Dynamic analysis and control of a hybrid lower limb rehabilitation robot to reduce human-robot interaction forces

This study presents a model of cooperation between two planar manipulators including an orthosis and a programmable plate in form of a hybrid lower limb rehabilitation robot, which was designed and built at the University of Guilan. The aims of cooperation are to distribute the power required to move between the cooperative manipulators and also reduce the interaction forces between orthosis and leg. The cooperation is performed with two modes using the adjustment of the plate forces, a constant force in the vertical direction (CFV) and variant force proportional to orthosis torque (VFPOT). Kinematic and dynamic analysis of the hybrid lower limb rehabilitation robot and its control are also discussed in this study. The performance and effectiveness of the proposed hybrid robot are demonstrated on a healthy person in real-time. Each walking trial lasted 60 s and repeated 20 times for every mode. The walking speed was considered to be 1.5 km/h and weight compensator was adjusted with a constant weight unloading level of 70%. The results show that the VFPOT mode leads to a 45% reduction in the driving torque of the hip and knee joints compared to orthosis-only. This reduction is expected to reduce interaction force at the connection straps. So, it provides more patient comfort and safety, which can be effective in improving the time and process of rehabilitation.

High singleton live birth rate following classical ovulation induction in normogonadotrophic anovulatory infertility (WHO 2)

BACKGROUND

Medical induction of ovulation using clomiphene citrate (CC) as first line and exogenous gonadotrophins as second line forms the classical treatment algorithm in normogonadotrophic anovulatory infertility. Because the chances of success following classical ovulation induction are not well established, a shift in first-line therapy can be observed towards alternative treatment. The study aim was to: (i) reliably assess the probability of singleton live birth following classical induction of ovulation; and (ii) construct a prediction model, based on individual patient characteristics assessed upon standardized initial screening, to help identify patients with poor chances of success.

METHODS

A total of 240 consecutive women visiting a specialist academic fertility unit with a history of infertility, oligomenorrhoea or amenorrhoea, and normal FSH and estradiol serum concentrations (WHO group 2) was prospectively followed. The women had not been previously treated with ovulation-inducing agents. All patients commenced with CC. Patients who did not ovulate within three treatment cycles of incremental daily doses up to 150 mg for 5 consecutive days or ovulatory CC patients who did not conceive within six cycles, subsequently underwent gonadotrophin induction of ovulation applying a step-down dose regimen. The main outcome measure was pregnancy resulting in singleton live birth. Cox regression was used to construct a multivariable prediction model.

RESULTS

Overall, there were 134 pregnancies ending in a singleton live birth (56% of women). The cumulative pregnancy rate after 12 and 24 months of follow-up was 50% and 71% respectively. Polycystic ovary syndrome (PCOS) patients (49%), clearly non-PCOS patients (13%) and the in-between group did not differ in prognosis (P = 0.9). The multivariable Cox regression model contained the woman's age, the insulin:glucose ratio and duration of infertility. With a cut-off value of 30% for low chance, the model predicted probabilities at 12 months lower than this cut-off for 25 out of 240 patients (10.4%).

CONCLUSIONS

Classical ovulation induction produces very good results in normogonadotrophic anovulatory infertility. Alternative treatment options may not be indicated as first-line therapy in these patients, except for subgroups with poor prognosis. These women can be identified by older age, longer duration of infertility and higher insulin:glucose ratio.

IVF outcome in anovulatory infertility (WHO group 2)--including polycystic ovary syndrome--following previous unsuccessful ovulation induction

