Pathophysiology, treatment and prevention of ovarian hyperstimulation syndrome

Beyond the Umbrella: A Systematic Review of the Interventions for the Prevention of and Reduction in the Incidence and Severity of Ovarian Hyperstimulation Syndrome in Patients Who Undergo In Vitro Fertilization Treatments

Ovarian hyperstimulation syndrome (OHSS) is the main severe complication of ovarian stimulation for in vitro fertilization (IVF) cycles. The aim of the current study was to identify the interventions for the prevention of and reduction in the incidence and severity of OHSS in patients who undergo IVF not included in systematic reviews with meta-analyses of randomized controlled trials (RCTs) and assess and grade their efficacy and evidence base. The best available evidence for each specific intervention was identified, analyzed in terms of safety/efficacy ratio and risk of bias, and graded using the Oxford Centre for Evidence-Based Medicine (CEBM) hierarchy of evidence. A total of 15 interventions to prevent OHSS were included in the final analysis. In the IVF population not at a high risk for OHSS, follitropin delta for ovarian stimulation may reduce the incidence of early OHSS and/or preventive interventions for early OHSS. In high-risk patients, inositol pretreatment, ovulation triggering with low doses of urinary hCG, and the luteal phase administration of a GnRH antagonist may reduce OHSS risk. In conclusion, even if not supported by systematic reviews with homogeneity of the RCTs, several treatments/strategies to reduce the incidence and severity of OHSS have been shown to be promising.

The ovarian hyperstimulation that truly matters: Admissions, severity and prevention strategies

INTRODUCTION

Ovarian hyperstimulation syndrome (OHSS) is a common but serious complication of in vitro fertilisation. Despite available strategies to reduce OHSS incidence, a small proportion of patients will develop the clinically significant disease with substantial morbidity. Efforts toward better understanding and the prevention of severe disease are required to improve patient outcomes.

AIMS

The aims are to: (1) formulate clinically relevant OHSS classification for inpatient settings and data collection/reporting; (2) estimate OHSS prevalence requiring hospital admission in Victoria; and (3) determine the extent of OHSS preventability with clinical strategies.

MATERIALS AND METHODS

This retrospective cohort study included all OHSS admissions in a tertiary referral centre, January 2016-December 2021, which included approximately 40% of all cases of hospitalisation for OHSS in the State of Victoria. Patient characteristics, treatment regimes, fertility treatment outcomes, timing classification, and clinical markers of disease severity were studied. Patients were classified as having mild, moderate, or severe OHSS with a novel inpatient classification system.

RESULTS

Of 199 OHSS cases presenting to the tertiary institution, 107 were classified as moderate/severe, with no significant difference between age, body mass index, length of stimulation and follicle number between mild/moderate and severe groups. There were more cases of early hyperstimulation (137) compared to late (62) presentation, of which 53% were severe. The average length of stay overall was 3.1 days, and 5.2 days for severe presentations. In 15% of severe cases, an agonist trigger was used.

CONCLUSIONS

The overall prevalence of OHSS requiring hospital admission appears to be low (approximately 0.6% of all stimulated cycles). Established risk factors may not accurately predict clinically relevant OHSS risk. Further monitoring, clinician and patient education are required to minimise the risk of significant OHSS that results in hospital admissions.

Interventions to prevent or reduce the incidence and severity of ovarian hyperstimulation syndrome: a systematic umbrella review of the best clinical evidence

