1 Assisted Conception Unit, Royal Infirmary of Edinburgh, 2 Department of Reproductive and Developmental Sciences and 3 MRC Human Reproductive Sciences Unit, Centre for Reproductive Biology, University of Edinburgh, 49 Little France Crescent, Edinburgh EH16 4SB, UK 4 To whom correspondence should be addressed. e-mail: r.a.anderson{at}hrsu.mrc.ac.uk
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Abstract |
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Key words: FSH/follicular development/inhibin B/ovarian reserve/pituitary down-regulation
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Introduction |
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There is currently much interest in determining the size of the growing follicular pool. This is of particular value in the context of controlled ovarian stimulation (COS) and IVF to identify those women from whom few oocytes will be recovered or conversely are at increased risk of ovarian hyperstimulation syndrome (OHSS) (Gulekli et al., 1999; Bukman and Heineman, 2001
). The serum concentration of FSH during the cycle is regulated by the negative feedback effect of ovarian hormones, i.e. estradiol and the inhibins (Hayes et al., 1998
; Baird, 1999
). FSH concentrations in the early follicular phase show an inverse relationship to the size of the follicular cohort (Chang et al., 1998
). The rise in FSH concentration after clomiphene citrate administration (clomiphene challenge test) has been shown to be of value in unmasking poor responders to COS who would not have been detected by basal FSH alone (Navot et al., 1987
; Tanbo et al., 1989
; Loumaye et al., 1990
; Gulekli et al., 1999
). It might be anticipated that direct hormonal products of the ovary would be better markers of ovarian response than indirect markers such as age and FSH. The rise in estradiol concentrations after FSH (Fanchin et al., 1994
; Phelps et al., 1998
; Syrop et al., 1999
; Fabregues et al., 2000
) or GnRH analogue (Padilla et al., 1990
; Winslow et al., 1991
; Ranieri et al., 1998
; Ravhon et al., 2000
) administration has been shown to be predictive of IVF success, although high basal estradiol concentrations were associated with increased IVF cycle cancellation and lower pregnancy rates (Licciardi et al., 1995
; Smotrich et al., 1995
).
Inhibins are also products of the ovary. Tissue localization studies (Rabinovici et al., 1992; Roberts et al., 1993
; Yamoto et al., 1993
; Jaatinen et al., 1994
) and changes in serum levels of inhibin A and B during the menstrual cycle and in response to gonadotrophin manipulation, suggest that inhibin B is secreted predominantly by smaller antral follicles (Groome et al., 1996
; Welt et al., 1997
; Anderson et al., 1998
; Lahlou et al., 1999
) and inhibin A mainly by the dominant follicle (Groome et al., 1994
; Lambert-Messerlian et al., 1994
). Dynamic inhibin B testing with FSH (Lockwood et al., 1996
; Dzik et al., 2000
) or GnRH analogue (Ravhon et al., 2000
) appears to correlate with ovarian response to COS, but the value of basal inhibin B measured in the early follicular phase remains uncertain (Seifer et al., 1997
; Tinkanen et al., 1999
; Creus et al., 2000
; Dumesic et al., 2001
). Female age was shown to be superior to basal inhibin B at predicting pregnancy following IVF and embryo transfer (Hall et al., 1999
; Creus et al., 2000
). Inhibin B measured 46 days after starting COS was highly correlated with the number of oocytes retrieved (Eldar-Geva et al., 2000
; Fawzy et al., 2002
). However, it would be of greater clinical value to be able to predict follicular cohort size prior to starting GnRH analogue/FSH treatment, and it has been suggested that the inhibin B and estradiol responses to FSH administration can predict later oocyte collection (Dzik et al., 2000
; Elting et al., 2001
). Measurement of the number of antral follicles or ovarian volume by high resolution ultrasound scanning have also been shown in some but not all studies to predict ovarian response (Lass et al., 1997
; Tomas et al., 1997
; Chang et al., 1998
; Syrop et al., 1999
; Dumesic et al., 2001
). Generally, however, these endocrine and biophysical measures have not been studied prospectively or under basal conditions of differing endogenous FSH concentrations.