This follow-up study represents IVF treatment characteristics and outcomes in women with World Health Organization (WHO) group 2 anovulatory infertility after previous unsuccessful ovulation induction compared with controls. Furthermore, the possibility of initial screening parameters of these anovulatory women to predict IVF outcome was examined. Twenty-six patients with WHO 2 anovulatory infertility who failed to achieve a live birth following previous induction of ovulation (using clomiphene citrate as first line and exogenous FSH as second line) were compared with 26 IVF patients with tubal infertility matched for age, treatment period and treatment regimen. The WHO 2 patients underwent 49 IVF cycles, whereas the normo-ovulatory controls underwent 46 cycles. In WHO 2 patients 15 cycles were cancelled compared with six cycles in controls (P = 0.04). Cycles were predominantly cancelled due to insufficient response (P = 0.04). In cases in whom the cycle was cancelled, body mass index (BMI) was significantly higher (P < 0.001) in WHO 2 women compared with controls. Overall live birth rates were comparable (P = 0.9). Obese women suffering from WHO 2 anovulatory infertility are at an increased risk of having their IVF cycle cancelled due to insufficient response. Once oocyte retrieval is achieved, live birth rates are comparable with controls.

Prediction of chances for success or complications in gonadotrophin ovulation induction in normogonadotrophic anovulatory infertility

This follow-up study evaluated whether initial screening characteristics predict treatment outcome of gonadotrophin induction of ovulation. One hundred and fifty-four women with normogonadotrophic anovulatory infertility for whom clomiphene citrate induction of ovulation was unsuccessful were included in the present study. Daily FSH injections were initiated on day 3-5 after spontaneous or progestagen-induced withdrawal bleeding. In most patients, a dose finding low-dose step-up regimen was applied during the first treatment cycle in order to identify the individual FSH response dose. In all subsequent cycles, a step-down protocol was applied. Initial serum concentrations of LH, testosterone and androstenedione were significant predictors for the probability of multi-follicular development. FSH treatment resulted in a total of 67 (44%) ongoing pregnancies. Comparing those women who did, versus those who did not, achieve an ongoing pregnancy in a multivariate Cox regression analysis, initial serum insulin-like growth factor-I (IGF-I), testosterone and women's age entered into the final model (AUC = 0.67). The individual treatment outcome following gonadotrophin induction of ovulation may be predicted by initial screening characteristics.

New approach to polycystic ovary syndrome and other forms of anovulatory infertility

Anovulation can be classified in the clinic on the basis of serum hormone assays. Low gonadotropins along with low estrogen concentrations are suggestive of a central origin of the disease, whereas low estrogen levels along with elevated gonadotropins indicate a primary defect at the ovarian level. Most anovulatory patients (approximately 80%) present with serum FSH and estradiol levels within the normal range (World Health Organization class II). Polycystic ovary syndrome (PCOS) is a common but poorly defined heterogeneous clinical entity. Historically, characteristic ovarian abnormalities represented a hallmark of the syndrome. Because several etiological factors may lead to a similar end point (i.e., polycystic ovaries), the development of a clinically applicable classification of the syndrome has proven difficult. Clinical, morphological, biochemical, endocrine, and, more recently, molecular studies have identified an array of underlying abnormalities and added to the confusion concerning the pathophysiology of the disease. Despite the vast literature regarding the etiology and classification of PCOS, no consensus has been reached regarding the validity of criteria used to diagnose the syndrome. For instance, the significance of elevated serum luteinizing hormone (LH) concentrations, insulin resistance or polycystic-appearing ovaries assessed by ultrasound for PCOS diagnosis remains uncertain. In contrast, hyperandrogenism and chronic anovulation generally are believed to be mandatory diagnostic features. Patients with PCOS might visit a dermatologist for hirsutism, a generalist, or internist for complaints related to obesity or a gynecologist for irregular or absent bleeding. However, most patients seek the care of a gynecologist because of cycle abnormalities (oligomenorrhea) and infertility. In PCOS, serum FSH and estradiol (E2) levels are usually found to be within the (broad) normal ranges, whereas LH may either be normal or elevated. Because PCOS with normal or high LH does not seem to represent different clinical entities, it seems justifiable to consider this syndrome as a subgroup of WHO-II patients, although estrogen levels may be tonically elevated in these patients. This review will focus on characteristics of the heterogeneous group of WHO-II patients in an attempt to identify factors involved in the etiology and possible ovulation induction outcome of PCOS.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader will be able to outline the current classification of anovulatory infertility and to explain the characteristics and features used for classification.