Ovarian hyperstimulation syndrome (OHSS) is a potentially life-threating iatrogenic complication of the early luteal phase and/or early pregnancy after in vitro fertilization (IVF) treatment. The aim of the current study was to identify the most effective methods for preventing of and reducing the incidence and severity of OHSS in IVF patients. A systematic review of systematic reviews of randomized controlled trials (RCTs) with meta-analysis was used to assess each potential intervention (PROSPERO website, CRD 268626) and only studies with the highest quality were included in the qualitative analysis. Primary outcomes included prevention and reduction of OHSS incidence and severity. Secondary outcomes were maternal death, incidence of hospital admission, days of hospitalization, and reproductive outcomes, such as incidence of live-births, clinical pregnancies, pregnancy rate, ongoing pregnancy, miscarriages, and oocytes retrieved. A total of specific interventions related to OHSS were analyzed in 28 systematic reviews of RCTs with meta-analyses. The quality assessment of the included studies was high, moderate, and low for 23, 2, and 3 studies, respectively. The certainty of evidence (CoE) for interventions was reported for 37 specific situations/populations and resulted high, moderate, and low-to-very low for one, 5, and 26 cases, respectively, while it was not reported in 5 cases. Considering the effective interventions without deleterious reproductive effects, GnRH-ant co-treatment (36 RCTs; OR 0.61, 95% C 0.51 to 0.72, n = 7,944; I² = 31%) and GnRH agonist triggering (8 RCTs; OR 0.15, 95% CI 0.05 to 0.47, n = 989; I² = 42%) emerged as the most effective interventions for preventing OHSS with a moderate CoE, even though elective embryo cryopreservation exhibited a low CoE. Furthermore, the use of mild ovarian stimulation (9 RCTs; RR 0.26, CI 0.14 to 0.49, n = 1,925; I² = 0%), and dopaminergic agonists (10 RCTs; OR 0.32, 95% CI 0.23 to 0.44, n = 1,202; I² = 13%) coadministration proved effective and safe with a moderate CoE. In conclusion, the current study demonstrates that only a few interventions currently can be considered effective to reduce the incidence of OHSS and its severity with high/moderate CoE despite the numerous published studies on the topic. Further well-designed RCTs are needed, particularly for GnRH-a down-regulated IVF cycles.

Severe Ovarian Hyperstimulation Syndrome in the Setting of In Vitro Fertilization Treatment

Ovarian hyperstimulation syndrome (OHSS) is one of the complications of pharmacological ovarian stimulation used in fertility treatments. This syndrome is characterized by increased vascular permeability secondary to stimulation, resulting in a fluid shift from the intravascular space to the third-space compartments. Patients developing OHSS can experience severe complications, including ascites, pleural effusions, and shock. Here, we present a case of OHSS in the setting of recent transvaginal oocyte retrieval, leading to severe ascites, pleural effusion, and hypotension requiring urgent intervention.

Intrafollicular fluid metabolic abnormalities in relation to ovarian hyperstimulation syndrome: Follicular fluid metabolomics via gas chromatography-mass spectrometry

INTRODUCTION

Ovarian hyperstimulation syndrome (OHSS) is the most serious iatrogenic complication of ovulation stimulation during assisted reproductive technology. The main objective of this study was to investigate intrafollicular fluid metabolic change profiles of OHSS in non-ovarian etiologic infertility women (CON) and polycystic ovarian syndrome patients (PCOS).

METHODS

87 infertile women were divided into four subgroups: CON-Norm (CON with normal ovarian response), CON-OHSS (CON with OHSS), PCOS-Norm (PCOS with normal ovarian response), and PCOS-OHSS (PCOS with OHSS). The intrafollicular fluid metabolic profiles were analyzed with gas chromatography-mass spectrometry. The multivariable-adjusted conditional logistic regression was applied to assess the association of metabolites with OHSS risk.

RESULTS

We identified 17 and 3 metabolites that related to OHSS risk in CON and PCOS, respectively. 13 OHSS risk-related metabolites in CON were unsaturated fatty acids, 8 of which were also the significantly altered metabolites between all PCOS and CON-Norm.

CONCLUSION

Our study may shed light on the role of intrafollicular fluid metabolic abnormalities in the pathophysiology of OHSS. The findings suggested that there might be some metabolic heterogeneities underlying the development of OHSS in CON and PCOS women and indicated possible shared etiological factors in the development of PCOS and OHSS.

Frozen embryo transfer in the menstrual cycle after moderate-severe ovarian hyperstimulation syndrome: a retrospective analysis

BACKGROUND

Ovarian hyperstimulation syndrome (OHSS) is a rare but serious complication of controlled ovarian stimulation. Frozen-embryo transfer (ET) is prompted to be performed in the next menstrual cycles after cancellation of fresh-ET after occurrence of OHSS. However, effects of frozen-ET in the second menstrual cycle have never been investigated. Therefore, this study aimed to assess this in the menstrual cycle after OHSS.

