Ovarian hyperstimulation syndrome: a review of pathophysiology

Ovarian Hyperstimulation Syndrome (OHSS): A Narrative Review and Legal Implications

BACKGROUND

Infertility is a highly meaningful issue with potentially life-changing consequences, and its incidence has been growing worldwide. Assisted reproductive technology (ART) has made giant strides in terms of treating many infertility conditions, despite the risk of developing ovarian hyperstimulation syndrome (OHSS), a potentially life-threatening complication.

METHODS

This narrative review draws upon scientific articles found in the PubMed database. The search spanned the 1990-2024 period. Search strings used included "OHSS" or "ovarian hyperstimulation" and "IVF" and "GnRH" and "hCG"; 1098 results were retrieved and were ultimately narrowed down to 111 suitable sources, i.e., relevant articles dealing with the condition's underlying dynamics, management pathways, and evidence-based criteria and guidelines, crucial both from a clinical perspective and from the standpoint of medicolegal tenability.

RESULTS

The following features constitute OHSS risk factors: young age, low body weight, and polycystic ovarian syndrome (PCOS), among others. GnRH antagonist can substantially lower the risk of severe OHSS, compared to the long protocol with a gonadotropin-releasing hormone (GnRH) agonist. However, a mild or moderate form of OHSS is also possible if the antagonist protocol is used, especially when hCG is used for the final maturation of oocytes. For women at risk of OHSS, GnRH agonist trigger and the freeze-all strategy is advisable. OHSS is one of the most frequent complications, with a 30% rate in IVF cycles.

CONCLUSION

Providing effective care for OHSS patients begins with early diagnosis, while also evaluating for comorbidities and complications. In addition to that, we should pay more attention to the psychological component of this complication and of infertility as a whole. Compliance with guidelines and evidence-based best practices is essential for medicolegal tenability.

Prevention of moderate and severe ovarian hyperstimulation syndrome: a guideline

Ovarian hyperstimulation syndrome is a serious complication associated with assisted reproductive technology. This systematic review aims to identify who is at high risk for developing ovarian hyperstimulation syndrome, along with evidence-based strategies to prevent it and replaces the document of the same name last published in 2016.

Diagnostic Complexities in a Case of Ovarian Hyperstimulation Syndrome Presented Solely as a Unilateral Massive Hydrothorax

To describe a rare case of unilateral massive hydrothorax after controlled ovarian stimulation for IVF and to analyze the diagnostic complexities in a patient lacking both risk factors and typical features of ovarian hyperstimulation syndrome (OHSS). We present a case of a 35-year-old woman suffering from primary infertility due to a severe male factor. Admitted to hospital for dyspnea, the patient initially underwent a thoracentesis. Later, due to the recurrence of massive hydrothorax, permanent pleural drainage was placed. Recognized as a severe manifestation of the OHSS, it was treated by pleural drainage, hydration, albumin perfusion, and management of the intercurrent pregnancy, up to improvement in clinical and hematological laboratory parameters and resolution of pleural effusion and respiratory symptoms. A total of 42 l of pleural fluid was drained during the 40 days of hospitalization. Since the pathogenesis of isolated acute hydrothorax in ovarian stimulation probably lies in the presence of anatomical defects of the diaphragm, this may justify that the relationship between this pathology and the OHSS risk factors may be less close. Massive pleural effusion may exceptionally be the only clinical presentation of OHSS. A high index of suspicion is necessary to make the correct diagnosis and to promptly administer treatment.

Patients who failed to conceive following an in vitro fertilization cycle can be clustered into different failure causes using gene expression hierarchical analysis†

The patient's response to an IVF stimulation protocol is highly variable and thus difficult to predict. When a cycle fails, there are often no apparent or obvious reasons to explain the failure. Having clues on what went wrong during stimulation could serve as a basis to improve and personalize the next protocol. This exploratory study aimed to investigate if it is possible to distinguish different failure causes or different follicular responses in a population of nonpregnant IVF patients. Using qRT-PCR, we analyzed a panel of genes indicative of different failure causes in patients who did not achieve pregnancy following an IVF cycle. For each patient, a pool of follicular cells from all aspirated follicles was used as a sample which gives a global picture of the patient's ovary and not a specific picture of each follicle. We performed hierarchical clustering analysis to split the patients according to the gene expression pattern. Hierarchical analysis showed that the population of nonpregnant IVF patients could be divided into three clusters. Gene expression was significantly different, and each cluster displayed a particular gene expression pattern. Follicular cells from patients in clusters 1, 2 and 3 displayed respectively a pattern of gene expression related to large incompetent follicles with a higher apoptosis (over matured), to follicles not ready to ovulate (under mature) and to an excess of inflammation with no visible symptoms. This study reinforces the idea that women often have different response to the same protocol and would benefit from more personalized treatments.

Application of non-invasive detection of peripheral vascular dysfunction in ovarian hyperstimulation syndrome (OHSS): A pilot study of clinical relevance

OBJECTIVE

The current study tested the hypothesis that vascular endothelial function, as reflected by the reactive hyperemia index (RHI), and biochemical factors, including VEGF, TNFα, CRP, inhibin A, and inhibin B, were involved in the pathogenesis of ovarian hyperstimulation syndrome (OHSS).

MATERIALS AND METHODS

This study was conducted between June 2010 and June 2012, enrolling 15 patients with OHSS and 6 healthy control subjects <45 years of age. Detailed clinical parameters were reviewed, including serum VEGF, TNFα, CRP, inhibin A, inhibin B, and hematocrit. RHI assessed by novel automatic peripheral arterial tonography was used to evaluate the vascular endothelial function.

RESULTS

Twenty-one subjects were evaluated. There was no significant difference between patients with OHSS and control subjects with respect to VEGF, TNFα, CRP, inhibin A and inhibin B. The RHI was not significantly different between patients with OHSS and control subjects (mean, 1.8 ± 0.4 vs. 1.7 ± 0.2). The hematocrit was significantly different between patients with OHSS and control subjects.