The primary objectives of our study were therefore (i) to investigate the relationships between the concentration of FSH in the early follicular phase, the endocrine responses of the ovary (inhibins, estradiol) to exogenous FSH stimulation and the number of antral follicles and ovarian volume, under different hormonal milieu, and (ii) to correlate these endocrine and biophysical measures with the number of oocytes retrieved following COS. The hormonal milieu under which these measures were investigated were the early follicular phase, i.e. during rising/high endogenous FSH concentrations, the luteal phase, i.e. during endogenous FSH suppression by ovarian hormones, and following GnRH analogue down-regulation, i.e. more marked hypogonadotrophism.
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Materials and methods |
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Controlled ovarian stimulation/IVF
Recombinant FSH was continued at a dose of 225 or 150 IU daily, depending on the subjects previous response to COS and the risk of OHSS. When three or more follicles with diameter 17 mm were observed, hCG (Profasi; Serono) s.c. 5000 or 10 000 IU was administered and transvaginal oocyte recovery performed
36 h later. Following IVF, not more than two embryos were transferred 48 h after oocyte recovery. Luteal support was provided with progesterone pessaries (Cyclogest; Shire, Basingstoke, UK) given for 2 weeks following embryo transfer. All subjects completed IVF treatment within 4 months of the first study visit. The women returned 2 weeks after embryo transfer for a pregnancy test. A positive result was followed up 2 weeks later by an ultrasound scan to confirm fetal viability.
Hormonal assays
Inhibin A and B and inhibin forms containing pro- and C immunoreactivity (pro-
C) were measured using two-site enzyme-linked immunosorbent assays using plates coated with specific monoclonal antibodies to the ßA and ßB subunits for inhibin A and B and the
subunit respectively as previously described (Groome et al., 1994
, 1995, 1996). Assay sensitivity for inhibin A was 2 pg/ml, for inhibin B was 7 pg/ml and for pro-
C was 3 pg/ml. Inter- and intra-plate coefficients of variation were <8% and <5% respectively.
Other hormones (FSH, estradiol and progesterone) were measured by radioimmunoassay as previously described (Backstrom et al., 1982).
Statistical analysis
All data are presented as mean ± SD values. Comparisons of paired hormone variables before and after administration of rFSH were performed with the Wilcoxon signed-ranks test, and the MannWhitney U-test was used for unpaired values. Respective differences in ovarian volume and AFC at visits 1, 3 and 5 were evaluated using the Friedman test. Linear regression analysis was employed to determine correlations hormone variables, AFC, subjects age and the number of oocytes recovered. Multiple regression analysis performed in stepwise fashion was used to evaluate the relative contribution of each variable to the number of oocytes recovered. Data were not transformed prior to analysis. Bonferroni correction was applied to P-values for correlations with multiple variables, hence P < 0.005 was taken as being statistically significant. P < 0.05 was considered significant for all other analyses.
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Results |
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Changes in biophysical measures
Significant differences in ovarian volume were detected with highest volume found in the luteal phase, and lowest volume after down-regulation (Figure 3). AFC, however, showed little variation between the endocrine phases (Figure 3).
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Correlations between hormonal responses and antral follicle count
Early follicular FSH concentration was weakly negatively correlated with AFC at all three endocrine phases investigated (Table II). The ovarian hormones showed variable correlations with AFC depending on the endocrine environment, and correlations with inhibin B in particular were increased following rFSH administration at all three time-points assesed. Inhibin A, pro-C and estradiol concentrations were poorly correlated with AFC other than between inhibin A and AFC following down-regulation and this was not increased by FSH. Thus rFSH stimulation of the small antral follicles in the early follicular phase uncovered the functionalitymorphology relationship for inhibin B, which did not exist with basal inhibin B or with the other hormones. The poor correlation between AFC and inhibin A and estradiol in the luteal phase is in keeping with the corpus luteum being the major source of these hormones at this stage of the menstrual cycle.
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After down-regulation, both inhibin A and B showed stronger correlations with oocyte number. These correlations were further increased after rFSH administration. The strongest correlation was with inhibin B. Estradiol and pro-C showed poor correlations with oocyte number, and there was no significant change after FSH injection.
Of the biophysical variables, AFC showed highly significant correlations with the number of oocytes recovered (Table IV). The best correlation was observed in the mid-luteal phase and was roughly similar to that of inhibin A after rFSH administration in the down-regulated phase (visit 6). Ovarian volume showed weaker correlations, close to the limit of statistical significance at all three states although highest after down-regulation.