METHODS

The OHSS group included 342 women with moderate-severe OHSS who underwent the first frozen-ET in the second menstrual cycle in the First Affiliated Hospital of Anhui Medical University from June 2018 to September 2019. A total of 342 women without OHSS who received frozen-ET in the second menstrual cycle were selected as control group matched by age, body mass index, fertility history, ovulation induction scheme. Uni- and multi-variable conditional logistic regression was used to estimate the association between moderate-severe OHSS and pregnancy outcomes.

RESULTS

There were no significant differences in maternal outcomes (miscarriage, preterm birth and pregnancy complications including gestational diabetes mellitus, pregnancy-induced hypertension, placenta previa, premature rupture of membranes and postpartum hemorrhage) and in neonatal outcome (birth-weight and body length, neonatal congenital diseases and other complications) between the two groups in either uni- or multi-variable models.

CONCLUSIONS

Frozen-ET in the menstrual cycle after OHSS has similar maternal and neonatal outcomes as in women without OHSS. This study indicates that frozen-ET could be performed in the second menstrual cycle in women who recovered from moderate-severe OHSS.

Does the controlled ovarian stimulation increase the weight of women undergoing IVF treatment?

OBJECTIVE

Women undergoing assisted reproductive treatment are usually concerned about the side effects caused by high doses of gonadotropin. A common inquiry of patients is concerning the weight gain as a consequence. The aim of this study was to evaluate if controlled ovarian stimulation increase the weight of women undergoing IVF treatment. Study design This retrospective cohort study included 734 women undergoing IVF treatment between January 2017 and May 2018 and had body weight measured on the day of ovarian stimulation starting (basal-weight) and on the hCG trigger day (hCG-weight). The difference of hCG-weight and basal-weight was calculated and correlated to number of oocytes retrieved and ovarian stimulation protocol. For 358 women, two international validated questionnaires to evaluate the anxiety and binge eating were applied at the end of ovarian stimulation and also associated to the body weight gain.

RESULTS

The basal-weight and hCG-weight were paired compared and demonstrate a statistically significant weight gain from basal to hCG-weight of a mean of 387.7 ± 720.4 g (p < 0.001). The weight gain had a positive correlation with the number of oocytes retrieved (Pearson correlation, r = 0.181; p < 0.001) but no correlation with the ovarian stimulation protocol. Regarding the questionnaires answered by patients, neither anxiety score (Pearson: r = -0,031; p = 0,561) nor binge eating score (Pearson: r = 0,069; p = 0,199) were correlated with weight gain from basal-weight to hCG- weight. However, patients who felt eating more during the treatment had a higher weight gain (p < 0.001) independently of the number of oocytes retrieved.

CONCLUSIONS

The weight gain is possibly a result from edema and is clinically irrelevant despite of the statistical significance and will probably be resolved in some days after oocytes retrieval. A small "weight gain" was observed and associated to the number of oocytes retrieved regardless of protocol and medication used in the ovarian stimulation.

Secretory products of the corpus luteum and preeclampsia

BACKGROUND

Despite significant advances in our understanding of the pathophysiology of preeclampsia (PE), there are still many unknowns and controversies in the field. Women undergoing frozen-thawed embryo transfer (FET) to a hormonally prepared endometrium have been found to have an unexpected increased risk of PE compared to women who receive embryos in a natural FET cycle. The differences in risk have been hypothesized to be related to the absence or presence of a functioning corpus luteum (CL).

OBJECTIVE AND RATIONALE

To evaluate the literature on secretory products of the CL that could be essential for a healthy pregnancy and could reduce the risk of PE in the setting of FET.

SEARCH METHODS

For this review, pertinent studies were searched in PubMed/Medline (updated June 2020) using common keywords applied in the field of assisted reproductive technologies, CL physiology and preeclampsia. We also screened the complete list of references in recent publications in English (both animal and human studies) on the topics investigated. Given the design of this work as a narrative review, no formal criteria for study selection or appraisal were utilized.