CONCLUSIONS

Our preliminary data did not reveal direct evidence of vascular endothelial dysfunction in patients with OHSS. To identify whether RHI could reflect vascular endothelial dysfunction in patients with OHSS, more cases with different severities of OHSS should be recruited in the future study.

Ovarian hyperstimulation syndrome: A review for emergency clinicians

INTRODUCTION

A great deal of literature has recently evaluated the prevention and management of ovarian hyperstimulation syndrome (OHSS) in the outpatient setting, but there remains a dearth of research evaluating OHSS in the emergency department (ED) and its management.

OBJECTIVE

This narrative review evaluates the underlying pathophysiology and clinical manifestations of OHSS and discusses approaches to patient care in the ED based on current literature.

DISCUSSION

OHSS is an iatrogenic complication caused by an excessive response to controlled ovarian stimulation during assisted reproductive cycles (ART). OHSS complicates up to 30% of ART cycles, and many of these patients seek initial care in the ED. Risk factors for the development of OHSS include age < 35, history of polycystic ovarian syndrome or previous OHSS, and pregnancy. Emergency physicians will be faced with several complications including ascites, abdominal compartment syndrome, renal dysfunction, acute respiratory distress syndrome, thromboembolic disease, and hemodynamic instability. Critical patients should be evaluated in the resuscitation bay, and consultation with the primary obstetrics/gynecology team is needed, which improves patient outcomes. This review provides several guiding principles for management of OHSS and associated complications.

CONCLUSIONS

OHSS occurs in up to 30% of IVF cycles and carries a high morbidity. Effective care of the OHSS patient begins with early diagnosis while evaluating for other diseases and complications. Understanding these complications and an approach to the management of OHSS is essential to optimizing patient care.

Gene expression analysis of follicular cells revealed inflammation as a potential IVF failure cause

PURPOSE

Hormonal stimulation prior to IVF influences the ovarian environment and therefore impacts oocytes and subsequent embryo quality. Not every patient has the same response to the same treatment and many fail for unknown reasons. Knowing why a cycle has failed and how the follicles were affected would allow clinicians to adapt the treatment accordingly and improve success rate. This study examines the hypothesis that transcriptomic analysis of follicular cells from failed IVF cycles reveals potential reasons for failure and provides new information on the physiological mechanisms related to IVF failure.

METHODS

Follicular cells (granulosa cells) were obtained from IVF patients of four Canadian fertility clinics. Using microarray analysis, patients that did not become pregnant following the IVF cycle were compared to those that did. Functional analysis was performed using ingenuity pathway analysis and qRT-PCR was used to validate the microarray results in a larger cohort of patients.

RESULTS

The microarray showed 165 differentially expressed genes (DEGs) in the negative group compared to the pregnancy group. DEGs include many pro-inflammatory cytokines and other factors related to inflammation, suggesting that this process might be altered when IVF fails. Overexpression of several factors, some of which act upstream from vascular endothelial growth factor (VEGF), also indicates increased permeability and vasodilation. Some DEGs were related to abnormal differentiation and increased apoptosis.

CONCLUSIONS

Our results suggest that failure to conceive following IVF cycles could be associated with an imbalance between pro-inflammatory and anti-inflammatory mediators. The findings of this study identify potential failure causes and pathways for further investigation. Stimulatory protocols personalized according to patient response could improve the chances of later success.

Higher melatonin in the follicle fluid and MT2 expression in the granulosa cells contribute to the OHSS occurrence

BACKGROUND

Ovarian hyperstimulation syndrome (OHSS) is a common and severe complication for patients undergoing IVF/ICSI-ET. Melatonin widely participates in the regulation of female reproductive endocrine activity. However, whether melatonin participates in the progression of OHSS is largely unknown. This study aims to identify the predictive value of follicular fluid (FF) melatonin for OHSS establishment and the underlying mechanism.

METHODS

All participants of this case-control study were enrolled at the Reproductive Medicine Center located in the First Affiliated Hospital of Zhengzhou University in China from January to October in 2017. Quantitative real-time PCR and western blot were used to examine the mRNA and protein levels. Primary granulosa cells were extracted and cultured for in vitro studies. Melatonin concentration was measured by ELISA. Logistic analysis and receiver-operating characteristic (ROC) curves were used to evaluate the predicting value of melatonin on OHSS occurrence.

MAIN OUTCOME MEASURES

The expression level of melatonin receptor 2 (MT2), P450 aromatase cytochrome (aromatase), vascular endothelial growth factor (VEGF), and inducible nitric oxide synthase (iNOS) mRNA in human primary granulosa cells. The concentration of melatonin in FF. The predicting value of melatonin on OHSS and the cut-off value of the prediction.

RESULTS

FF melatonin concentrations were significantly higher in patients with OHSS compared to non-OHSS group (35.94 ± 10.18 ng/mL vs 23.93 ± 10.94 ng/mL, p<0.001). The expression of MT2 mRNA (p = 0.0459) and protein in granulosa cells was also significantly higher in the OHSS group. When using a cut-off level of 27.52 ng/ml, the sensitivity and specificity of FF melatonin to predict OHSS was 84.6 and 74.0%, respectively (p < 0.0001). We also found that melatonin could up-regulates aromatase mRNA, VEGF mRNA expression and down-regulates iNOS mRNA expression in the granulosa cells.

CONCLUSION

OHSS patients have higher melatonin in the FF as well as higher MT2 expression in the granulosa cells. The melatonin in FF might be used as an effective predictor for the occurrence of OHSS.

Acute Kidney Injury Due to Ovarian Hyperstimulation Syndrome

Ovarian hyperstimulation syndrome (OHSS) is a complication of assisted reproductive treatments such as in vitro fertilization (IVF). The pathophysiology of severe OHSS includes a humorally mediated capillary leak syndrome that is predominantly centered on the intra-abdominal space. Severe OHSS is frequently complicated by acute kidney injury (AKI), which can be due to any of a variety of mechanisms, each requiring a different management strategy. Mechanisms of AKI in severe OHSS include intravascular volume depletion, kidney edema due to capillary leak, intra-abdominal hypertension or compartment syndrome, and obstructive uropathy due to ovarian enlargement. We present a teaching case of severe OHSS complicated by AKI in a woman with underlying stage 4 chronic kidney disease. She had been undergoing IVF with plans to subsequently use a gestational carrier (surrogate) for pregnancy. We use this case to review the presentation and pathophysiology of OHSS complicated by AKI. In addition, we review the management of AKI in OHSS, in particular, the role of paracentesis and/or culdocentesis to manage tense ascites. Last, we highlight that similar cases may occur more frequently in the future given that IVF with subsequent use of a gestational carrier is increasingly being used for patients with comorbid conditions that can be exacerbated by pregnancy, such as advanced chronic kidney disease.

