Clinical, endocrinologic, and intraovarian prostaglandin F responses to H-1 receptor blockade in the ovarian hyperstimulation syndrome: studies in the rabbit model

Treatment of Ovarian Hyperstimulation Syndrome in a Mouse Model by Cannabidiol, an Angiogenesis Pathway Inhibitor

Studies suggest that ovarian hyperstimulation syndrome (OHSS) can be treated by reducing the level of vascular endothelial growth factor (VEGF). However, due to the side effects of commercially available VEGF-reducing drugs, they can be ruled out as a suitable treatment for OHSS; therefore, researchers are looking for new medications to treat OHSS. This study is aimed at investigating the effects of cannabidiol (CBD) in an OHSS model and to evaluate its efficacy in modulating the angiogenesis pathway and VEGF gene expression. For this purpose, 32 female mice were randomly divided into four groups (eight mice per group): control group, group 2 with OHSS induction, group 3 receiving 32 nmol of dimethyl sulfoxide after OHSS induction, and group 4 receiving 30 mg/kg of CBD after OHSS induction. The animals' body weight, ovarian weight, vascular permeability (VP), and ovarian follicle count were measured, and the levels of VEGF gene and protein expression in the peritoneal fluid were assessed. Based on the results, CBD decreased the body and ovarian weights, VP, and corpus luteum number compared to the OHSS group (p < 0.05). The peritoneal VEGF gene and protein expression levels reduced in the CBD group compared to the OHSS group (p < 0.05). Also, CBD caused OHSS alleviation by suppressing VEGF expression and VP. Overall, CBD downregulated VEGF gene expression and improved VP in OHSS.

Inhibition of angiopoietin-1 (ANGPT1) affects vascular integrity in ovarian hyperstimulation syndrome (OHSS)

Ovarian hyperstimulation syndrome (OHSS) is a complication of ovarian stimulation with gonadotrophins following human chorionic gonadotrophin (hCG) administration. The relationship between hCG and OHSS is partly mediated via the production of angiogenic factors, such as vascular endothelial growth factor A (VEGFA) and angiopoietins (ANGPTs). Here, we investigated the effect of ANGPT1 inhibition on ovarian angiogenesis in follicular fluid (FF) from women at risk of OHSS, using the chorioallantoic membrane (CAM) of quail embryos as an experimental model. We also analysed cytoskeletal changes and endothelial junction protein expression induced by this FF in the presence or absence of an ANGPT1-neutralising antibody in endothelial cell cultures. The presence of this antibody restored the number of vascular branch points and integrin αvβ3 levels in the CAMs to control values. ANGPT1 inhibition in FF from OHSS patients also restored the levels of claudin-5, vascular endothelial cadherin and phosphorylated β-catenin and partially reversed actin redistribution in endothelial cells. Our findings suggest that ANGPT1 increases pathophysiological angiogenesis in patients at risk of OHSS by acting on tight and adherens junction proteins. Elucidating the mechanisms by which ANGPT1 regulates vascular development and cell–cell junctions in OHSS will contribute to identifying new therapeutic targets for the treatment of human diseases with aberrant vascular leakage.

Prevention and management of ovarian hyperstimulation syndrome

The Ovarian Hyperstimulation Syndrome (OHSS) represents one of the biggest nightmares of all physicians involved in Assisted Reproductive Technologies (ART). Every year, several hundreds of women are hospitalized and to date several deaths have been reported. The pivotal event in the development of OHSS is the disruption of capillary integrity that results in leakage of intravascular fluid and proteins into third space. On the molecular level, human chorionic godadotropin (HCG) either exogenous or endogenous, functions as the triggering point for the production of vascular endothelial growth factor (VEGF) that is the main mediator to increase permeability on the vascular bed. Spontaneous OHSS has also been reported, either due to inappropriate activation of a mutant FSH receptor or due to very high levels of HCG during pregnancy. The available evidence on the several preventive and therapeutic approaches with special attention to level 1 evidence when available is also presented. OHSS is a self-resolving condition and the main role of the physician is to correct and maintain the intravascular volume, to support renal function and respiration and prevent thrombotic events. An algorithm on the management of OHSS on an outpatient basis and in the hospital is based on the previous mentioned principles.