OUTCOMES

The CL is a major source of multiple factors regulating reproduction. Progesterone, estradiol, relaxin and vasoactive and angiogenic substances produced by the CL have important roles in regulating its functional lifespan and are also secreted into the circulation to act remotely during early stages of pregnancy. Beyond the known actions of progesterone and estradiol on the uterus in early pregnancy, their metabolites have angiogenic properties that may optimize implantation and placentation. Serum levels of relaxin are almost undetectable in pregnant women without a CL, which precludes some maternal cardiovascular and renal adaptations to early pregnancy. We suggest that an imbalance in steroid hormones and their metabolites and polypeptides influencing early physiologic processes such as decidualization, implantation, angiogenesis and maternal haemodynamics could contribute to the increased PE risk among women undergoing programmed FET cycles.

WIDER IMPLICATIONS

A better understanding of the critical roles of the secretory products of the CL during early pregnancy holds the promise of improving the efficacy and safety of ART based on programmed FET cycles.

Expression of tissue factor and tissue factor pathway inhibitors during ovulation in rats: a relevance to the ovarian hyperstimulation syndrome

BACKGROUND

Blood coagulation has been associated with ovulation and female infertility. In this study, the expression of the tissue factor system was examined during ovulation in immature rats; the correlation between tissue factor and ovarian hyperstimulation syndrome (OHSS) was evaluated both in rats and human follicular fluids.

METHODS

Ovaries were obtained at various times after human chorionic gonadotropin (hCG) injection to investigate the expression of tissue factor system. Expression levels of ovarian tissue factor, tissue factor pathway inhibitor (Tfpi)-1 and Tfpi-2 genes and proteins were determined by real-time quantitative polymerase chain reaction (qPCR), and Western blot and immunofluorescence analyses, respectively. Expression levels of tissue factor system were also investigated in ovaries of OHSS-induced rats and in follicular fluid of infertile women.

RESULTS

The expression of tissue factor in the preovulatory follicles was stimulated by hCG, reaching a maximum at 6 h. Tissue factor was expressed in the oocytes and the preovulatory follicles. Tfpi-2 mRNA levels were mainly increased by hCG in the granulosa cells whereas the mRNA levels of Tfpi-1 were decreased by hCG. Human CG-stimulated tissue factor expression was inhibited by the progesterone receptor antagonist. The increase in Tfpi-2 expression by hCG was decreased by the proliferator-activated receptor γ (PPARγ) antagonist. Decreased expression of the tissue factor was detected in OHSS-induced rats. Interestingly, the tissue factor concentrations in the follicular fluids of women undergoing in vitro fertilization were correlated with pregnancy but not with OHSS.

CONCLUSIONS

Collectively, the results indicate that tissue factor and Tfpi-2 expression is stimulated during the ovulatory process in rats; moreover, a correlation exists between the levels of tissue factor and OHSS in rats but not in humans.

Electroacupuncture Reduces Oocyte Number and Maintains Vascular Barrier Against Ovarian Hyperstimulation Syndrome by Regulating CD200

Ovarian hyperstimulation syndrome (OHSS) is a common complication caused by ovulatory stimulation therapy, which manifests as an increase in ovarian volume, an increase in the number of oocytes retrieved, and increased vascular permeability throughout the body and especially in ovarian tissue. In our previous study, we found that electroacupuncture (EA) could prevent the progression of OHSS, by mainly affecting ovary. However, the specific molecules and the mechanism of this process were still unknown. In order to explore the underlying mechanism, OHSS rat model was established and EA treatment was performed, which was followed by proteomic analysis of ovaries. Results showed a significant increase in the expression level of CD200 in the ovaries of OHSS group treated with EA than those of OHSS group. Clinical data showed that the level of CD200 in follicular fluid was negatively correlated with the number of oocytes retrieved and serum E2 level. Further in vitro experiments showed a concentration-dependent role of human chorionic gonadotropin (hCG) in reducing CD200 and CD200R levels, and increasing inflammatory cytokine levels in cultured KGN cells. In human umbilical vein endothelial cells (HUVECs), the vascular barrier function was improved by CM (cultural medium from KGN cell) which treated with CD200Fc (CD200R agonist). Meanwhile, the results of in vivo experiments indicated that EA reduced the number of ovarian corpora lutea, decreased inflammatory response, and improved the vascular barrier function by increasing the expression of CD200 and CD200R in rat ovaries. These findings suggest that EA treatment may reduce oocyte number and maintain vascular barrier against OHSS through ovarian anti-inflammatory response mediated by CD200. Therefore, this study is the first to identify CD200 as a main of EA in the ovary and elucidate the possible mechanism of EA on preventing and treating OHSS, which provide a scientific basis for CD200 as an effector and indicator in EA treatment.