Global gene profiling in human endometrium during the window of implantation

Implantation in humans is a complex process that is temporally and spatially restricted. Over the past decade, using a one-by-one approach, several genes and gene products that may participate in this process have been identified in secretory phase endometrium. Herein, we have investigated global gene expression during the window of implantation (peak E2 and progesterone levels) in well characterized human endometrial biopsies timed to the LH surge, compared with the late proliferative phase (peak E2 level) of the menstrual cycle. Tissues were processed for poly(A(+)) RNA and hybridization of chemically fragmented, biotinylated cRNAs on high density oligonucleotide microarrays, screening for 12,686 genes and expressed sequence tags. After data normalization, mean values were obtained for gene readouts and fold ratios were derived comparing genes up- and down-regulated in the window of implantation vs. the late proliferative phase. Nonparametric testing revealed 156 significantly (P < 0.05) up-regulated genes and 377 significantly down-regulated genes in the implantation window. Up-regulated genes included those for cholesterol trafficking and transport [apolipoprotein (Apo)E being the most induced gene, 100-fold], prostaglandin (PG) biosynthesis (PLA2) and action (PGE2 receptor), proteoglycan synthesis (glucuronyltransferase), secretory proteins [glycodelin, mammaglobin, Dickkopf-1 (Dkk-1, a Wnt inhibitor)], IGF binding protein (IGFBP), and TGF-beta superfamilies, signal transduction, extracellular matrix components (osteopontin, laminin), neurotransmitter synthesis (monoamine oxidase) and receptors (gamma aminobutyric acid A receptor pi subunit), numerous immune modulators, detoxification genes (metallothioneins), and genes involved in water and ion transport [e.g. Clostridia Perfringens Enterotoxin (CPE) 1 receptor (CPE1-R) and K(+) ion channel], among others. Down-regulated genes included intestinal trefoil factor (ITF) [the most repressed gene (50-fold)], matrilysin, members of the G protein-coupled receptor signaling pathway, frizzled-related protein (FrpHE, a Wnt antagonist), transcription factors, TGF-beta signaling pathway members, immune modulators (major histocompatibility complex class II subunits), and other cellular functions. Validation of select genes was conducted by Northern analysis and RT-PCR using RNA from endometrial biopsies obtained in the proliferative phase and the implantation window and by RT-PCR using RNA from cultured endometrial epithelial and stromal cells. These approaches confirmed up-regulation of genes corresponding to IGFBP-1, glycodelin, CPE1-R, Dkk-1, mammaglobin, and ApoD and down-regulation for PR membrane component 1, FrpHE, matrilysin, and ITF, as with the microarray data. Cultured endometrial epithelial cells were found to express mRNAs for glycodelin, CPE-1R, Dkk-1, the gamma aminobutyric acid A receptor pi subunit, mammaglobin, matrilysin, ITF and PR membrane component 1. The expression of IGFBP-1, CPE1-R, Dkk-1, and ApoD mRNAs increased upon decidualization of stromal cells in vitro with progesterone after E2 priming, whereas FrpHE decreased, consistent with the microarray results. Overall, the data demonstrate numerous genes and gene families not heretofore recognized in human endometrium or associated with the implantation process. Reassuringly, several gene products, known to be differentially expressed in the implantation window or in secretory endometrium, were verified, and the striking regulation of select secretory proteins, water and ion channels, signaling molecules, and immune modulators underscores the important roles of these systems in endometrial development and endometrial-embryonic interactions. In addition, the current study validates using high density oligonucleotide microarray technology to investigate global changes in gene expression in human endometrium.