Human albumin does not prevent ovarian hyperstimulation syndrome in assisted reproductive technology program: a prospective randomized placebo-controlled double blind study

We aimed to clarify the efficiency of IV human albumin in the prevention of ovarian hyperstimulation syndrome (OHSS). We found that human albumin at the described strength does not seem to either prevent or reduce the incidence of severe OHSS in high risk patients undergoing intracytoplasmic sperm injection (ICSI).

Ovarian hyperstimulation syndrome

Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic complication that is associated with modern techniques for in vitro fertilization. Extensive efforts have been made to understand the pathophysiology and to improve the management of this entity. The severe and life-threatening forms of the ovarian hyperstimulation syndrome are still challenging for critical care physicians. This article reviews the pathogenesis, epidemiology, classification, clinical manifestations, and complications of these forms of OHSS. The different therapeutic options currently available are reviewed, and a stepwise approach for the management of these patients is provided.

Prevention and treatment of ovarian hyperstimulation syndrome

The ovarian hyperstimulation syndrome (OHSS) is a potentially fatal condition with a pathophysiology that is not clearly understood. A shift in fluid from the extravascular space occurs, thought to be induced by cytokines and/or vascular endothelial growth factor. Human chorionic gonadotrophin (hCG), exogenous or endogenous, seems to be the triggering mechanism, resulting in early and late development of the syndrome, respectively. The management of the syndrome is mainly symptomatic. Preventive strategies are being developed and constantly refined. Women at increased risk of OHSS need to be on the lowest possible dose of gonadotrophin with the aim of reducing the granulosa/luteal cell mass. Ultrasound and serum oestradiol (E2) measurements are, at present, the main methods used to identify and monitor those at risk during controlled ovarian hyperstimulation (COH). Withholding gonadotrophin stimulation (coasting), but continuing down-regulation, when a large number of follicles (greater than 20) and a rising serum oestradiol level are seen, is the most widely favoured and used preventive measure and the most cost effective. Management is symptomatic and aimed at achieving fluid balance, restoring plasma volume and improving renal function. This may be combined with an early resort to ascitic fluid aspiration, which will improve the feeling of wellbeing and may remove those agents responsible for the syndrome. Heparin, to prevent the risk of thromboembolism as a result of haemoconcentration, is important.

Ovarian hyperstimulation syndrome complicating a spontaneous singleton pregnancy: a case report

It has been known that most cases of ovarian hyperstimulation syndrome (OHSS) are associated with the use of exogenous gonadotropins to induce multiple ovulation. However, OHSS is infrequently associated with a spontaneous ovulatory cycle, usually in the case of multiple gestations, hypothyroidism, or polycystic ovarian syndrome. We report a case of severe OHSS in a spontaneously pregnant woman with no underlying disease.

The ovarian hyperstimulation syndrome

OBJECTIVE

To review the up-to-date literature concerning the pathogenesis of, risk factors for, prevention of, and therapy for the ovarian hyperstimulation syndrome, and to provide suggestions for management of this syndrome.

DESIGN

Literature review combined with on-site clinical experiences at the authors' institution of practice.

PATIENT(S)

Women who have risk factors for or manifest the ovarian hyperstimulation syndrome.

INTERVENTION(S)

Intravenous fluid management, thrombosis prevention techniques, paracentesis techniques, and critical care management protocols.

MAIN OUTCOME MEASURE(S)

Staging system of the ovarian hyperstimulation syndrome, criteria for outpatient versus hospitalization management, and indications for varying levels of interventional management.

RESULT(S)

The ovarian hyperstimulation syndrome, unique to the field of assisted reproductive technology, remains a largely elusive and unpredictable iatrogenic physiologic complication in the course of pharmacologic ovarian stimulation. Reliable information on risk factors, possible physiologic mechanisms, prevention techniques, and management is fortunately progressing, and overall advances are being made in this field. The present review is an attempt to summarize the modern literature regarding this syndrome and to use this current knowledge to provide a basis for acceptable management regimens.

CONCLUSION(S)

Ovarian hyperstimulation syndrome is a serious complication of assisted reproductive technology, with potential for critical morbidity and death. Physicians who prescribe medications known to be associated with this syndrome should be familiar with identifiable risk factors, means of prevention, and a system for staging and treating the disease and have a current knowledge base for putative models of pathogenesis.