A novel oocyte maturation trigger using 1500 IU of human chorionic gonadotropin plus 450 IU of follicle-stimulating hormone may decrease ovarian hyperstimulation syndrome across all in vitro fertilization stimulation protocols

PURPOSE

Modification of the trigger used to induce final oocyte maturation in in vitro fertilization (IVF) is a major strategy used to reduce the risk of ovarian hyperstimulation syndrome (OHSS). A novel trigger composed of 1500 IU of human chorionic gonadotropin (hCG) plus 450 IU of follicle-stimulating hormone (FSH) has been developed to reduce OHSS risk. This study compares outcomes of the novel trigger to conventional triggers used in high-risk OHSS patients undergoing IVF.

METHODS

In this retrospective cohort study, IVF cycles at high risk for OHSS based on a serum estradiol > 5000 pg/ml on trigger day conducted between January 2008 and February 2016 were evaluated. Oocyte maturation was induced with the novel trigger (1500 IU hCG plus 450 IU FSH) or a conventional trigger [3300 IU hCG, gonadotropin-releasing hormone agonist (GnRHa) alone, or GnRHa plus 1500 IU hCG]. IVF cycle outcomes were compared. Trigger strategies were examined for associations with OHSS development using logistic regression.

RESULTS

Among 298 eligible IVF cycles identified, there were no differences in oocyte maturation, fertilization, embryo quality, or pregnancy outcomes among all triggers. After adjusting for serum estradiol level and number of follicles, the novel trigger was associated with lower odds of OHSS symptom development compared to the 3300 IU hCG and GnRHa plus hCG 1500 IU triggers (p = 0.007 and 0.04, respectively).

CONCLUSIONS

This study suggests that 1500 IU hCG plus 450 IU FSH may be associated with decreased OHSS symptoms compared to conventional triggers, while producing similar IVF and pregnancy outcomes. More important, this novel trigger may provide a superior alternative in down-regulated cycles and in patients with hypothalamic dysfunction where GnRHa triggers cannot be utilized.

Prevention and treatment of moderate and severe ovarian hyperstimulation syndrome: a guideline

Ovarian hyperstimulation syndrome (OHSS) is an uncommon but serious complication associated with assisted reproductive technology (ART). This systematic review aims to identify who is at high risk, how to prevent OHSS, and the treatment for existing OHSS.

Targeted single molecule sequencing methodology for ovarian hyperstimulation syndrome

Background

One of the most significant issues surrounding next generation sequencing is the cost and the difficulty assembling short read lengths. Targeted capture enrichment of longer fragments using single molecule sequencing (SMS) is expected to improve both sequence assembly and base-call accuracy but, at present, there are very few examples of successful application of these technologic advances in translational research and clinical testing. We developed a targeted single molecule sequencing (T-SMS) panel for genes implicated in ovarian response to controlled ovarian hyperstimulation (COH) for infertility.

Results

Target enrichment was carried out using droplet-base multiplex polymerase chain reaction (PCR) technology (RainDance®) designed to yield amplicons averaging 1 kb fragment size from candidate 44 loci (99.8% unique base-pair coverage). The total targeted sequence was 3.18 Mb per sample. SMS was carried out using single molecule, real-time DNA sequencing (SMRT® Pacific Biosciences®), average raw read length = 1178 nucleotides, 5% of the amplicons >6000 nucleotides). After filtering with circular consensus (CCS) reads, the mean read length was 3200 nucleotides (97% CCS accuracy). Primary data analyses, alignment and filtering utilized the Pacific Biosciences® SMRT portal. Secondary analysis was conducted using the Genome Analysis Toolkit for SNP discovery l and wANNOVAR for functional analysis of variants. Filtered functional variants 18 of 19 (94.7%) were further confirmed using conventional Sanger sequencing. CCS reads were able to accurately detect zygosity. Coverage within GC rich regions (i.e.VEGFR; 72% GC rich) was achieved by capturing long genomic DNA (gDNA) fragments and reading into regions that flank the capture regions. As proof of concept, a non-synonymous LHCGR variant captured in two severe OHSS cases, and verified by conventional sequencing.

Conclusions

Combining emulsion PCR-generated 1 kb amplicons and SMRT DNA sequencing permitted greater depth of coverage for T-SMS and facilitated easier sequence assembly. To the best of our knowledge, this is the first report combining emulsion PCR and T-SMS for long reads using human DNA samples, and NGS panel designed for biomarker discovery in OHSS.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1451-2) contains supplementary material, which is available to authorized users.

The role of osmoregulation in the pathophysiology and management of severe ovarian hyperstimulation syndrome

Severe ovarian hyperstimulation syndrome (OHSS), with an incidence of 1-2% of superovulation cycles, remains one of the most important complications of gonadotrophin use in assisted reproductive technologies because of its associated morbidity and rarely, mortality. Despite the wealth of scientific and clinical interest that this iatrogenic complication has generated, its pathophysiology is still not adequately elucidated and its management has thus remained empirical. Disorders of salt and water balance are two very important features that have been reported during severe OHSS. Some of the clinical and biochemical changes resulting from this disorder of salt and water balance are similar to those previously reported in pregnancy and liver cirrhosis. The pathophysiology of these clinical changes has been explained in part in pregnancy and liver cirrhosis by changes in osmoregulation function. It is this similarity in the clinical and biochemical changes in OHSS, pregnancy and liver cirrhosis that has prompted the investigation of the role of osmoregulation function in the pathophysiology of OHSS. The current article has been written to provide further details in support of recent excellent articles and guidelines, highlighting the physiological basis and rationale governing some aspects of, and the role of osmoregulation in the management of the OHSS syndrome.