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Relationships with age
The correlations between age and the endocrine measures were generally poor (e.g. early follicular FSH; r = 0.14, P = 0.33). In contrast, there was a significant relationship between age and AFC in the luteal and down-regulated phases (r = 0.47, P < 0.0005 and r = 0.50, P < 0.0005 respectively). The correlation with the other biophysical measures (early follicular AFC, ovarian volume at all three phases) were weak (r = 0.11 to 0.28). There was only a poor relationship between age and the number of oocytes recovered (r = 0.18, P = 0.22).
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Discussion |
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Serum inhibin concentrations showed the expected patterns, inhibin B being highest in the early follicular phase, inhibin A being highest in the luteal phase, and both being low after down-regulation (Groome et al., 1994, 1996; Lockwood et al., 1996
). Administration of rFSH resulted in increases in inhibin B concentration at all time-points. The proportional rise in inhibin B was greatest following down-regulation, with a similar rise during the luteal phase. Inhibin B is produced by the granulosa cells of antral follicles. When concentrations of FSH are low, such as occurs during the luteal phase of the cycle and after down-regulation with GnRH analogue, the secretion of inhibin B is minimal because even the healthy follicles are deprived of FSH. Following injection of rFSH, there was a prompt increase in the secretion of inhibin B, the concentration of which showed a close correlation with AFC reflecting the number of healthy follicles as they express their potential. As AFC differed little between the three time-points examined, these data indicate that the granulosa cells of small follicles are most sensitive to a rise in FSH when endogenous concentrations are low.
The changes in inhibin A were relatively unremarkable, although the relationships with inhibin B particularly after rFSH administration confirm the common source of both hormones, i.e. from the antral follicle population. The measurement of pro-C was of no predictive value either under basal conditions or after rFSH stimulation. The physiological role of this precursor peptide (if any) in regulation of ovarian or pituitary function is unknown. The correlation between estradiol and AFC was much weaker than that of inhibin B. The secretion of estradiol by the follicle is dependent on an adequate supply of androgen precursor from the theca layer which is stimulated by LH (Hillier, 1994
). Thus when the levels of gonadotrophins are low, such as during the luteal phase and after down-regulation, injection of LH as well as FSH is required to realise the full potential for estradiol secretion (Illingworth et al., 1996
). In contrast, LH has little effect on the production of inhibin B by the follicle although inhibin A secretion by the corpus luteum is sensitive to LH and hCG (but not FSH).
Interpretation of these data is based on the premise that the inhibins and estradiol are products of the ovary, and may therefore be anticipated to reflect ovarian activity. FSH is under feedback control by these hormones. FSH secretion thus reflects a summation of several positive and negative influences, yet is the prime determinant of follicular recruitment and growth. The present data show a relatively weak relationship between FSH concentration in the early follicular phase and AFC in all three endocrine states investigated. AFC did not vary significantly between the three endocrine states. Close correlations between inhibin B and AFC were observed at all three endocrine states after rFSH administration, despite mean inhibin B concentrations varying by >100% between them. Directly comparable data have not been previously obtained. In contrast, ovarian volume was demonstrated to differ between the endocrine states examined, being biggest during the luteal phase, reflecting the contribution of the corpus luteum, and lowest after down-regulation.