Ovarian hyperstimulation syndrome

Ovarian hyperstimulation syndrome is an iatrogenic complication of assisted reproduction. In its most severe form, it is potentially fatal. The major clinical components are marked ovarian enlargement and increased capillary permeability leading to ascites, hydrothorax and pericardial effusion. Severe cases are associated with thromboembolic phenomena, respiratory distress and renal failure. The definitive pathophysiology is unknown. The available evidence would support a central role for inflammatory cytokines and angiogenic growth factors. Ultrasound examination and serum oestradiol values are currently used to predict patients at risk. The ideal treatment is prevention, but there has been only limited success. The main aims of treatment are to correct fluid imbalance, maintain renal perfusion and support the patient until the condition resolves. Drug therapy has a limited role, although anticytokine agents may prove useful.

Role of vascular endothelial cell growth factor in Ovarian Hyperstimulation Syndrome

Controlled ovarian hyperstimulation with gonadotropins is followed by Ovarian Hyperstimulation Syndrome (OHSS) in some women. An unidentified capillary permeability factor from the ovary has been implicated, and vascular endothelial cell growth/permeability factor (VEGF) is a candidate protein. Follicular fluids (FF) from 80 women who received hormonal induction for infertility were studied. FFs were grouped according to oocyte production, from group I (0-7 oocytes) through group IV (23-31 oocytes). Group IV was comprised of four women with the most severe symptoms of OHSS. Endothelial cell (EC) permeability induced by the individual FF was highly correlated to oocytes produced (r2 = 0.73, P < 0.001). Group IV FF stimulated a 63+/-4% greater permeability than FF from group I patients (P < 0. 01), reversed 98% by anti-VEGF antibody. Group IV fluids contained the VEGF165 isoform and significantly greater concentrations of VEGF as compared with group I (1,105+/-87 pg/ml vs. 353+/-28 pg/ml, P < 0. 05). Significant cytoskeletal rearrangement of F-actin into stress fibers and a destruction of ZO-1 tight junction protein alignment was caused by group IV FF, mediated in part by nitric oxide. These mechanisms, which lead to increased EC permeability, were reversed by the VEGF antibody. Our results indicate that VEGF is the FF factor responsible for increased vascular permeability, thereby contributing to the pathogenesis of OHSS.

Ovarian hyperstimulation syndrome: facts and fallacies

Severe or critical ovarian hyperstimulation syndrome (OHSS) is a serious complication of ovarian hyperstimulation for assisted reproduction techniques (ART). The syndrome is characterized by cystic enlargement of the ovaries and fluid shifts from the intravascular to the third space. The morbidity in OHSS is mainly determined by the hemodynamic changes caused by increased capillary permeability. The incidence of OHSS depends on definitions, risk factors, ovarian stimulation protocols, luteal support and conception. Currently, research on the pathogenesis of OHSS is focused on increased capillary permeability. Several theories are reviewed. Until the pathogenesis of OHSS becomes clear, treatment is restricted to supportive therapy. The various proposals for management of OHSS are discussed and, based on the available data, directions for the management of various grades of OHSS are summarized. However, prevention and early recognition are still the most important tools to handle OHSS. A flowchart with preventive measures for OHSS is presented derived from the available literature.

The pathogenesis of ovarian hyperstimulation syndrome: a continuing enigma

PURPOSE

Our purpose was to review the available literature concerning the pathogenesis of ovarian hyperstimulation syndrome and, in light of the most recent information, to attempt to provide further insight on this iatrogenic complication associated with the induction of ovulation.

METHODS

Published studies related to this topic were identified through a computerized bibliographic search.

CONCLUSIONS

The exact mechanism for the development of ovarian hyperstimulation syndrome is still obscure. It is well established that the syndrome is associated with the process of ovulation induced by either luteinizing hormone or human chorionic gonadotropin. Following ovulation, one or more substances produced by the ovary are liberated in excess, increasing capillary permeability, resulting in the clinical features of the syndrome. It may well be that the syndrome is not triggered by a single mechanism but by the production and secretion of several substances acting in concert. These may include prostaglandins, cytokines, the ovarian reninangiotensin system, vascular endothelial growth factor, and nitric oxide.

In controlled ovarian hyperstimulation, steroid production, oocyte retrieval, and pregnancy rate correlate with gene expression of vascular endothelial growth factor

PURPOSE

Whether the gene expression of vascular endothelial growth factor (VEGF) in human granulosa cells is a predictor of fertilization was evaluated in patients participating in an in vitro fertilization program.