Identification and regulation of the IGFBP-4 protease and its physiological inhibitor in human trophoblasts and endometrial stroma: evidence for paracrine regulation of IGF-II bioavailability in the placental bed during human implantation

The IGF family plays an important role in implantation and placental physiology. IGF-II is abundantly expressed by placental trophoblasts, and IGF binding protein (IGFBP)-4, a potent inhibitor of IGF actions, is the second most abundant IGFBP in the placental bed, expressed exclusively by the maternal decidua. Proteolysis of IGFBP-4 results in decreased affinity for IGF peptides, thereby enhancing IGF actions. In the current study, we have identified the IGFBP-4 protease and its inhibitor in human trophoblast and decidualized endometrial stromal cell cultures, and we have investigated their regulation in an effort to understand control of IGF-II bioavailability at the placental-decidual interface in human implantation. IGFBP-4 protease activity was detected in conditioned media (CM) from human trophoblasts and decidualized endometrial stromal cells using (125)I-IGFBP-4 substrate. Identification of the IGFBP-4 protease as pregnancy-associated plasma protein-A (PAPP-A) was confirmed by specific immunoinhibition and immunodepletion of the IGFBP-4 protease activity with specific PAPP-A antibodies. The IGFBP-4 protease activity was IGF-II-dependent in trophoblast CM. In decidualized stromal CM, PAPP-A/IGFBP-4 protease activity was also IGF-II-dependent, but was evident only when IGF-II was added in molar excess of the predominant IGFBP in decidualized stromal cell CM, IGFBP-1, supporting bioavailable IGF-II as a key cofactor of IGFBP-4 proteolysis by PAPP-A. Cultured first and second trimester human trophoblasts (n = 5) secreted PAPP-A into CM with mean +/- SEM levels of 172.4 +/- 32.8 mIU/liter.10(5) cells, determined by specific ELISA. PAPP-A in trophoblast CM (n = 3) and did not change in the presence of IGF-II (1-100 ng/ml). Cultured human endometrial stromal cells (n = 4) secreted low levels of PAPP-A (6.25 +/- 3.6 mIU/liter.10(5) cells). A physiological inhibitor of PAPP-A, the proform of eosinophil major basic protein (proMBP), was detected in trophoblast CM at levels of 1853 +/- 308 mIU/liter.10(5) cells, determined by specific ELISA, and was nearly undetectable in CM of human endometrial stromal cells. Upon in vitro decidualization of endometrial stromal cells with progesterone, PAPP-A levels in CM increased nearly 9-fold without a concomitant change in proMBP. In contrast to the experiments with trophoblasts, IGF-II and the IGF analogues, Leu(27) IGF-II, and Des (1-6) IGF-II, resulted in a dose-dependent decrease of PAPP-A levels in decidualized endometrial stromal CM by 70-90%, and a dose-dependent increase in proMBP of 14- to 41-fold. The data demonstrate conclusively that the IGF-II-dependent IGFBP-4 protease of human trophoblast and decidual origin is PAPP-A. Furthermore, the differential regulation of decidual PAPP-A and proMBP by insulin-like peptides supports a role for trophoblast-derived IGF-II as a paracrine regulator of these maternal decidual products that have the potential to regulate IGF-II bioavailability at the trophoblast-decidual interface. Overall, the data underscore potential roles for a complex family of enzyme (PAPP-A), substrate (IGFBP-4), inhibitor (proMBP), and cofactor (IGF-II) in the placental bed during human implantation.

A nomogram to predict the probability of live birth after clomiphene citrate induction of ovulation in normogonadotropic oligoamenorrheic infertility

OBJECTIVE

To establish whether initial screening characteristics of normogonadotropic anovulatory infertile women can aid in predicting live birth after induction of ovulation with clomiphene citrate (CC).

DESIGN

Prospective longitudinal single-center study.

SETTING

Specialist academic fertility unit.

PATIENT(S)

Two hundred fifty-nine couples with a history of infertility, oligoamenorrhea, and normal follicle-stimulating hormone (FSH) concentrations who have not been previously treated with any ovulation-induction medication.

INTERVENTION(S)

50, 100, or 150 mg of oral CC per day, for 5 subsequent days per cycle.