The relationship between these endocrine and biophysical measures and the number of oocytes recovered after COS was also investigated. This is of both scientific and clinical value. Non-invasive determination of the follicular pool may allow an improvement in prediction of women who may under- or over-respond to COS protocols. This has been the subject of many investigations (Gulekli et al., 1999; Bukman and Heineman, 2001
) but no clinically useful predictive test (i.e. sufficiently accurate and distinct in time from COS treatment) has emerged. The realization that inhibin B concentrations reflect the number of antral follicles present has allowed the demonstration that inhibin B concentrations during COS show a close relationship with the number of oocytes recovered (Eldar-Geva et al., 2000
; Fawzy et al., 2002
), and such a relationship, although much weaker, can also be demonstrated using basal early follicular phase inhibin B concentration in some (Seifer et al., 1997
; Hall et al., 1999
; Tinkanen et al., 1999
) but not all studies (Dumesic et al., 2001
). The present data confirm the lack of predictive value of basal ovarian hormone concentrations, with neither inhibin A, inhibin B nor estradiol showing a significant relationship to subsequent oocyte recovery although early follicular FSH concentration showed a strong correlation. However, following rFSH administration in the early follicular phase, inhibin B concentration showed a highly significant relationship. In the luteal phase, despite the larger increase in inhibin B concentration after rFSH administration, only a weak relationship with oocyte recovery was detected. The closest correlations were observed after down-regulation, both before and after rFSH administration. This is to be expected because it is these particular small follicles which in the next few days will be stimulated to pre-ovulatory size. This observation indicates the intrinsic variability over the period of a few weeks of the size of the recruitable cohort of follicles. In the clinical setting, the greater predictive power of endocrine measurements following down-regulation would need to be weighed against the value of prediction at an earlier time-point prior to initiation of COS treatment. Our findings extend previous demonstrations of relationships between inhibin B concentrations during the later stages of COS and the number of oocytes recovered (Hall et al., 1999
; Eldar-Geva et al., 2000
; Dumesic et al., 2001
) to both before the start of COS and after the first administration of rFSH. This indicates that assessing the hormonal sensitivity of follicular granulosa cells both prior to and after initial FSH administration has similar accuracy as a predictor of the number of oocytes recovered, as assessment delayed until follicular growth is well established. AFC showed a significant and similar correlation with oocyte number at all three states, as previously demonstrated in the early follicular phase (Chang et al., 1998
). Ovarian volume, however, showed relatively weak correlations with the number of oocytes recovered. Ovarian volume in the early follicular phase and after down-regulation was found to be a poor predictor of the number of oocytes recovered after COS (Tomas et al., 1997
; Tinkanen et al., 1999
; Dumesic et al., 2001
) although luteal phase ovarian volume did show predictive value in one study (Syrop et al., 1999
). Of the two biophysical measures assessed, AFC therefore appears to reflect more closely the ovarian reserve than does ovarian volume.
The investigation of both hormonal and biophysical variables allowed assessment of the relative value of these measures as predictors of oocyte number, both in the early follicular phase and after down-regulation. AFC and ovarian volume showed significant correlations with oocyte number, with coefficients of regression for AFC being similar to those of inhibin B after rFSH administration, consistent with the initial analysis showing close relationships between these markers of follicular activity. However, multiple regression analysis demonstrated that early follicular phase FSH and mid-luteal AFC were the only factors independently associated with oocyte number. Stimulated inhibin B concentrations reflected the potential follicular development of the ovary, but were not significantly associated with oocyte number when the biophysical data were included in the model.
In conclusion, these data extend our understanding of the relationships between follicular number, follicular functional activity and sensitivity to FSH, and the recruitable follicular population. FSH-stimulated inhibin B concentration may add to, but will not supplant, measurement of FSH concentration in the early follicular phase, and AFC appears to be of greater value in assessing the ovarian reserve than direct ovarian hormones. That the summative analysis of ovarian activity determined by the hypothalamus and gonadotroph as reflected in FSH secretion is superior to measurement of ovarian products should not be surprising, but illustrates present limitations in assessment of ovarian function.
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Acknowledgements |
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References |
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![]() ![]() ![]() ![]() ![]() ![]() ![]() |
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Backstrom, C.T., McNeilly, A.S., Leask, R. and Baird, D.T. (1982) Pulsatile secretion of LH, FSH, prolactin, oestradiol and progesterone during the human menstrual cycle. Clin. Endocrinol., 7, 2942.
Baird, D.T. (1999) Folliculogenesis and gonadotrophins. In Adashi, E.Y., Baird, D.T. and Crosignani, P.G. (eds), Gonadotrophins and Fertility in the Woman. Serono Fertility Series, Rome, Vol. 3, pp. 110.
Baird, D.T. and Pearson, S. (1998) Factors determining response to controlled ovarian stimulation (COS) for in vitro fertilisation (IVF). In Templeton, A., Cooke, I. and OBrien, P.M.S. (eds), Evidence-based Fertility Treatment. RCOG Press, London, pp. 274282.
Bukman, A. and Heineman, M.J. (2001) Ovarian reserve testing and the use of prognostic models in patients with subfertility. Hum. Reprod. Update, 7, 581590.
Burger, H.G., Groome, N.P. and Robertson, D.M. (1998) Both inhibin A and B respond to exogenous follicle-stimulating hormone in the follicular phase of the human menstrual cycle. J. Clin. Endocrinol. Metab., 83, 41676169.