Association between the luteinizing hormone/chorionic gonadotropin receptor (LHCGR) rs4073366 polymorphism and ovarian hyperstimulation syndrome during controlled ovarian hyperstimulation

BACKGROUND

The aim of this study was to determine the relationship between a purported luteinizing hormone/chorionic gonadotropin (LHCGR) high function polymorphism (rs4539842/insLQ) and outcome to controlled ovarian hyperstimulation (COH).

METHODS

This was a prospective study of 172 patients undergoing COH at the Fertility and IVF Center at GWU. DNA was isolated from blood samples and a region encompassing the insLQ polymorphism was sequenced. We also investigated a polymorphism (rs4073366 G > C) that was 142 bp from insLQ. The association of the insLQ and rs4073366 alleles and outcome to COH (number of mature follicles, estradiol level on day of human chorionic gonadotropin (hCG) administration, the number of eggs retrieved and ovarian hyperstimulation syndrome (OHSS)) was determined.

RESULTS

Increasing age and higher day 3 (basal) FSH levels were significantly associated with poorer response to COH. We found that both insLQ and rs4073366 were in linkage disequilibrium (LD) and no patients were homozygous for both recessive alleles (insLQ/insLQ; C/C). The insLQ variant was not significantly associated with any of the main outcomes to COH. Carrier status for the rs4073366 C variant was associated (P = 0.033) with an increased risk (OR 2.95, 95% CI = 1.09-7.96) of developing OHSS.

CONCLUSIONS

While age and day 3 FSH levels were predictive of outcome, we found no association between insLQ and patient response to COH. Interestingly, rs4073366 C variant carrier status was associated with OHSS risk. To the best of our knowledge, this is the first report suggesting that LHCGR genetic variation might function in patient risk for OHSS.

Ultrasound evaluation of gynecologic causes of pelvic pain

Ultrasound should be considered the first-line imaging modality of choice in women presenting with acute or chronic pelvic pain of suspected gynecologic or obstetric origin because many, if not most, gynecologic/obstetric causes of pelvic pain are easily diagnosed on ultrasound examination. Since the clinical presentation of gynecologic causes of pelvic pain overlaps with gastrointestinal and genitourinary pathology, referral to CT or MRI, especially in pregnant patients, should be considered if the US examination is nondiagnostic.

New insights of osmoregulatory system changes in ovarian hyperstimulation syndrome

This study evaluated the osmoregulatory system changes in 39 patients with severe ovarian hyperstimulation syndrome. Plasma osmolality (Posm) less or more than 280 mOsm/kg body weight were associated with inappropriate antidiuretic hormone secretion syndrome and hypovolemia, respectively.

Miscarriage and clinical correlates of leukocyte count in patients with ovarian hyperstimulation syndrome

SUMMARY

This study was conducted to determine the pregnancy outcome in women with ovarian hyperstimulation syndrome and leukocytosis. From a total of 944 women who underwent IVF-ET, 89 (9.4%) developed OHSS, of whom 67 underwent embryo transfer. The criteria of the study were met by 53 women and underwent WBC count and haematological, hormonal and biochemical tests were performed on the day of HCG administration. Statistical comparison was made between women with a WBC count of >15,000 and those with a WBC count of <15,000. Patients with WBC count of >15,000 at the time of HCG administration (n = 24) had significantly increased rate of early pregnancy loss than women who had WBC count of <15,000 (n = 29). No other blood, chemical and hormonal parameters were different between the two groups. It is concluded that women with ovarian hyperstimulation syndrome in an IVF-ET cycle are more likely to miscarry if they have a WBC count of >15,000 on the day of HCG administration.

The ovarian hyperstimulation syndrome

Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic complication induced by exogenous administration of substances that are used to stimulate follicular growth and ovulation. There has only been one reported incidence of a spontaneous occurrence of OHSS and that was in 1992. The crucial event in the development of the syndrome is the administration of human chorionic gonadotropin (HCG), although several studies have reported the onset of OHSS after gonadotropin stimulation despite withholding HCG. OHSS is represented by a broad spectrum of clinical and laboratory manifestations which, in the severest form, can induce a life-threatening condition.

Ovarian Hyperstimulation Syndrome with pleural effusion: a case report

Background

To report a case of severe ovarian hyperstimulation syndrome (OHSS) with right pleural effusion following controlled ovarian hyperstimulation.

Case presentation

A 24-year-old woman had severe OHSS as a complication of gonadotropin stimulation. The clinical picture showed enlarged ovaries, massive ascites, pleural effusion, abdominal pain, and dyspnea. Beside the medical treatment, abdominal paracentesis for the drainage of the massive ascites and tube thoracostomy were performed, resulting in expansion of the lung.

Conclusion

Physicians can reduce the risk of OHSS by monitoring gonadotropin therapy and by withholding human chorionic gonadotropin medication. In in vitro fertilization protocols it can be advantageous to postpone the embryo transfer by freezing the embryos. Placement of a chest tube is a safe and efficient method for the treatment of pleural effusion.

Growth hormone and in vitro maturation of rhesus macaque oocytes and subsequent embryo development

PURPOSE

The objective of this study was to use a nonhuman primate model to examine the effects of growth hormone (GH) on oocyte in vitro maturation (IVM).

METHODS

Immunocytochemistry confirmed the presence of GH receptors in rhesus cumulus oocyte complexes and the cytoplasm of embryonic blastomeres. Recombinant human GH (r-hGH) was added to IVM medium and cumulus expansion, nuclear maturation, cytoplasmic maturation and embryo development were analyzed.

RESULTS

Cumulus expansion was highest in the presence of 1 and 10 ng/ml r-hGH. The addition of r-hGH during IVM increased the percentage of embryos progressing to at least the 9-16 cell stage. In a separate study, 100 ng/ml r-hGH was supplemented to IVM and embryo culture medium and no effect was observed.