METHODS

Fifty patients with normal ovaries who were participating in an in vitro fertilization program at the University of Milan, San Raffaele Scientific Institute, were included in the study. We correlated E2 and P serum levels on the day of oocyte collection, the number of follicles, oocytes collected, and fertilized, and pregnancies with mRNA for VEGF of luteinizing granulosa cells obtained at the time of oocyte retrieval.

RESULTS

Comparing E2 and P serum levels, the number of follicles, oocytes collected and fertilized, and pregnancies with gene expression for VEGF, we found a positive correlation. E2 and P serum levels were higher in patients with increased VEGF (P < 0.01). Furthermore, there were more follicles, oocytes collected and fertilized, and pregnancies in patients with maximum expression of VEGF, and the difference was statistically significant (P < 0.05).

CONCLUSIONS

Our results suggest that VEGF may be important for vascular development during follicular growth and luteal differentiation, oocyte maturation, and fertilization.

Expression of vascular endothelial growth factor in human luteinizing granulosa cells and its correlation with the response to controlled ovarian hyperstimulation

Ovulation induction represents one of the most important steps for the success of assisted reproductive technology (ART) procedures. To better understand the mechanisms that regulate follicle growth, oocyte maturation, and ovarian steroidogenesis, we investigated the correlations between vascular endothelial growth factor (VEGF) gene expression in human luteinizing granulosa cells, steroid production and oocyte retrieval in patients undergoing controlled ovarian hyperstimulation. We evaluated the messenger ribonucleic acid (mRNA) for VEGF in human luteinizing granulosa cells obtained at the time of oocyte retrieval from 24 women participating in an in vitro fertilization program at the Reproductive Endocrinology Center of our Department of Obstetrics and Gynecology. We found a positive linear correlation of VEGF mRNA with estradiol and progesterone serum levels at the day of oocyte retrieval (p < 0.05). Furthermore, VEGF mRNA expression was significantly higher in granulosa cells obtained from patients with an elevated number of oocytes and high fertilization rate (p < 0.05). Our data confirm that VEGF may play an important role in the regulation of vascular development during follicular growth and luteal differentiation.

Increased capillary permeability induced by human follicular fluid: a hypothesis for an ovarian origin of the hyperstimulation syndrome

OBJECTIVE

To examine the effect of follicular fluid (FF) and peritoneal fluid (PF) from patients undergoing assisted reproductive technology procedures on endothelial barrier function. This was determined in vitro by measuring the permeability of filter-grown bovine aortic endothelial cell monolayers to a permeability marker.

DESIGN

Endothelial cells obtained from bovine thoracic arotas were treated with collagenase solution and plated on millicell filters, on which they formed confluent monolayers. Flux rate was determined at 60 minutes by measuring the radioactive tracer (3H mannitol) permeating from the apical to the basolateral part of the filter. Fifty-eight samples of FF and PF, both from stimulated and natural cycles were analyzed and grouped according to the number of eggs retrieved. Follicular fluid and PF samples from natural cycles were used as controls.

RESULTS

There was an augmentation in the permeability rate of both FF and PF from patients undergoing controlled ovarian hyperstimulation (COH) who responded with an increasing number of eggs compared with controls (51% and 39%, respectively). When analyzing samples from patients who responded with a low number of oocytes, no significant increase was observed.

CONCLUSIONS

It is known that in OHSS, the increase in capillary permeability is related to the administration of gonadotropins, and is believed to be mediated by a vasoactive substance of ovarian origin. In this study, FF and PF from patients undergoing COH showed a significant increase in the permeability rate through endothelial cells in vitro. Based on these findings, it could be hypothesized that if the same events took place in vivo, the isolation of this factor from ovarian source could be of significant importance to elucidate the pathogenesis of OHSS.

Profound hypotension and sodium retention with the ovarian hyperstimulation syndrome

A 34-year-old woman developed profound hypotension and sodium retention following hormonal induction of ovulation. There was a transient response to infusion of albumin, but hypotension and hyponatremia persisted for 5 days. Nevertheless, acute renal failure did not develop. Available information indicates that this syndrome can occur with exogenous administration of gonadotrophic hormones or with a successful pregnancy.