Chang, M.Y., Chiang, C.H., Hsieh, T.T., Soong, Y.K. and Hsu, K.H. (1998) Use of the antral follicle count to predict the outcome of assisted reproductive technologies. Fertil. Steril., 69, 505510.[CrossRef][ISI][Medline]
Creus, M., Penarrubia, J., Fabregues, F., Vidal, E., Carmona, F., Casamitjana, R., Vanrell, J.A. and Balasch, J. (2000) Day 3 serum inhibin B and FSH and age as predictors of assisted reproduction treatment outcome. Hum. Reprod., 15, 23412346.
Dumesic, D.A., Damario, M.A., Session, D.R., Famuyide, A., Lesnick, T.G., Thornhill, A.R. and McNeilly, A.S. (2001) Ovarian morphology and serum hormone markers as predictors of ovarian follicle recruitment by gonadotrophins for in vitro fertilisation. J. Clin. Endocrinol. Metab., 86, 25382543.
Dzik, A., Lambert-Messerlian, G., Izzo, V.M., Soares, J.B., Pinotti, J.A. and Seifer, D.B. (2000) Inhibin B response to EFORT is associated with the outcome of oocyte retrieval in the subsequent in vitro fertilization cycle. Fertil. Steril., 74, 11141117.[CrossRef][ISI][Medline]
Eldar-Geva, T., Robertson, D.M., Cahir, N., Groome, N., Gabbe, M.P., Maclachlan, V. and Healy, D.L. (2000) Relationship between serum inhibin A and B and ovarian follicle development after a daily fixed dose administration of recombinant follicle-stimulating hormone. J. Clin. Endocrinol. Metab., 85, 607613.
Elting, M.W., Kwee, J., Schats, R., Rekers-Mombarg, L.T. and Schoemaker, J. (2001) The rise of estradiol and inhibin B after acute stimulation with follicle-stimulating hormone predict the follicle cohort size in women with polycystic ovary syndrome, regularly menstruating women with polycystic ovaries, and regularly menstruating women with normal ovaries. J. Clin. Endocrinol. Metab., 86, 15891595.
Erickson, G.F. (1986) An analysis of follicle development and ovum maturation. Semin. Reprod. Endocrinol., 4, 233.
Fabregues, F., Balasch, J., Creus, M., Carmona, F., Puerto, B., Quinto, L., Casamitjana, R. and Vanrell, J.A. (2000) Ovarian reserve test with human menopausal gonadotropin as a predictor of in vitro fertilization outcome. J. Assist. Reprod. Genet., 17, 1319.[CrossRef][ISI][Medline]
Faddy, M.J. and Gosden, R.G. (1996) A model conforming the decline in follicle numbers to the age of the menopause in women. Hum. Reprod., 11, 14841486.
Faddy, M.J., Gosden, R.G., Gougeon, A., Richardson, S.J. and Nelson, J.F. (1992) Accelerated disappearance of ovarian follicles in mid-life: implications for forecasting menopause. Hum. Reprod., 7, 13421346.[Abstract]
Fanchin, R., de Ziegler, D., Olivennes, F., Taieb, J., Dzik, A. and Frydman, R. (1994) Exogenous follicle stimulating hormone ovarian reserve test (EFORT): a simple and reliable screening test for detecting poor responders in in-vitro fertilization. Hum. Reprod., 9, 16071611.[Abstract]
Fawzy, M., Lambert, A., Harrison, R.F., Knight, P.G., Groome, N., Hennelly, B. and Robertson, W.R. (2002) Day 5 inhibin B levels in a treatment cycle are predictive of IVF outcome. Hum. Reprod., 17, 15351543.
Gougeon, A. (1996) Regulation of ovarian follicular development in primates: facts and hypotheses. Endocr. Rev., 17, 121155.[ISI][Medline]
Gougeon, A., Echochard, R. and Thalabard, J.C. (1994) Age-related changes of the population of human ovarian follicles: increase in the disappearance rate of non-growing and early-growing follicles in aging women. Biol. Reprod., 50, 653663.[Abstract]
Groome, N.P., Illingworth, P.J., OBrien, M., Cook, I., Ganesan, T.S. and Baird, D. (1994) Detection of dimeric inhibin throughout the human menstrual cycle by a 2-site enzyme immunoassay. Clin. Endocrinol., 6, 717723.