CONCLUSIONS

The presence of GH receptors along with increased cumulus expansion and embryos progressing to the 9-16 cell stage supports the hypothesis that r-hGH may be involved in oocyte maturation.

Elevated oestradiol concentrations are not associated with increased first trimester miscarriage rates of singleton gestations conceived by assisted conception treatment

The study evaluated the impact of elevated oestradiol concentrations on pregnancy loss during the first trimester in singleton gestations conceived via ovarian stimulation and intracytoplasmic sperm injection (ICSI). Following determination of oestradiol concentrations during 6478 ICSI cycles, patients were assorted by oestradiol percentile. Hyper-responders were defined as patients having peak oestradiol concentrations over the 90th percentile (>4200 pg/ml, 685 cycles), moderate responders were defined as patients having peak oestradiol concentrations between the 75th and 90th percentiles (3250-4200 pg/ml, 958 cycles) and normal responders were defined as patients having peak oestradiol concentrations between the 25th and 75th percentiles (1350-3250 pg/ml, 3325 cycles). The relationship between first trimester miscarriage rates and oestradiol percentiles was analysed in 1184 singleton gestations. Pregnancy rate was significantly lower in normal responders (54.4%) than in moderate (58.8%, P = 0.02) and hyper-responders (60.9%, P = 0.003), but there were no intergroup differences in miscarriage rate (19.6%, 17.1%, and 16.8%, respectively). Although women with severe ovarian hyperstimulation syndrome had a miscarriage rate of 40%, this rate did not differ significantly from the miscarriage rates of the other groups. The findings suggest that high oestradiol concentrations during ovarian stimulation do not expose singleton pregnancies to an increased risk of miscarriage during the first trimester.

Age dependent assessment of TFPI levels in follicular fluid of women undergoing IVF

BACKGROUND

Tissue factor pathway inhibitor (TFPI) is a multivalent Kunitz-type serine proteinase inhibitor which plays a central role in the extrinsic pathway of blood coagulation. A significant role of TFPI for the follicular development has been discussed in recent studies, and thrombotic complications during IVF procedure are a common problem. To elucidate the pathophysiological mechanisms underlying these problems, we have measured TFPI levels in human follicular fluid (hFF) of women undergoing in vitro fertilisation (IVF).

METHODS

Total TFPI concentrations were determined in hFF of 28 women undergoing IVF treatment, 6 of whom developed an ovarian hyperstimulation syndrome (OHSS).

RESULTS AND CONCLUSIONS

This is the first study to demonstrate an age-dependance of TFPI concentrations in hFF. Additionally, TFPI levels in hFF of women developing OHSS were determined as 323+/-66.8 ng/mL (mean+/-SD) in comparison with 279+/-137 ng/mL for non-OHSS patients. Our findings demonstrate that, unlike the decreased TFPI levels found in OHSS patients' blood, there is no statistically significant difference in hFF TFPI levels between OHSS and non-OHSS patients. Furthermore, we could show that the outcome of the IVF procedure is not correlated with TFPI levels in hFF.

Low-molecular-weight dextran infusion is more effective for the treatment of hemoconcentration due to severe ovarian hyperstimulation syndrome than human albumin infusion

The most severe complication of ovarian hyperstimulation syndrome (OHSS) is thromboembolism, which is related to hemoconcentration. Dextran 40 infusion has greater effectiveness for the treatment of hemoconcentration due to OHSS than does human albumin infusion.

Hypercoagulability, high tissue factor and low tissue factor pathway inhibitor levels in severe ovarian hyperstimulation syndrome: possible association with clinical outcome

During ovarian gonadotrophin stimulation for ovulation induction or in vitro fertilization, a clinical severe ovarian hyperstimulation syndrome (OHSS) may occur. Only few studies have investigated the mechanism responsible for the alterations of the haemostatic system in women affected by severe OHSS. The aim of the present study was to investigate the correlation between the magnitude of ovarian stimulation and the increase in fibrin formation and degradation in severe OHSS. Twenty-five patients (age range 23-43 years) who were hospitalized for severe OHSS, 25 women undergoing in vitro fertilization who did not develop OHSS (case-control group) and 25 healthy age-matched women (healthy control group) were investigated. On the day of admission a number of haemostatic markers, including D-dimer, thrombin-antithrombin complexes (TAT), prothrombin fragment 1 + 2 (F1 + 2), plasmin-antiplasmin complexes (PAP), tissue factor (TF), tissue factor pathway inhibitor (TFPI) and von Willebrand factor antigen (vWF), were examined. In patients with severe OHSS, TF, D-dimer, TAT, F1 + 2, PAP and vWF antigen plasma levels were significantly higher than those observed both in the case-control group and in healthy controls, whereas TFPI levels were significantly lower (P < 0.005) with respect to both case-controls and healthy controls. D-Dimer levels were related with serum oestradiol levels and oocyte number recovered (r = 0.45, P < 0.001 and r = 0.47, P < 0.001, respectively). D-Dimer and TAT levels were significantly (P < 0.05 and P < 0.005, respectively) higher in OHSS patients with unsuccessful pregnancy outcome (D-dimer, 226.5, 56-1449 ng/ml; TAT, 19.8, 3.1-82.6 microg/l) with respect to those with successful outcome of pregnancy (D-dimer, 145, 29-330 ng/ml; TAT, 5.0, 1.0-19.6 microg/l). Our data indicate that a marked hypercoagulability with alterations of TF and TFPI levels is detectable in patients with severe OHSS and that it is related to the clinical outcome.

Aromatase inhibitors for the treatment of infertility

Ovarian stimulation during infertility treatment is used either alone or in conjunction with intrauterine insemination and assisted reproductive technologies. At the present time, the two main medications used for ovarian stimulation include an oral antioestrogen, clomiphene citrate and injectable gonadotrophins. In spite of the high ovulation rate, the use of clomiphene citrate is associated with adverse side effects and low pregnancy rates. In clomiphene citrate failures, gonadotrophin injections are generally the next treatment option but, especially in polycystic ovarian syndrome, are associated with increased risk of severe ovarian hyperstimulation syndrome and high multiple pregnancies. Therefore, an effective oral treatment that could be used without risk of ovarian hyperstimulation syndrome and with minimal monitoring is preferred. It was hypothesised that aromatase inhibitors can be administered early in the follicular phase to induce ovulation by releasing the hypothalamus and/or pituitary from oestrogen negative feedback. The success of aromatase inhibitors in induction and augmentation of ovulation has been reported. In addition, increased intraovarian androgen levels may synergise with central effects of decreased oestrogen to enhance ovarian response to gonadotrophin stimulation. This increased sensitivity to follicle-stimulating hormone may be especially useful in poor responders. The potential future applications for aromatase inhibitors in infertility management are also discussed.

