Asimina Tavaniotou

Impact of ovarian stimulation on corpus luteum function and embryonic implantation.

The luteal phase has been found to be defective in virtually all the stimulation protocols used in in-vitro fertilization (IVF), indicating that common mechanisms might be involved despite the use of different drugs. A normal luteal phase is characterised by a normal hormonal environment, normal progesterone secretion by the corpus luteum and adequate endometrial secretory transformation. Luteinizing hormone supports the corpus luteum and luteal luteinizing hormone (LH) levels have been found to be reduced in human menopausal gonadotrophin (HMG), gonadotrophin-releasing hormone (GnRH)-agonist/HMG and GnRH-antagonist/HMG protocols, probably leading to an insufficient corpus luteum function. Supraphysiological steroid serum concentrations routinely observed in stimulated cycles may adversely affect LH secretion and induce a luteal-phase defect. In turn, these high steroid serum concentrations may advance early luteal-phase endometrial development leading to embryo-endometrial asynchrony and decreased pregnancy rates in IVF cycles.

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

OBJECTIVE To investigate the endometrial steroid receptors and proliferation index in GnRH analogue/hMG-stimulated cycles in comparison with natural cycles and their relation to clinical pregnancy outcome. DESIGN Prospective observational study. SETTING Tertiary referral center. PATIENT(S) Twenty-seven stimulated patients with GnRH agonist and hMG. Twenty normo-ovulatory patients were the natural cycle controls. INTERVENTION(S) Endometrial aspiration biopsies: in stimulated cycles on the day of oocyte retrieval within the ET cycle (Day OPU) (n = 20) or 2 days later (Day OPU + 2) (n = 7); in natural cycles on the natural day of ovulation (Day NO) (n = 10) or on the day of ovulation + 2 (Day NO + 2) (n = 10). MAIN OUTCOME MEASURE(S) Comparison of endometrial maturation, estrogen (ER) and P receptor (PR), and proliferation index by immunohistochemistry in natural and stimulated cycles, correlation with pregnancy outcome in stimulated cycles. RESULT(S) Stimulated cycles Day OPU showed significantly advanced endometrial maturation compared to natural cycles Day NO; stromal ER and glandular and stromal PR staining was lower in stimulated than in natural cycles, but higher on Day OPU than on Day NO + 2; proliferation index was lower in all stimulated cycles. Steroid receptors and proliferation index in stimulated cycles were unrelated to clinical pregnancy occurrence. CONCLUSION(S) Compared to natural cycles, ovarian stimulation induced an imbalance in endometrial ER and PR and led to a profound antimitotic effect in the peri-ovulatory phase. These parameters were, however, not predictive of clinical pregnancy in cycles with ET.

Ovulation induction disrupts luteal phase function.

Abnormalities in the luteal phase have been detected in virtually all the stimulation protocols used in in vitro fertilization, on both the hormonal and endometrial levels. Supraphysiological follicular or luteal sex steroid serum concentrations, altered estradiol: progesterone (E2/P) ratio, and disturbed luteinizing hormone pituitary secretion leading to corpus luteum insufficiency or a direct drug effect have been postulated as the main etiologic factors. Luteinizing hormone supports corpus luteum function, and low LH levels have been described after human menopausal gonadotropin treatment, after gonadotropin‐releasing hormone (GnRH)‐agonist treatment, or after GnRH‐antagonist treatment. These low luteal LH levels may lead to an insufficient corpus luteum function and consequently to a shortened luteal phase or to the low luteal progesterone concentrations frequently described after ovulation induction. A direct effect of the GnRH agonist or GnRH antagonist on human corpus luteum or on human endometrium and thus on endometrial receptivity cannot be excluded, as GnRH receptors have been described in both compartments. Endometrial histology has revealed a wide range of abnormalities during the various stimulation protocols. In GnRH‐agonist cycles, mid‐luteal biopsies have revealed increased glandulo‐stromal dyssynchrony and delay in endometrial development, strong positivity of endometrial glands for progesterone receptors, decreased αvβ3‐integrin subunit expression, and earlier appearance of surface epithelium pinopodes. These factors suggest a shift forwards of the implantation window. Progesterone supplementation improves endometrial histology, and its necessity has been well established, at least in cycles using GnRH agonists.

Effect of clomiphene citrate on follicular and luteal phase luteinizing hormone concentrations in in vitro fertilization cycles stimulated with gonadotropins and gonadotropin-releasing hormone antagonist

OBJECTIVE To investigate the effect that clomiphene citrate exerts on luteinizing hormone (LH) concentrations in gonadotropin/gonadotropin-releasing hormone (GnRH) antagonist cycles. DESIGN Retrospective analysis. SETTING Tertiary referral center. PATIENT(S) Two groups of patients undergoing in vitro fertilization (IVF) were compared. In group I, 20 patients were stimulated with clomiphene citrate (CC) in combination with gonadotropins and 0.25 mg of Cetrorelix (ASTA Medica AG; Frankfurt am Main, Germany) and in group II, 20 patients were stimulated with gonadotropins and 0.25 mg of Cetrorelix. INTERVENTION(S) Blood sampling was performed in the late follicular, periovulatory, early, mid, and late luteal phases. MAIN OUTCOME MEASURE(S) Luteinizing hormone (LH), estradiol, and progesterone. RESULT(S) LH levels were significantly higher in group I than in group II on all the days studied. Progesterone serum concentrations were significantly higher in group II in the early luteal phase, but not in the follicular or the middle and late luteal phases. CONCLUSION(S) LH concentrations are significantly higher in the follicular and luteal phases in cycles stimulated with CC, despite GnRH antagonist administration. This observation might have implications for the dose of GnRH antagonist needed to suppress LH in the follicular phase and questions the need for luteal-phase supplementation in cycles in which CC was used.