Groome, N.P., Illingworth, P.J., OBrien, M., Prindle, J., Weaver, K. and McNeilly, A.S. (1995) Quantification of inhibin pro-C containing forms in human serum by a new ultrasensitive two-site enzyme-linked immunosorbent assay. J. Clin. Endocrinol. Metab., 80, 29262932.[Abstract]
Groome, N.P., Illingworth, P.J., OBrien, M., Pai, R., Rodger, F.E., Mather, J. and McNeilly, A.S. (1996) Measurement of dimeric inhibin B throughout the menstrual cycle. J. Clin. Endocrinol. Metab., 81, 14011405.[Abstract]
Gulekli, B., Bulbul, Y., Onvural, A., Yorukoglu, K., Posaci, C., Demir, N. and Erten, O. (1999) Accuracy of ovarian reserve tests. Hum. Reprod., 14, 28222826.
Hall, J.E., Welt, C.K. and Cramer, D.W. (1999) Inhibin A and inhibin B reflect ovarian function in assisted reproduction but are less useful at predicting outcome. Hum. Reprod., 14, 409415.
Hayes, F.J., Hall, J.E., Boepple, P.A. and Crowley, W.F.J. (1998) Differential control of gonadotrophin secretion in the human: endocrine role of inhibin. J. Clin. Endocrinol. Metab., 83, 18351841.
Hillier, S.G. (1994) Current concepts of the roles of follicle stimulating hormone and luteinizing hormone in folliculogenesis. Hum. Reprod., 9, 188191.[Abstract]
Illingworth, P.J., Groome, N.P., Duncan, W.C., Grant, V., Tovanabutra, S., Baird, D.T. and McNeilly, A.S. (1996) Measurement of circulating inhibin forms during the establishment of pregnancy. J. Clin. Endocrinol. Metab., 81, 14711475.[Abstract]
Jaatinen, T.A., Penttila, T.L., Kaipia, A., Ekfors, T., Parvinen, M. and Toppari, J. (1994) Expression of inhibin alpha, beta A and beta B messenger ribonucleic acids in the normal human ovary and in polycystic ovarian syndrome. J. Endocrinol., 143, 127137.[Abstract]
Lahlou, N., Chabbert-Buffet, N., Christin-Maitre, S., Le Nestour, E., Roger, M. and Bouchard, P. (1999) Main inhibitor of follicle stimulating hormone in the lutealfollicular transition: inhibin A, oestradiol, or inhibin B? Hum. Reprod., 14, 11901193.
Lambert-Messerlian, G.M., Hall, J.E., Sluss, P.M., Taylor, A.E., Martin, K.A., Groome, N.P., Crowley, W.F.J. and Schneyer, A.L. (1994) Relatively low levels of dimeric inhibin circulate in men and women with polycystic ovarian syndrome using a specific two-site enzyme-linked immunosorbent assay. J. Clin. Endocrinol. Metab., 79, 4550.[Abstract]
Lass, A., Skull, J., McVeigh, E., Margara, R. and Winston, R.M. (1997) Measurement of ovarian volume by transvaginal sonography before ovulation induction with human menopausal gonadotrophin for in-vitro fertilization can predict poor response. Hum. Reprod., 12, 294297.[Abstract]
Licciardi, F.L., Liu, H.C. and Rosenwaks, Z. (1995) Day 3 estradiol serum concentrations as prognosticators of ovarian stimulation response and pregnancy outcome in patients undergoing in vitro fertilization. Fertil. Steril., 64, 991994.[ISI][Medline]
Lockwood, G.M., Muttukrishna, S., Groome, N.P., Knight, P.G. and Ledger, W.L. (1996) Circulating inhibins and activin A during GnRH-analogue down-regulation and ovarian hyperstimulation with recombinant FSH for in-vitro fertilisationembryo transfer. Clin. Endocrinol., 45, 741748.[ISI][Medline]
Loumaye, E., Billion, J.M., Mine, J.M., Psalti, I., Pensis, M. and Thomas, K. (1990) Prediction of individual response to controlled ovarian hyperstimulation by means of a clomiphene citrate challenge test. Fertil. Steril., 53, 295301.[ISI][Medline]
Navot, D., Rosenwaks, Z. and Margalioth, E.J. (1987) Prognostic assessment of female fecundity. Lancet, 2, 645647.[CrossRef][Medline]
Padilla, S.L., Bayati, J. and Garcia, J.E. (1990) Prognostic value of the early serum estradiol response to leuprolide acetate in in vitro fertilization. Fertil. Steril., 53, 288294.[ISI][Medline]
Phelps, J.Y., Levine, A.S., Hickman, T.N., Zacur, H.A., Wallach, E.E. and Hinton, E.L. (1998) Day 4 estradiol levels predict pregnancy success in women undergoing controlled ovarian hyperstimulation for IVF. Fertil. Steril., 69, 10151019.[CrossRef][ISI][Medline]
Rabinovici, J., Spencer, S.J., Doldi, N., Goldsmith, P.C., Schwall, R. and Jaffe, R.B. (1992) Activin-A as an intraovarian modulator: actions, localization, and regulation of the intact dimer in human ovarian cells. J. Clin. Invest., 89, 15281536.[ISI][Medline]
Ranieri, D.M., Quinn, F., Makhlouf, A., Khadum, I., Ghutmi, W., McGarrigle, H., Davies, M. and Serhal, P. (1998) Simultaneous evaluation of basal follicle-stimulating hormone and 17 beta-estradiol response to gonadotropin-releasing hormone analogue stimulation: an improved predictor of ovarian reserve. Fertil. Steril., 70, 227233.[CrossRef][ISI][Medline]
Ravhon, A., Lavery, S., Michael, S., Donaldson, M., Margara, R., Trew, G. and Winston, R. (2000) Dynamic assays of inhibin B and oestradiol following buserelin acetate administration as predictors of ovarian response in IVF. Hum. Reprod., 15, 22972301.