Effect of GnRH-antagonist, mifepristone and letrozole on preventing ovarian hyperstimulation syndrome in rat model

RESEARCH QUESTION

Can luteolysis-targeted drugs, gonadotrophin-releasing hormone antagonist (GnRH-ant), mifepristone and letrozole, administered separately or in combination, prevent the progression of ovarian hyperstimulation syndrome (OHSS) in a rat model?

DESIGN

Thirty-six female Wistar rats were randomly divided into six groups, including control group (OHSS group, ovarian hyperstimulation-induced OHSS); GnRH-ant group (OHSS with GnRH-ant treatment); mifepristone group (OHSS with mifepristone treatment); letrozole group (OHSS with letrozole treatment); combination group (OHSS with GnRH-ant, mifepristone and letrozole treatment in combination). The main outcomes were the alterations in OHSS-related indices, including ovarian weight, vascular permeability, serum oestradiol and progesterone levels, corpus luteum proportion and diameter, ovarian vascular endothelial growth factor (VEGF), interleukin 6 (IL-6), caspase-3 and cleaved caspase-3 levels.

RESULTS

No significant difference was found in body weight gain among the six groups. Compared with the control group, the OHSS group showed significant increases in all OHSS-related indices. GnRH-ant treatment showed decreases in vascular permeability, serum oestradiol level, corpus luteum diameter, ovarian VEGF /IL-6 mRNA levels, and increases in ovarian caspase-3 and cleaved caspase-3 levels. Mifepristone treatment demonstrated reduction in serum progesterone level and corpus luteum diameter, and elevation in ovarian caspase-3 and cleaved caspase-3 levels. Letrozole treatment displayed a decline in serum oestradiol level and corpus luteum diameter, and up-regulation in ovarian caspase-3 and cleaved caspase-3 levels. The combination treatment by GnRH-ant, mifepristone and letrozole showed enhanced synergistic effect on reducing OHSS-related indices.

CONCLUSIONS

GnRH-ant, mifepristone and letrozole are beneficial in preventing the progression of OHSS through different luteolytic mechanisms. Cocktail style treatment shows enhanced synergistic effect on preventing the progression of OHSS.

Successful reversal of ovarian hyperstimulation syndrome in a mouse model by rapamycin, an mTOR pathway inhibitor

Ovarian hyperstimulation syndrome (OHSS) is a potentially life-threatening, iatrogenic complication of ovarian stimulation in assisted reproduction technology. This complex syndrome is characterised by enlarged ovaries with multiple corpora luteum, elevated sex steroid hormones in serum and increased capillary permeability. Until now, the pathogenesis of OHSS remains obscure, and no absolute strategy can fully prevent OHSS without any side effect on ovulation and clinical pregnancy. Using cultured human or mouse granulosa cells, our study revealed the time-dependent activation of the mTOR signaling pathway after human chorionic gonadotropin (hCG) treatment. The involvement of the mTOR signaling pathway was also observed in the development of OHSS in a mouse model. Selectively inhibiting mTOR signals by only two injections of rapamycin (2 mg/kg body weight), before or just after hCG treatment, significantly reduced vascular leakage and the severity of OHSS symptoms. Although ovarian angiogenesis was significantly inhibited, rapamycin could not decrease the elevated levels of vascular endothelial growth factor, IL-6 and IL-11 in OHSS ovaries. Further study showed the functional roles of the mTOR signaling pathway in the hyperstimulation-induced ovarian extracellular matrix remodeling as the expression of α2M, a broad proteolytic inhibitor in both ovary and serum, was dramatically decreased after rapamycin treatment. Since a single injection of rapamycin during superovulation had no side effects on ovulation and early embryonic development, we propose rapamycin may be a good candidate to lower and prevent the risk of OHSS in the future.