Aromatase inhibition for ovarian stimulation: future avenues for infertility management

Ovarian stimulation is applied during infertility management either alone or in conjunction with intrauterine insemination and assisted reproductive technologies. At the present time, the two main medications used for ovarian stimulation include an oral antiestrogen, clomiphene citrate, and injectable gonadotropins. In spite of the high ovulation rate with the use of clomiphene citrate, the pregnancy rate is much lower. In clomiphene citrate failures, gonadotropin injections have generally been used as the next treatment option. Treatment with gonadotropins is difficult to control and characteristically associated with increased risk of severe ovarian hyperstimulation syndrome and high multiple pregnancies. Therefore, an effective oral treatment that could be used without risk of hyperstimulation and with minimal monitoring is the preferred therapy. We hypothesize that aromatase inhibitors can be administered early in the follicular phase to induce ovulation by releasing the hypothalamus or pituitary from estrogen negative feedback. Based on this hypothesis, we have reported the success of aromatase inhibitors in induction and augmentation of ovulation in addition to improving ovarian response to gonadotropin stimulation. Moreover, there are other potential applications for aromatase inhibitors in infertility management, including improving implantation in assisted reproduction and in-vitro maturation.

Chronology of hemodynamic changes in asymptomatic in vitro fertilization patients and relationship with ovarian steroids and cytokines

OBJECTIVE

To characterize the chronology of hemodynamic changes in in vitro fertilization (IVF) cycles and its relationship with circulating ovarian steroids, cytokines, and their mediator nitric oxide.

DESIGN

Prospective, cross-sectional study.

SETTING

University teaching hospital.

PATIENT(S)

Eighty-eight IVF patients.

INTERVENTION(S)

Ovarian stimulation with FSH under pituitary suppression.

MAIN OUTCOME MEASURE(S)

Circulating levels of estradiol, progesterone, nitrite/nitrate, interleukin-6, vascular endothelial growth factor, tumor necrosis factor alpha, aldosterone, norepinephrine, as well as measurements of plasma renin activity and mean arterial pressure.

RESULT(S)

The maximal stimulation of the renin-aldosterone and sympathetic nervous systems was seen 7 days after hCG administration, although values still remained elevated over normal control values on day of hCG + 11. Mean arterial pressure in IVF patients remained significantly reduced throughout the luteal phase. Changes in the stimulation of the renin-aldosterone system correlated temporally with progesterone but not estradiol levels. No significant changes were observed in circulating concentrations of cytokines investigated or nitric oxide.

CONCLUSION(S)

The circulatory changes and the homeostatic activation of the renin-aldosterone system and sympathetic nervous system that consistently develop in patients undergoing controlled ovarian hyperstimulation for IVF is a feature associated with the luteinization process. These hemodynamic changes occur in the absence of variations in the circulating levels of cytokines potentially involved in ovarian hyperstimulation syndrome.

Effect of angiotensin-converting enzyme inhibitor on renal function in ovarian hyperstimulation syndrome in the rabbit

OBJECTIVE

To investigate renal function and whether captopril prevents alterations in the handling of sodium and water in the ovarian hyperstimulation syndrome (OHSS) in the rabbit.

DESIGN

Experimental study

SETTING

Physiology laboratory.

ANIMAL(S)

Six female New Zealand white rabbits were used as controls, and 13 were hyperstimulated with gonadotropins.

INTERVENTION(S)

Saline or captopril.

MAIN OUTCOME MEASURE(S)

Renal excretory and hemodynamic variables.

RESULT(S)

The 3% extracellular volume expansion in OHSS animals induced a significant elevation in mean arterial pressure by 27%, although increments in natriuresis and diuresis were similar to those observed in controls. The OHSS group had impaired pressure-natriuresis sensitivity compared with controls (0.36 +/- 0.07 microEq/min/g of Na excreted per mm Hg vs. 1.74 +/- 0.45 microEq/min/g of Na excreted per mm Hg; P<.05. Captopril significantly reduced mean arterial pressure (P<.05) and shifted the pressure-natriuresis response to the left by 0.85 +/- 0.17 microEq/min/g of Na excreted per mm Hg (P<.05).

CONCLUSION(S)

In OHSS in the rabbit model, pressure-natriuresis sensitivity is impaired. Angiotensin II may play a significant role in this phenomenon, since angiotensin-converting enzyme inhibition normalized the pressure-natriuresis relationship.

Endocrinological and ultrasonographic variations after immature oocyte retrieval in a natural cycle

BACKGROUND

In-vitro oocyte maturation is an appealing alternative in reproductive medicine but the results obtained are still poor. The aim of our prospective and observational investigation was to study the hormonal modifications that immature follicular aspiration might induce in a natural cycle as well as the implications that these alterations may have in the endometrium.

METHODS

Eleven patients (13 cycles) were included in our in-vitro oocyte maturation programme. Ovaries were scanned with transvaginal probes every day and follicular aspiration was performed when a follicle of 9 mm was visualized. Blood was also drawn for hormonal analysis. Endometrial thickness was recorded every day after oocyte retrieval. Two endometrial biopsies were taken on days 6 and 8 after oocyte retrieval.

RESULTS

We observed a significant drop in serum oestradiol concentrations after immature oocyte retrieval previous to follicle dominance. Immediately after, rises in both FSH and LH were detected. Also, a new dominant follicle started to grow 3-4 days later. Steroid hormones secreted by this newly recruited follicle were significantly lower than in controls, inducing inadequate endometrial thickness.