MAIN OUTCOME MEASURE(S)

Conception leading to live birth after CC administration.

RESULT(S)

After receiving CC, 98 (38%) women conceived, leading to live birth. The cumulative live birth rate within 12 months was 42% for the total study population and 56% for the ovulatory women who had received CC. Factors predicting the chances for live birth included free androgen index (testosterone/sex hormone-binding globulin ratio), body mass index, cycle history (oligomenorrhea versus amenorrhea), and the woman's age.

CONCLUSION(S)

It is possible to predict the individual chances of live birth after CC administration using two distinct prediction models combined in a nomogram. Applying this nomogram in the clinic may be a step forward in optimizing the decision-making process in the treatment of normogonadotropic anovulatory infertility. Alternative first line of treatment options could be considered for some women who have limited chances for success.

Prediction of the individual follicle-stimulating hormone threshold for gonadotropin induction of ovulation in normogonadotropic anovulatory infertility: an approach to increase safety and efficiency

OBJECTIVE

To predict the FSH response (threshold) dose in normogonadotropic, anovulatory infertile women undergoing gonadotropin induction of ovulation.

DESIGN

Prospective longitudinal clinical study.

SETTING

Specialist academic fertility unit.

PATIENT(S)

Normogonadotropic, oligoamenorrheic, infertile women who were resistant to clomiphene citrate or in whom clomiphene citrate therapy had failed.

INTERVENTION(S)

Daily exogenous FSH administration in a low-dose, step-up regimen.

MAIN OUTCOME MEASURE(S)

The FSH dose on the day of ovarian response (follicle growth > 10 mm in diameter).

RESULT(S)

Multivariate analysis was used to devise the following equation to predict the individual FSH response dose (75 to >187 IU/d) before initiation of therapy: [4 body mass index (in kg/m(2))] + [32 clomiphene citrate resistance (yes = 1 or no = 0)] + [7 initial free insulin-like growth factor-I (in ng/mL)] + [6 initial serum FSH level (in IU/L)] - 51. The SE of the predicted dose is 35 IU.

CONCLUSION(S)

The individual FSH response dose for gonadotropin induction of ovulation in anovulatory infertile women can be predicted on the basis of initial screening characteristics. The prediction model developed in this study may increase the safety and efficiency of low-dose gonadotropin protocols (step-up and step-down) by correctly determining the appropriate starting dose for a given patient.

Age-related differences in features associated with polycystic ovary syndrome in normogonadotrophic oligo-amenorrhoeic infertile women of reproductive years

OBJECTIVE

To assess the effect of age on clinical, endocrine and sonographic features associated with polycystic ovary syndrome (PCOS) in normogonadotrophic anovulatory infertile women of reproductive years.

DESIGN

Cross-sectional study.

METHODS

Four hundred and seventy-two oligo-amenorrhoeic infertile patients, presenting with normal FSH and oestradiol concentrations, aged 17-42 years underwent a standardised initial evaluation including: cycle history, body mass index, waist-to-hip ratio and transvaginal ultrasound scanning of ovaries. Fasting blood samples were obtained for extensive endocrine evaluation. Cycle duration, serum levels of gonadotrophins, androgens, oestradiol, insulin, glucose, inhibin B as well as mean number of follicles, ovarian volume and ovarian stroma echogenicity were assessed.

RESULTS

Older women had significantly lower LH and androgen and inhibin B serum levels. Similarly, older women presented with a reduced number of ovarian follicles. Age was inversely correlated with cycle duration (r=-0.112, P=0.02), LH (r=-0.154, P=0.001), testosterone (r=-0.194, P=0.001), androstenedione (r=-0.170, P=0.001), dehydroepiandrosterone (r=-0.157, P=0.001), insulin (r=-0.126, P=0.02), inhibin B (r=-0.118, P=0.03) serum levels and mean follicle number (r=-0.100, P=0.03). A positive correlation was observed between age and glucose to insulin ratio (r=0.138, P=0.009).