Ovarian hyperstimulation syndrome: a clinical retrospective study on 565 inpatients

The aim of this study was to analyze clinical manifestations of 565 ovarian hyperstimulation syndrome (OHSS) inpatients in the largest Obstetrics and Gynecology hospital in China from year 2010 to 2017, to get more understanding of epidemiologic features of this disease, and to provide some insight on the diagnosis, treatment, and preventions of OHSS. It is a clinical retrospective study. In the 565 cases that developed OHSS over an eight-year period between 2010 and 2017 were reviewed, we assessed patients' general characteristics, clinical manifestations, treatment, prognosis, and the relationship between different indicators and the severity of OHSS. Totally 12 kinds of ovulation induction protocols (Protocol 1: CC; Protocol 2: Gn; Protocol 3: hCG; Protocol 4: GnRh-a; Protocol 5: CC & Gn; Protocol 6: CC & hCG; Protocol 7: Gn & hCG; Protocol 8: GnRh-a & Gn; Protocol 9: CC & Gn & hCG; Protocol 10: GnRh-a & CC & Gn; Protocol 11: Letrozole & Gn & hCG; Protocol 12:GnRh-a & Letrozole & Gn) were analyzed and the Odds Ratio (OR) of each protocol were calculated. Five hundred and sixty-five patients were reviewed in our study. In all these patients, the number of hospitalizations, mean age, primary infertility rate, and pregnancy rate did not differ through the last 8 years. From which we may infer that the incidence rate of OHSS may not change over the last 8 years. Older patients tend to develop into more severe stage easily. The pregnancy rate was much lower in mild stage patients, but no difference was found between patients in moderate, severe and critical stage. Oocytes retrieval is strongly associated with severity. PCOS history, irregular menstrual cycle and infertility type do not seem to affect the severity of OHSS. Twelve kinds of ovulation induction protocols were analyzed, OR of different protocols were calculated, what is noteworthy is that patients who used GnRh easily developed more severe OHSS than the patients who received oocytes retrieval. We suggest that we may choose ovulation induction protocols according to the OR table while treating women with high-risk factors.

Potential influence of the corpus luteum on circulating reproductive and volume regulatory hormones, angiogenic and immunoregulatory factors in pregnant women

Cardiovascular function is impaired and preeclampsia risk elevated in women conceiving by in vitro fertilization (IVF) in the absence of a corpus luteum (CL). Here, we report the serial evaluation of hormones and other circulating factors in women who conceived with (or without) IVF. After a prepregnancy baseline, the study participants (n = 19-24/cohort) were evaluated six times during pregnancy and once postpartum (~1.6 yr). IVF pregnancies were stratified by protocol and CL number, i.e., ovarian stimulation (>1 CL) or hypothalamic-pituitary suppression (0 CL) versus spontaneous conceptions (1 CL). Results include the following: 1) relaxin was undetectable throughout pregnancy (including late gestation) in the 0 CL cohort, but markedly elevated in ~50% of women in the >1 CL cohort; 2) progesterone, plasma renin activity, and aldosterone transiently surged at 5-6 gestational weeks in the >1 CL group; 3) soluble vascular endothelial growth factor-1 (sFLT-1) abruptly increased between 5-6 and 7-9 gestational weeks in all three participant cohorts, producing a marked elevation in sFLT-1/PLGF (placental growth factor) ratio exceeding any other time point during pregnancy; 4) sFLT-1 was higher throughout most of gestation in both IVF cohorts with or without abnormal obstetrical outcomes; 5) during pregnancy, C-reactive protein (CRP) increased in 0 and 1 CL, but not >1 CL cohorts; and 6) plasma protein, but not hemoglobin, was lower in the >1 CL group throughout gestation. The findings highlight that, compared with spontaneously conceived pregnancy, the maternal milieu of IVF pregnancy is not physiologic, and the specific perturbations vary according to IVF protocol and CL status.

MPH, Shigemi D, MPH, Matsui1 MPH H, Fushimi K, Ph.D., Yasunaga H, Ph.D.. Artificial colloids versus human albumin for the treatment of ovarian hyperstimulation syndrome: A retrospective cohort study

BACKGROUND

The optimal colloid solution for the treatment of ovarian hyperstimulation syndrome (OHSS) remains to be established.