Luteal hormonal profile of oocyte donors stimulated with a GnRH antagonist compared with natural cycles

The effect of gonadotrophin-releasing hormone (GnRH) antagonist treatment on luteal phase hormonal profile has not yet been fully investigated. Cycle characteristics of 23 fertile donors stimulated with recombinant FSH and the GnRH antagonist, ganirelix 0.25, for IVF and receiving no kind of luteal supplementation were compared with control, natural cycles. Luteal luteinizing hormone (LH) serum concentrations as well area under the curve (AUC) for LH were significantly higher in natural cycles. In addition, luteal phase length was longer in natural cycles compared with donor cycles. Luteinizing hormone values dropped in the luteal phase of the stimulated cycles, with the lowest values being observed in the mid-luteal phase. AUC for progesterone in the luteal phase was significantly higher in the stimulated cycles compared with natural cycles (P < 0.001). Low LH serum concentrations and shortened luteal phase indicate the need for luteal phase supplementation in GnRH antagonist IVF cycles.

GnRH antagonists and endometrial receptivity in oocyte recipients: a prospective randomized trial

The effect that gonadotrophin-releasing hormone (GnRH) antagonists exert on endometrial receptivity has not yet been elucidated. GnRH antagonists might directly affect oocytes, the embryo and/or the endometrium. The aim of this study was to investigate the direct effect of GnRH antagonists on the endometrium in oocyte donation cycles. In an oocyte donation programme, oocytes from each donor (n = 49), stimulated with gonadotrophins and a GnRH antagonist, were equally shared between two different matched recipients. Recipients were randomly allocated to either receive a GnRH antagonist concomitant to donor during their endometrial priming with oestradiol (group I, n = 49) or to solely continue with their endometrial preparation (group II, n = 49). Pregnancy rate was 55.1% in group I and 59.1% in group II. Implantation rate was 26.1% in group I and 24.4% in group II. Endometrial thickness was also similar between the two groups on the day of human chorionic gonadotrophin injection to the donor. In conclusion, GnRH antagonist administration during the proliferative phase at a dose of 0.25 mg per day does not appear to adversely affect endometrial receptivity in oocyte recipients.

Endometrial integrin expression in the early luteal phase in natural and stimulated cycles for in vitro fertilization

OBJECTIVE To investigate the effect of ovarian stimulation on integrin expression in the early luteal phase. STUDY DESIGN Seven endometrial biopsies were taken 2 days after the oocyte retrieval from stimulated cycles for IVF and 23 from natural cycles, 2 days after ovulation. RESULT Endometrium was in-phase in 22/23 and 7/7 biopsies from the natural and stimulated cycles, respectively. Integrins alpha(1) and alpha(4) were simultaneously positive in 43.4% from the natural and in all (100%) the stimulated cycles (P<0.03). On the day of the endometrial biopsy, progesterone serum values were higher in the stimulated cycles (55.2+/-9.5 microg/l versus 8.5+/-3.8 microg/l) (P<0.001). HSCORE value was significantly higher in stimulated cycles for both integrins. CONCLUSION Endometrial integrin expression is more consistently present in the early luteal phase in stimulated cycles than in natural cycles and this may be related to the higher serum progesterone concentration and/or the more advanced endometrial histological features.

The impact of LH serum concentration on the clinical outcome of IVF cycles in patients receiving two regimens of clomiphene citrate/gonadotrophin/0.25 mg cetrorelix

Clomiphene citrate treatment with the association of gonadotrophins and the GnRH antagonist cetrorelix 0.25mg was analysed in two different stimulation protocols for IVF. In protocol I, 18 patients were sequentially stimulated with clomiphene citrate and gonadotrophins. In protocol II, 28 patients started the gonadotrophin injections during the clomiphene citrate administration. LH values significantly dropped after the first 0.25 mg cetrorelix injection in both protocols. A total of 22% and 7% of cycles were cancelled in protocols I and II, respectively, because of poor follicular development. The clinical pregnancy rate following embryo transfer was 18.1% in protocol I and 29.1% in protocol II. In two (11.1%) cycles stimulated according to protocol I and in eight (28.5%) cycles from protocol II, premature LH surges occurred. In patients with premature LH surge, significantly fewer metaphase II oocytes were obtained. The clinical pregnancy rate following embryo transfer was 12.5% in patients with surge compared with 29.6% in patients without. LH values were lower before HCG injection in patients who achieved pregnancy in the study cycle. In conclusion, sequential clomiphene citrate and gonadotrophin administration is not recommended for clomiphene citrate/gonadotrophin/cetrorelix 0.25 cycles. Cetrorelix 0.25 mg/day was associated with a high incidence of premature LH surges and premature LH surges were associated with an adverse cycle outcome.