CONCLUSIONS

Advanced age in normogonadotrophic anovulatory infertile women is associated with lower LH and androgen levels and with a decreased number of ovarian follicles. Although during reproductive years observed differences are relatively small, these age-related changes may affect the observed incidence of PCOS.

Absent biologically relevant associations between serum inhibin B concentrations and characteristics of polycystic ovary syndrome in normogonadotrophic anovulatory infertility

BACKGROUND

Dominant follicle selection is disturbed in normogonadotrophic anovulatory infertility [World Health Organization (WHO) 2] and remaining early antral follicles are either healthy or atretic. This study was conducted to investigate whether inhibin B serum concentrations (produced by healthy small antral follicles) represent the extent of ovarian abnormalities in WHO 2 women and patients with polycystic ovarian syndrome (PCOS), constituting a subgroup of WHO 2 patients.

METHODS AND RESULTS

Ultrasonographic and endocrine characteristics in 379 WHO 2 patients and 30 normo-ovulatory controls were compared. In the WHO 2 patients, the PCOS subgroup and the controls, inhibin B concentrations were similar. Inhibin B concentrations were weakly but significantly correlated with the total number of ovarian follicles (r = 0.282; P < 0.001), LH (r = 0.347; P < 0.001), and testosterone (r = 0.269; P < 0.001) but not with serum oestradiol concentrations (r = 0.057). Most (71%) patients with elevated inhibin B also presented with increased concentrations of LH and/or hyperandrogenaemia. In a subgroup of 190 subjects, classified as PCOS based on hyperandrogenaemia and polycystic ovaries, elevated inhibin B concentrations were found in 23% of cases. Aforementioned correlations were similar in PCOS as in WHO 2 patients.

CONCLUSION

In conclusion, inhibin B serum concentrations are normal in WHO 2 and PCOS women, suggesting a normal number of healthy early antral follicles despite increased overall follicle numbers in PCOS.

Free androgen index and leptin are the most prominent endocrine predictors of ovarian response during clomiphene citrate induction of ovulation in normogonadotropic oligoamenorrheic infertility

We have previously demonstrated that obese hyperandrogenic amenorrheic women are less likely to ovulate after clomiphene citrate (CC) medication. The present study was designed to identify whether additional endocrine screening characteristics, all potentially involved in ovarian dysfunction in 182 normogonadotropic oligoamenorrheic infertile women, are associated with ovarian response, which may improve overall prediction of CC-resistant anovulation. Standardized endocrine screening took place before initiation of CC medication (50 mg/day; increasing doses up to 150 mg/day if required) from cycle days 3-7. Screening included serum assays for fasting insulin and glucose, insulin-like growth factor I (IGF-I), IGF-binding protein-1 (IGFBP-1), IGFBP-3, free IGF-I, inhibin B, leptin, and vascular endothelial growth factor. Forty-two women (22% of the total group) did not ovulate at the end of follow-up (a total number of 325 cycles were analyzed). Fasting serum insulin, insulin/glucose ratio, IGFBP-1, and leptin were all significantly different in univariate analyses (P < or = 0.02), comparing CC responders vs. nonresponders. Forward stepwise multivariate analyses in combination with factors reported earlier for prediction of patients remaining anovulatory after CC revealed a prediction model including 1) free androgen index (FAI = testosterone/sex hormone-binding globulin ratio), 2) cycle history (oligomenorrhea or amenorrhea), 3) leptin level, and 4) mean ovarian volume. These data suggest that decreased insulin sensitivity, hyperandrogenemia, and obesity, all associated with polycystic ovary syndrome, are prominent factors involved in ovarian dysfunction, preventing these ovaries from responding to stimulation by raised endogenous FSH levels due to CC medication. By using leptin instead of body mass index or waist to hip ratio, the previous model for prediction of patients remaining anovulatory after CC medication could be slightly improved (area under the curve from 0.82-0.85). This may indicate that leptin is more directly involved in ovarian dysfunction in these patients. The capability of insulin and IGFBP-1 to predict patients who remain anovulatory after CC disappears when FAI enters into the model due to a significant correlation between FAI and these endocrine parameters. This suggests that markers for insulin sensitivity (e.g. IGFBP-1 and insulin) are associated with abnormal ovarian function through its correlation with androgens, whereas leptin is directly involved in ovarian dysfunction.