CONCLUSIONS

These studies show that exogenous hormonal administration might be necessary to achieve a correct endometrial growth when in-vitro oocyte maturation is employed in IVF.

An uncommon etiology of isolated pleural effusion. The ovarian hyperstimulation syndrome

We report three cases of pleural effusion in the context of ovarian stimulation for in vitro fertilization. The ovarian hyperstimulation syndrome usually causes pleural effusion and ascites. When the latter is lacking, an isolated pleural effusion in a pregnant patient can be mistaken for pulmonary embolism. Early recognition of the condition should allow for an appropriate diagnostic and therapeutic management. Except for some rare but life-threatening complications, such as major hypovolemia or respiratory distress syndrome, the spontaneous outcome is usually favorable. The pathogenesis of this condition may involve an increase of capillary permeability due to the release of vasoactive mediators.

Occupational asthma caused by pyrazolone derivative used in silver halide photographic paper

Occupational asthma has been documented in workers exposed to a wide variety of chemical compounds. Reactive dyes have been described as causing occupational asthma in textile industry workers. We report a case of occupational asthma resulting from exposure to pyrazolone dye used in silver halide photographic paper. There is a need for both further surveys of workers exposed to other reactive dyes and careful preventive measures in the handling of such compounds.

Coexistent hemoconcentration and hypoosmolality during superovulation and in severe ovarian hyperstimulation syndrome: a volume homeostasis paradox

OBJECTIVE

To investigate the concomitant time courses of the changes in osmolality and calculated blood volume during the genesis of ovarian hyperstimulation syndrome (OHSS).

DESIGN

Prospective longitudinal study.

SETTING

IVF-ET program in a university-based assisted reproductive technology center.

PATIENT(S)

Thirty women undergoing superovulation for IVF-ET.

INTERVENTION(S)

Blood and urine samples were obtained on seven occasions from the start of FSH stimulation until a pregnancy test. Five women with severe OHSS had daily blood and urine tests during hospitalization.

MAIN OUTCOME MEASURE(S)

Changes in serum and urine osmolality, serum electrolytes, albumin, hemoglobin, and hematocrit.

RESULT(S)

Blood volume in women with OHSS decreased significantly by 20% from days hCG +2 to +4, followed by a sustained increase of 30% above baseline from days hCG +8 to +12. There was no statistically significant change in blood volume in women without OHSS. There was a sharp decrease in serum osmolality in women without OHSS between days 0 and hCG +2, which recovered toward baseline from day 4 after hCG. In women with OHSS, there was an unexpected increase in osmolality of 6 mOsm/kg between days hCG -2 and 0, followed by a decrease of 8 mOsm/kg by day hCG +2; this was sustained until day hCG +12. Patients with OHSS demonstrated a concentration and dilution of their urine during the acute and recovery phases of the syndrome, respectively, despite persistence of the hypoosmolar state.

CONCLUSION(S)

Decreased osmolality in severe OHSS is maintained despite significant decreases and increases in blood volume, suggestive of fundamental alterations in osmoregulation.

Thromboembolic complications associated with reproductive endocrinologic procedures

Thromboembolism as a complication of hormonal ovarian stimulation in the context of artificial reproductive techniques is rare and seems to occur when OHS is present. Although accompanied by high serum estrogen concentrations, hCG seems to play a central role in the development of OHS, which has been observed in women with 17,18-desmolase deficiency who have low estrogen levels after induction of ovulation with hGC. Although there is some evidence that hormonal ovarian stimulation with HMG, leading to elevated estrogen levels, and ovulation induction with hCG in preparation for in vitro fertilization are associated with a state of hypercoagulability, the exact role of estrogens, hCG and the physicochemical changes (fluid shift into third spaces) involved in OHS remain to be elucidated.

Minimal stimulation IVF using clomiphene citrate and oral contraceptive pill pretreatment for LH suppression

OBJECTIVE

To determine if oral contraceptive pill (OC) pre-treatment prior to minimal stimulation IVF using clomiphene citrate (CC) would make the procedure easier to perform by preventing the LH surge and result in pregnancy rates (PRs) comparable to stimulated IVF.

DESIGN

Prospective cohort study.

SETTING

Private tertiary infertility center.

PATIENT(S)

Thirty-two women with tubal or pelvic adhesive disease as the cause of their infertility, ovulatory cycles, under the age of 40, and no male factor.

INTERVENTION(S)

Two-month ovarian-hypothalamic-pituitary axis suppression with OC followed by CC 100 mg on day 3 of the cycle for 8 days, hCG administration midcycle, follicle aspiration, IVF, and embryo transfer.

MAIN OUTCOME MEASURE(S)

Oocytes retrieved, serum LH and estradiol levels, maturity of oocytes, fertilization rates, embryo number and quality, and PRs.

RESULT(S)

Thirty-six patients completed 71 stimulation cycles and 64 follicle aspirations. No LH surges occurred with a mean mature oocytes retrieved of 3.2, 90% fertilization rate, and mean 2.5 embryos transferred. Twenty-one of the 64 cycles resulted in a clinical pregnancy (32.8% PR per retrieval) with 2 other biochemical pregnancies and 3 twin gestations. This was not significantly different from the matched cohort stimulated IVF.

CONCLUSION(S)

Minimal stimulation IVF is a simple, low-cost, and low-risk alternative to stimulated IVF with comparable PRs.

Ovarian hyperstimulation syndrome and benign intracranial hypertension in pregnancy after in-vitro fertilization and embryo transfer: case report

Ovarian hyperstimulation syndrome (OHSS) is a dangerous and sometimes life-threatening complication of ovulation induction with exogenous gonadotrophins. While many complications of severe OHSS are recognized we have only identified one review detailing neurological problems. This report concerns a 32-year-old patient with bilateral tubal blockage who achieved her first pregnancy following in-vitro fertilization (IVF) and embryo transfer. Shortly after embryo transfer she developed clinical signs of moderate OHSS with symptoms which were later diagnosed as benign intracranial hypertension (BIH). The BIH was treated effectively using repeated lumbar puncture and diuretics. Spontaneous labour and delivery occurred at 40 weeks' gestation. There was no neurological sequel and no recurrence of the BIH 2 years after the pregnancy. The possible link between OHSS and BIH is discussed as well as the risks of further pregnancy.