The ascites in the ovarian hyperstimulation syndrome does not originate from the ovary

OBJECTIVE

To evaluate the direct ovarian contribution to ascites formation in the ovarian hyperstimulation syndrome (OHSS) in a rabbit model.

DESIGN

Prospective experimental study.

SETTING

Research center of a university teaching hospital.

PARTICIPANTS

New Zealand White rabbits.

INTERVENTIONS

Both ovaries of the rabbits in the experimental group were enclosed within a pouch developed from the surrounding peritoneum and mesosalpinx by microsurgery. Animals in the control group did not undergo any surgical intervention. Ovarian hyperstimulation was induced by alternate day equine chorionic gonadotropin and intermittent human chorionic gonadotropin (hCG).

MAIN OUTCOME MEASURES

Degree of ascites formation and the morphological and endocrinologic signs of ovarian hyperstimulation.

RESULTS

The serial plasma estradiol and progesterone levels, ovarian weights, and ascites response were not statistically different between the two groups.

CONCLUSIONS

Isolation of both ovaries from the peritoneal cavity does not prevent ascites formation in the OHSS. Increased transudation across extraovarian serosal surfaces contributes to ascites formation in OHSS.

Prostaglandins in the ovary and fallopian tube

More than 20 years following the recognition of a possible role for eicosanoids in ovarian function a physiological role for prostaglandins and/or leukotrienes in human ovulation, corpus luteum function and tubal motility remains to be demonstrated. With respect to ovarian function, the well-characterized preovulatory rise in eicosanoid production in animal species and humans, in conjunction with the large body of experimental evidence employing inhibitors of prostaglandin synthesis and replacement of individual prostaglandins, has provided strong evidence for a role in follicular rupture independent of other LH-mediated ovulatory events. The possible mechanism of prostaglandin-induced follicle rupture may involve stimulation of proteolytic activity via substances such as plasmin and PA; however, this is controversial. A role for prostaglandins in ovarian luteal function is well established in laboratory animals and large ruminant species, where PGF2 alpha derived from the uterus has been demonstrated to be the luteolytic factor. In humans, luteal function may be influenced by local intraovarian eicosanoid production, which has been suggested to involve the paracrine interaction of local ovarian hormones such as oxytocin, noradrenaline, insulin and IGFs, to name but a few. Several lines of evidence have also implicated prostaglandins as an aetiological factor in ovarian pathological states such as seen in the OHSS. However, the bulk of clinical experimental evidence to date has failed to support this contention. Prostaglandin production has likewise been well characterized in the fallopian tube in both humans and animal species. Whereas a role for prostaglandins in tubal transport has been demonstrated with animal species such as the rabbit, several studies have failed to define a similar function in humans. More recently, direct injections of prostaglandin analogues into the fallopian tube and the corpus luteum have been shown to be efficacious as a treatment for ectopic pregnancy. Whether the primary mechanism of action involves effects on tubal musculature or corpus luteum function, or is simply a local vascular effect, remains to be demonstrated. Therefore, although the physiological role for eicosanoids in ovarian and tubal function remains unclear, particularly in the human, an increasing body of recent evidence has suggested an important paracrine function for this class of cellular mediators whose interaction with other more recently characterized local ovarian factors has only begun to be recognized.

Ovarian hyperstimulation syndrome in novel reproductive technologies: prevention and treatment

OBJECTIVE

To overview the world literature on ovarian hyperstimulation syndrome (OHSS) and modes of prevention and treatment of OHSS.

STUDY SELECTION

All the pertinent literature on OHSS, its prevention, and strategies for treatment were reviewed.

PREVENTION

Key to prevention is proper identification of the population at risk, which includes women with either the hormonal or the morphological signs of polycystic ovarian disease, high serum estradiol (E2) before human chorionic gonadotropin (hCG) administration (E2 greater than 4,000 pg/mL), multiple follicular response (greater than 35), younger age, and lean habitus. When a high risk situation is recognized, ovulatory dose of hCG may be reduced, avoided (with cycle cancellation), or substituted by gonadotropin-releasing hormone or its agonist. Luteal support with hCG is to be bypassed. To minimize risk of OHSS, endogenous pregnancy-drived hCG may be eluded by judicious cryopreservation of all embryos. Last, follicular aspiration will allow higher levels of E2 and larger number of follicles to be matured with lesser risk of OHSS than conventional ovulation induction without follicular aspiration.