Predictors of chances to conceive in ovulatory patients during clomiphene citrate induction of ovulation in normogonadotropic oligoamenorrheic infertility

The present prospective follow-up study was designed to identify whether clinical, endocrine, or ultrasound characteristics assessed by standardized initial screening of normogonadotropic oligo/amenorrheic infertile patients could predict conception in 160 women who reached ovulation after clomiphene citrate (CC) medication. Additional inclusion criteria were total motile sperm count of the partner above 1 million and a negative history for any tubal disease. Daily CC doses of 50 mg (increasing up to 150 mg in case of absent ovarian response) from cycle days 3-7 were used. First conception (defined as a positive urinary pregnancy test) was the end point for this study. A cumulative conception rate of 73% was reached within 9 CC-induced ovulatory cycles. Patients who did conceive presented more frequently with lower age (P < 0.0001) and amenorrhea (P < 0.05) upon initial screening. In a univariate analysis, patients with elevated initial serum LH concentrations (>7.0 IU/L) had a higher probability of conceiving (P < 0.01). In a multivariate analysis, age and cycle history (oligomenorrhea vs. amenorrhea) were identified as the only significant parameters for prediction of conception. These observations suggest that there is more to be gained from CC ovulation induction in younger women presenting with profound oligomenorrhea or amenorrhea. Screening characteristics involved in the prediction of ovulation after CC medication in normogonadotropic oligo/amenorrheic patients (body weight and hyperandrogenemia, as shown previously) are distinctly different from predictors of conception in ovulatory CC patients (age and the severity of cycle abnormality). This disparity suggests that the FSH threshold (magnitude of FSH required for stimulation of ongoing follicle growth and ovulation) and oocyte quality (chances for conception in ovulatory cycles) may be differentially regulated.

Predictors of patients remaining anovulatory during clomiphene citrate induction of ovulation in normogonadotropic oligoamenorrheic infertility

The diagnostic criteria used to identify patients suffering from polycystic ovary syndrome remain controversial. The present prospective longitudinal follow-up study was designed to identify whether certain criteria assessed during standardized initial screening could predict the response to ovulation induction with clomiphene citrate (CC) in 201 patients presenting with oligomenorrhea or amenorrhea and infertility. Serum FSH levels were within the normal range (1-10 IU/L), and all patients underwent spontaneous or progestin-induced withdrawal bleeding. Initial CC doses were 50 mg daily for 5 days starting on cycle day 3. In the case of an absent response, doses were increased to 100 and 150 mg daily in subsequent cycles. First ovulation with CC was used as the end point. After a complete follow-up (in the case of a nonresponse, at least 3 treatment cycles with daily CC doses up to 150 mg), 156 patients (78%) ovulated. The free androgen index (FAI = testosterone/sex hormone-binding globulin ratio), body mass index (BMI), cycle history (oligomenorrhea vs. amenorrhea), serum androgen (testosterone and/or androstenedione) levels, and mean ovarian volume assessed by transvaginal sonography were all significantly different (P < 0.01) in responders from those in nonresponders. FAI was chosen to be the best predictor in univariate analysis. The area under the receiver operating characteristics curve in a multivariate prediction model including FAI, BMI, cycle history, and mean ovarian volume was 0.82. Patients whose ovaries are less likely to respond to stimulation by FSH due to CC treatment can be predicted on the basis of initial screening characteristics, such as FAI, BMI, cycle history (oligomenorrhea or amenorrhea), and mean ovarian volume. These observations may add to ongoing discussion regarding etiological factors involved in ovarian dysfunction in these patients and classification of normogonadotropic anovulatory infertile women.