Roberts, V.J., Barth, S., Elroeiy, A. and Yen, S.C.C. (1993) Expression of inhibin/activin subunits and follistatin messenger ribonucleic acids and proteins in ovarian follicles and the corpus luteum during the human menstrual cycle. J. Clin. Endocrinol. Metab., 77, 14021410.[Abstract]
Seifer, D.B., Gardiner, A.C., Lambert-Messerlian, G., Blazer, A.S., Hogan, J.W. and Berk, C.A. (1997) Day 3 serum inhibin-B is predictive of assisted reproductive technologies outcome. Fertil. Steril., 67, 110114.[CrossRef][ISI][Medline]
Smotrich, D.B., Widra, E.A., Gindoff, P.R., Levy, M.J., Hall, J.L. and Stillman, R.J. (1995) Prognostic value of day 3 estradiol on in vitro fertilization outcome. Fertil. Steril., 64, 11361140.[ISI][Medline]
Syrop, C.H., Dawson, J.D., Husman, K.J., Sparks, A.E. and Van Voorhis, B.J. (1999) Ovarian volume may predict assisted reproductive outcomes better than follicle stimulating hormone concentration on day 3. Hum. Reprod., 14, 17521756.
Tanbo, T., Dale, P.O., Abyholm, T. and Stokke, K.T. (1989) Follicle-stimulating hormone as a prognostic indicator in clomiphene citrate/human menopausal gonadotrophin-stimulated cycles for in-vitro fertilization. Hum. Reprod., 4, 647650.[Abstract]
Tinkanen, H., Blauer, M., Laippala, P., Tuohimaa, P. and Kujansuu, E. (1999) Prognostic factors in controlled ovarian hyperstimulation. Fertil. Steril., 72, 932936.[CrossRef][ISI][Medline]
Tomas, C., Nuojua-Huttunen, S. and Martikainen, H. (1997) Pretreatment transvaginal ultrasound examination predicts ovarian responsiveness to gonadotrophins in in-vitro fertilization. Hum. Reprod., 12, 220223.[Abstract]
Welt, C.K., Martin, K.A., Taylor, A.E., Lambert-Messerlian, G.M., Crowley, W.F.J., Smith, J.A., Schoenfeld, D.A. and Hall, J.E. (1997) Frequency modulation of follicle-stimulating hormone (FSH) during the follicular-luteal transition: evidence for FSH control of inhibin B in normal women. J. Clin. Endocrinol. Metab., 82, 26452652.
Winslow, K.L., Toner, J.P., Brzyski, R.G., Oehninger, S.C., Acosta, A.A. and Muasher, S.J. (1991) The gonadotropin-releasing hormone agonist stimulation testa sensitive predictor of performance in the flare-up in vitro fertilization cycle. Fertil. Steril., 56, 711717.[ISI][Medline]
Yamoto, M., Minami, S. and Nakano, R. (1993) Immunohistochemical localization of inhibin subunits in polycystic ovary. J. Clin. Endocrinol. Metab., 77, 859862.[Abstract]
Submitted on July 2002; accepted on September 6, 2002