OBJECTIVE

We aimed to compare artificial colloids (AC) with human albumin (HA) for the treatment of OHSS.

MATERIALS AND METHODS

In this retrospective cohort study, data for OHSS participants were collected from a national inpatient database in Japan. The participants received intravenous fluid management with AC (n = 156) or HA (n = 127). We compared the two groups in terms of the length of stay, development of post-treatment complications, and termination surgery.

RESULTS

In multivariable linear regression analyses for log-transformed length of stay with reference to the OHSS participants receiving AC, the regression coefficient (95% confidence interval) in participants receiving HA was 0.03 (-0.04-0.09, p = 0.42). Thromboembolism occurred in two participants in the HA group and three participants in the AC group. Two participants in the HA group suffered renal failure during hospitalization. No participants underwent termination surgery in the two groups.

CONCLUSION

The present results showed comparable efficacy between AC and HA for the treatment of OHSS. There were no significant differences in post-treatment complications between the two groups.

Association of IL-17 and IL-23 follicular fluid concentrations and gene expression profile in cumulus cells from infertile women at risk for ovarian hyperstimulation syndrome

This study determined the association between the levels of interleukin (IL)-17 and IL-23 in follicular fluid (FF), as well as their mRNA levels in cumulus cells from infertile women at risk for ovarian hyperstimulation syndrome (OHSS). In this case-controlled study, the control group (n = 40) was infertile women whose partners had male factor infertility, whereas the case group (n = 40) was infertile women at risk of OHSS. IL-17 and IL-23 concentrations in FF were measured using an enzyme-linked immunosorbent assay method, whereas the mRNA expression levels of IL-17 and IL-23 of cumulus cells were determined using RT-PCR. Significantly higher levels of IL-17 were seen in the case group (p = 0.04), whereas there was no significant difference in IL-23 concentrations between the two groups (p = 0.3). The mRNA levels of IL-17 and IL-23 showed no significant differences. In the case group, there was a positive significant correlation between the IL-23 concentration in FF and the oocyte maturation rates (p = 0.01). In the case group, the number of follicles, MII oocytes, immature oocytes, fertilized oocytes and number of embryos were significantly higher than the control group (p < 0.05). Our findings showed that the mRNA expressions of IL-17 and IL-23 were similar in the two groups, and IL-17 was increased in the case group.

Activation of NF-κB signaling pathway during HCG-induced VEGF expression in luteal cells

Vascular endothelial growth factor (VEGF) plays an essential role in luteal angiogenesis, the present study therefore utilized luteal cells cultured in vitro to further investigate the activation and contribution of nuclear factor (NF)-κB to VEGF expression induced by human chorionic gonadotrophin (HCG). The present results showed HCG induced VEGF expression as well as hypoxia-inducible factor (HIF)-1α mRNA and protein expressions, which was blocked by NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC). Further analysis found that these increases of VEGF and HIF-1α mRNA induced by HCG were also blocked by NF-κB siRNA transfection, which was consistent with PDTC treatment. However, HIF-1α siRNA treatment significantly decreased HCG induced-VEGF expression with no effect on NF-κB mRNA expression. Furthermore, combination of HIF-1α siRNA and PDTC treatment did not further decrease VEGF mRNA expression, and the result of chromatin immunoprecipitation indicated NF-κB may regulate HIF-1α transcription through binding with its promoter. Taken together, the present results clearly demonstrated that NF-κB was activated to regulate VEGF expression by increasing HIF-1α transcription in luteal cells treated with HCG. Therefore, the present study provided a new and important mechanism of luteal angiogenesis during the formation of corpus luteum in mammals.