TREATMENT

In-house for the severe and intensive care for the critical form. Meticulous fluid and electrolyte balance using both crystalloids and colloids (albumin) until hemoconcentration abates. Paracentesis is indicated for tight ascites, deteriorating kidney functions, and symptomatic relief. Diuretics may be prudently used once hemodilution is achieved. Dopamine drip may be used as a renal rescue, whereas heparin is indicated for thromboembolic phenomena and surgery reserved for abdominal catastrophies. Therapeutic interruption of an early gestation may be lifesaving when all other measures have failed.

CONCLUSIONS

Although severe and critical OHSS may not be completely avoided, early recognition of high-risk factors, judicious prevention schemes, and treatment strategies should reduce the complication and long-term sequelae of this iatrogenic syndrome.

Accidental hyperstimulation during ovulation induction

Clinical hyperstimulation is the most serious complication of ovulation induction, occurring in approximately 3% of cases (0.8% in the severe form). Paradoxically, it seems to be rare following in vitro fertilization, probably because all the follicles are aspirated. High-risk patients are those with polycystic ovarian disease, hyperprolactinaemia and hypothyroidism. All forms of ovulation induction have been implicated. Use of LHRH agonists have not reduced the incidence of hyperstimulation and they may even have increased it. An ongoing pregnancy seems to predispose to the occurrence of hyperstimulation, due to the secretion of hCG. Clinically, three stages of hyperstimulation have been described by the WHO (mild, moderate and severe). The pathophysiology is not completely understood, although prostaglandins, histamines and, especially, the ovarian renin-angiotensin system may be involved. Local ovarian complications and thromboembolic complications have also occurred. The treatment of severe hyperstimulation is both symptomatic (fluid replacement, aspiration of effusions, moderate sodium and water restriction, small doses of diuretics) and specific (corticosteroids, aspiration of ovarian cysts, even voluntary interruption of pregnancy in the most serious forms). If the hyperstimulation occurs in the absence of pregnancy, antihistamines or antiprostaglandins can be given. Prevention is exceedingly important. This can be helped by recognition of polycystic ovarian disease and stimulation of these cases by clomiphene citrate or pure FSH associated, for use in in vitro fertilization, with prolonged desensitization using LHRH agonists. Daily ultrasound and hormonal monitoring of ovulation induction is required. When there is excessive response to stimulation, it is prudent not to induce ovulation with hCG or, alternatively, to aspirate all the follicles and freeze the embryos obtained without giving further injections of hCG in the luteal phase. Clinical ovarian hyperstimulation is the classic form of iatrogenic disorder and is the most important complication of ovulation induction treatments, since it can be life-threatening in its most severe form. In this chapter we review current knowledge concerning the frequency, factors associated with its occurrence, clinical aspects, physiopathological mechanisms and, finally, the possibilities for treatment and prevention.

[The syndrome of ovarian hyperstimulation]

The ovarian hyperstimulation syndrome (SHO) can be defined as an iatrogenic pathology induced by active substances administered for controlling follicular maturation and ovulation. The etiology, the physiopathology, the diagnostic and therapeutic methods available are discussed. A theoretical model, based on clinical data, allows identification of a set of criteria which should help determining prospectively the chances of development of such a pathology.

Relationship of gonadotropin-releasing hormone, danazol, and prostaglandin blockade to ovarian enlargement and ascites formation of the ovarian hyperstimulation syndrome in the rabbit

The effects of pharmacologic doses of gonadotropin-releasing hormone, danazol, and indomethacin on the clinical and endocrinologic features of the ovarian hyperstimulation syndrome were studied in the rabbit. The ovarian hyperstimulation syndrome was induced with Pergonal (75 IU of follicle-stimulating hormone and 75 IU of luteinizing hormone) and a follicle-stimulating hormone-dominant gonadotropin preparation (85 IU of follicle-stimulating hormone and 53 IU of luteinizing hormone). None of the three agents tested were effective in suppressing the ovarian enlargement and ascites formation in these animals. Ascites developed despite quite significant variations in plasma and intraovarian sex steroid hormone and intraovarian prostaglandin F levels induced by danazol and indomethacin. Ascites develops in hyperstimulated women in association with both follicular and luteal hyperstimulation. In contrast, the ascites response in the hyperstimulated rabbit develops in the presence of follicular hyperstimulation alone without a significant degree of luteal hyperstimulation.