Ovarian stimulation associated with supraphysiological levels of steroid hormones can disturb optimal uterine receptivity and embryo implantation by perturbation of embryo-endometrial synchrony It is possible that the endometrial condition was not optimal for implantation in women with HH after ovarian stimulation with exogenous gonadotropins, and ET with multiple fresh embryos demonstrated relatively low OHSS and miscarriage rates but a high multiple pregnancy rate. 13,14 Most patients with HH have impaired uterine development after long-term amenorrhea. 28 Those patients may have higher risks of multiple pregnancy, including preterm labor and premature infant, compared to those of women with a normal uterus. Single vitrified-warmed ET during the cycles following egg retrieval with HR treatment may optimize synchronization of the interaction between a receptive endometrium and a high-quality embryo with minimization of the adverse effects of ovarian stimulation, leading to improved pregnancy outcomes without risk of multiple conceptions in women with HH Japan Society of Obstetrics and Gynecology

6 IVF for hypogonadotropic One limitation of this study was that we did not compare pregnancy outcomes between women with HH who underwent single vitrified-warmed ET and those who underwent fresh ET. Further studies are required to compare and analyze pregnancy outcomes after different ET methods. Conclusion In conclusion, the results of the present study demonstrated that IVF followed by single vitrified-warmed ET in adjusted endocrine milieu during the HR cycle is an effective fertility treatment for women with HH and improves the live birth rate and decreases the incidence of complications, including multiple conceptions. Acknowledgments The authors thank all the patients who participated in this study. Disclosure None declared. References 1. Silveira LFG, MacColl GS, Bouloux PMG. Hypogonadotropic. Semin Reprod Med 2002; 20: Reame NE, Sauder SE, Case GD, Kelch RP, Marshall JC. Pulsatile gonadotropin secretion in women with hypothalamic amenorrhea: Evidence that reduced frequency of gonadotropin-releasing hormone secretion is the mechanism of persistent anovulation. J Clin Endocrinol Metab 1985; 61: Perkins RB, Hall JE, Martin KA. Neuroendocrine abnormalities in hypothalamic amenorrhea: Spectrum, stability, and response to neurotransmitter modulation. J Clin Endocrinol Metab 1999; 84: Sonmezer M, Ozmen B, Atabekoglu CS et al. Serum anti- Müllerian hormone levels correlate with ovarian response in idiopathic hypogonadotropic. J Assist Reprod Genet 2012; 29: Sungurtekin U, Fraser IS, Shearman RP. Pregnancy in women with Kallmann s syndrome. Fertil Steril 1995; 63: Spitz IM, Rosen E, Ben-Aderet N, Polishuk W, Jaffe H, Bercovici B. Isolated hypogonadotropic : Induction of ovulation with exogenous gonadotropins. Fertil Steril 1977; 28: Shoham Z, Balen A, Patel A, Jacobs HS. Results of ovulation induction using human menopausal gonadotropin or purified follicle-stimulating hormone in hypogonadotropic patients. Fertil Steril 1991; 56: Group TECW. Anovulatory infertility. Hum Reprod 1995; 10: Yildirim G, Ficicioglu C, Attar R, Akcin O, Tecellioglu N. Comparision of reproductive outcome of the women with hypogonadotropic and tubal factor infertility. Clin Exp Obstet Gynecol 2010; 37: Hillier SG. Gonadotropic control of ovarian follicular growth and development. Mol Cell Endocrinol 2001; 179: Group TERHLS. Recombinant human luteinizing hormone (LH) to support recombinant human follicle-stimulating hormone (FSH)-induced follicular development in LH- and FSH-deficient anovulatory women: A dose-finding study. J Clin Endocrinol Metab 1998; 83: Kato K, Takehara Y, Segawa T et al. Minimal ovarian stimulation combined with elective single embryo transfer policy: Age-specific results of a large, single-centre, Japanese cohort. Reprod Biol Endocrinol 2012; 10: Ghaffari F, Arabipoor A, Lankarani NB, Etminan Z, Tehraninejad ES. Assisted reproductive technique outcomes in hypogonadotropic women. Ann Saudi Med 2013; 33: Ulug U, Ben-Shlomo I, Tosun S, Erden HF, Akman MA, Bahceci M. The reproductive performance of women with hypogonadotropic in an in vitro fertilization and embryo transfer program. J Assist Reprod Genet 2005; 22: Maheshwari A, Griffiths S, Bhattacharya S. Global variations in the uptake of single embryo transfer. Hum Reprod Update 2011; 17: Roque M, Valle M, Guimaraes F, Sampaio M, Geber S. Freeze-all policy: Fresh vs. frozen-thawed embryo transfer. Fertil Steril 2015; 103: Kato K, Ueno S, Yabuuchi A et al. Women s age and embryo developmental speed accurately predict clinical pregnancy after single vitrified-warmed blastocyst transfer. Reprod Biomed Online 2014; 29: Mori C, Yabuuchi A, Ezoe K et al. Hydroxypropyl cellulose as an option for supplementation of cryoprotectant solutions for embryo vitrification in human assisted reproductive technologies. Reprod Biomed Online 2015; 30: Chan C, Liu K. Clinical pregnancy in a woman with idiopathic hypogonadotropic and low AMH: Utility of ovarian reserve markers in IHH. J Assist Reprod Genet 2014; 31: Ubaldi F, Bourgain C, Tournaye H, Smitz J, Van Steirteghem A, Devroey P. Endometrial evaluation by aspiration biopsy on the day of oocyte retrieval in the embryo transfer cycles in patients with serum progesterone rise during the follicular phase. Fertil Steril 1997; 67: Kolibianakis E, Bourgain C, Albano C et al. Effect of ovarian stimulation with recombinant follicle-stimulating hormone, gonadotropin releasing hormone antagonists, and human chorionic gonadotropin on endometrial maturation on the day of oocyte pick-up. Fertil Steril 2002; 78: Van Vaerenbergh I, Van Lommel L, Ghislain V et al. In GnRH antagonist/rec-fsh stimulated cycles, advanced endometrial maturation on the day of oocyte retrieval correlates with altered gene expression. Hum Reprod 2009; 24: Japan Society of Obstetrics and Gynecology 927

7 K. Kuroda et al. 23. Ezoe K, Daikoku T, Yabuuchi A et al. Ovarian stimulation using human chorionic gonadotrophin impairs blastocyst implantation and decidualization by altering ovarian hormone levels and downstream signaling in mice. Mol Hum Reprod 2014; 20: Horcajadas JA, Pellicer A, Simon C. Wide genomic analysis of human endometrial receptivity: New times, new opportunities. Hum Reprod Update 2007; 13: Bourgain C, Devroey P. The endometrium in stimulated cycles for IVF. Hum Reprod Update 2003; 9: Bourgain C, Ubaldi F, Tavaniotou A, Smitz J, Van Steirteghem AC, Devroey P. Endometrial hormone receptors and proliferation index in the periovulatory phase of stimulated embryo transfer cycles in comparison with natural cycles and relation to clinical pregnancy outcome. Fertil Steril 2002; 78: Teh WT, McBain J, Rogers P. What is the contribution of embryo-endometrial asynchrony to implantation failure? J Assist Reprod Genet 2016; 33: Boehm U, Bouloux PM, Dattani MT et al. Expertconsensus document: European consensus statement on congenital hypogonadotropic --pathogenesis, diagnosis and treatment. Nat Rev Endocrinol 2015; 11: Japan Society of Obstetrics and Gynecology