Immature oocyte retrieval with in-vitro oocyte maturation

Early studies of in-vitro fertilization used immature oocytes. The process evolved to retrieving metaphase II oocytes, and was eventually successful. At present, aggressive ovulation induction protocols are the mainstay of assisted reproductive technology programs, but not without increased cost, multiple gestations, morbidity, potential future risks and isolated mortalities. The ability to retrieve each month's cohort of immature oocytes transvaginally opened the door to search for a new option for infertile couples requiring assisted reproductive technology. Immature oocyte retrieval combined with in-vitro oocyte maturation eliminates the stimulation, costs and time that were required to monitor oocytes, along with the short- and long-term complications. The essential components are optimal maturation media and a synchronized endometrium in which the embryos transferred from a truncated follicular phase can implant. The process has been successful in several centers with an acceptable success rate when used in conjunction with a host uterus. Future research with maturation, culture, and endometrial synchronization may allow immature oocyte retrieval with in-vitro oocyte maturation to replace in-vitro fertilization in its present form.

Obstetric outcome of in vitro fertilized pregnancies complicated by severe ovarian hyperstimulation syndrome: a multicenter study

OBJECTIVE

To assess the outcome of pregnancies conceived with the use of IVF that are complicated by severe ovarian hyperstimulation syndrome (OHSS).

DESIGN

A retrospective nationwide multicenter study.

SETTING

Sixteen of 19 tertiary care medical centers in Israel.

PATIENT(S)

All patients undergoing IVF who were hospitalized for severe OHSS between January 1987 and December 1996.

MAIN OUTCOME MEASURE(S)

Pregnancy rate (PR) and rates of multiple gestation, miscarriage, ectopic pregnancy, obstetric complications, and intervention.

RESULT(S)

A total of 163 patients who had severe OHSS after IVF treatment were identified, of whom 142 (87.1%) had undergone ET. The clinical PR was 73.2%; 42.3% were singletons, 33.6% were twins, 17.3% were triplets, and 6.7% were quadruplets. The miscarriage rate was 29.8%, whereas the incidence of ectopic pregnancy was 1.9%. Forty-four percent of all births were premature, and 62.1% of all newborns had low birth weight. The most common antenatal complications were pregnancy-induced hypertension (13.2%), gestational diabetes (5.9%), and placental abruption (4.4%). The rate of cesarean section was 44.1%.

CONCLUSION(S)

Among patients who have severe OHSS after IVF treatment, the pregnancy rate and the rates of multiple gestation, miscarriage, prematurity, low birth weight, pregnancy-induced hypertension, gestational diabetes, and placental abruption are significantly higher than those reported previously for pregnancies conceived with the use of assisted reproductive techniques.

Subpopulations of human granulosa-luteal cells obtained during early timed and during normally timed follicular aspiration in in-vitro fertilization-embryo transfer cycles

OBJECTIVE

To find the differences between human granulosa-luteal cells obtained during early timed follicular aspiration to prevent severe ovarian hyperstimulation syndrome (OHSS) and during normally timed follicular aspiration.

DESIGN

Retrospective analysis of clinical laboratory data.

SETTING

In vitro fertilization unit, University Department of Obstetrics and Gynecology, Ljubljana, Slovenia.

PATIENT(S)

Twenty women undergoing IVF-ET at high risk for OHSS.

INTERVENTION(S)

Cells were obtained from the follicles of women who were stimulated with hMG and hCG during an early timed follicular aspiration of one ovary, 10-12 hours after hCG, and during a normally timed follicular aspiration of the contralateral ovary, 32-36 hours after hCG administration.

MAIN OUTCOME MEASURE(S)

Subpopulations of granulosa-luteal cells were observed by computerized image analysis in which hCG was localized using immunoperoxidase staining.

RESULT(S)

Early timed follicular aspirates contained no oocytes and only a scant number of granulosa cells. Granulosa-luteal cells were smaller than those from normally timed follicular aspirates. We identified three subpopulations in early timed follicular aspirates: nonluteinized, small luteinized, and medium luteinized cells. In normally timed follicular aspirates, four subpopulations were identified, including large luteinized cells. The normally timed follicular aspirates contained more hCG-stained cells. Three staining types of hCG localization were found: on the surface membrane, on the surface membrane and within the cytoplasm, and only within the cytoplasm of cells from normally timed follicular aspirates. Early timed follicular aspirates contained only cells with membrane hCG localization.

CONCLUSION(S)

We found differences in morphometric characteristics and hCG localization between human granulosa-luteal cells obtained during early timed follicular aspiration to prevent severe OHSS and during normally timed follicular aspiration.

The ovarian renin-angiotensin system in reproductive physiology

The identification of the presence of prorenin, renin, angiotensinogen, angiotensin-converting enzyme, angiotensin II (Ang II), and Ang II receptors in the ovary suggests that there is a functional ovarian renin-angiotensin system (RAS). It could play a significant role in such areas of ovarian physiology as follicular development, steroidogenesis, oocyte maturation, ovulation, and follicle atresia. Expression of the ovarian RAS is regulated by gonadotropins. Ang II, a bioactive octapeptide of RAS, has important effects as a paracrine/autocrine regulator at different stages of the reproductive cycle. Ang II modulates ovarian steroidogenesis and formation of the corpus luteum and also stimulates oocyte maturation and ovulation via Ang II receptors on granulosa cells. In addition, increasing evidence demonstrates that Ang II is a major factor in regulating the function of atretic follicles. In any physiologic system, aberrations result in the development of pathologic states. Disturbances in the ovarian RAS can be the cause or the result of such reproductive disorders as polycystic ovary syndrome, ovarian hyperstimulation syndrome, ovarian tumors, and ectopic pregnancy. Data support the concept of an active and regulated RAS in ovarian follicles. Species differences observed in the expression of ovarian RAS suggest varying functional roles among species with respect to ovarian physiology.