A Case with Severe Endometriosis, Ovarian Hyperstimulation Syndrome, and Isolated Unilateral Pleural Effusion after IVF

We present a very rare case of right-sided isolated pleural effusion in a patient with severe endometriosis who, in relation to in vitro fertilization (IVF), developed ovarian hyperstimulation syndrome (OHSS). Earlier laparotomy showed grade IV endometriosis including endometriotic implants of the diaphragm. The patient had no known risk factors for OHSS and only a moderate number of oocytes aspirated. She received, however, repeated hCG injections for luteal support. The patient did not achieve pregnancy but was hospitalized due to pain in the right side of the chest and dyspnoea. A chest computed tomography (CT) showed a pleural effusion on the right side. Total of 1000 ml of pleural fluid was drained after a single thoracentesis. After three days, the symptoms and fluid production ceased. Ascites is a common finding in OHSS, but pleural effusions are rare. Further, isolated pleural effusions have not previously been described in a patient with endometriosis. We suggest that the repeated hCG injections induced effusions from the endometriotic lesions at the diaphragm and as a consequence this patient developed isolated hydrothorax.

Interventions for the prevention of OHSS in ART cycles: an overview of Cochrane reviews

BACKGROUND

Ovarian hyperstimulation syndrome (OHSS) in assisted reproductive technology (ART) cycles is a treatment-induced disease that has an estimated prevalence of 20% to 33% in its mild form and 3% to 8% in its moderate or severe form. These numbers might even be higher for high-risk women such as those with polycystic ovaries or a high oocyte yield from ovum pickup.

OBJECTIVES

The objective of this overview is to identify and summarise all evidence from Cochrane systematic reviews on interventions for prevention or treatment of moderate, severe and overall OHSS in couples with subfertility who are undergoing ART cycles.

METHODS

Published Cochrane systematic reviews reporting on moderate, severe or overall OHSS as an outcome in ART cycles were eligible for inclusion in this overview. We also identified Cochrane submitted protocols and title registrations for future inclusion in the overview. The evidence is current to 12 December 2016. We identified reviews, protocols and titles by searching the Cochrane Gynaecology and Fertility Group Database of Systematic Reviews and Archie (the Cochrane information management system) in July 2016 on the effectiveness of interventions for outcomes of moderate, severe and overall OHSS. We undertook in duplicate selection of systematic reviews, data extraction and quality assessment. We used the AMSTAR (Assessing the Methodological Quality of Systematic Reviews) tool to assess the quality of included reviews, and we used GRADE methods to assess the quality of the evidence for each outcome. We summarised the characteristics of included reviews in the text and in additional tables.

MAIN RESULTS

We included a total of 27 reviews in this overview. The reviews were generally of high quality according to AMSTAR ratings, and included studies provided evidence that ranged from very low to high in quality. Ten reviews had not been updated in the past three years. Seven reviews described interventions that provided a beneficial effect in reducing OHSS rates, and we categorised one additional review as 'promising'. Of the effective interventions, all except one had no detrimental effect on pregnancy outcomes. Evidence of at least moderate quality indicates that clinicians should consider the following interventions in ART cycles to reduce OHSS rates.• Metformin treatment before and during an ART cycle for women with PCOS (moderate-quality evidence).• Gonadotrophin-releasing hormone (GnRH) antagonist protocol in ART cycles (moderate-quality evidence).• GnRH agonist (GnRHa) trigger in donor oocyte or 'freeze-all' programmes (moderate-quality evidence). Evidence of low or very low quality suggests that clinicians should consider the following interventions in ART cycles to reduce OHSS rates.• Clomiphene citrate for controlled ovarian stimulation in ART cycles (low-quality evidence).• Cabergoline around the time of human chorionic gonadotrophin (hCG) administration or oocyte pickup in ART cycles (low-quality evidence).• Intravenous fluids (plasma expanders) around the time of hCG administration or oocyte pickup in ART cycles (very low-quality evidence).• Progesterone for luteal phase support in ART cycles (low-quality evidence).• Coasting (withholding gonadotrophins) - a promising intervention that needs to be researched further for reduction of OHSS.On the basis of this overview, we must conclude that evidence is currently insufficient to support the widespread practice of embryo cryopreservation.

AUTHORS' CONCLUSIONS

Currently, 27 reviews in the Cochrane Library were conducted to report on or to try to report on OHSS in ART cycles. We identified four review protocols but no new registered titles that can potentially be included in this overview in the future. This overview provides the most up-to-date evidence on prevention of OHSS in ART cycles from all currently published Cochrane reviews on ART. Clinicians can use the evidence summarised in this overview to choose the best treatment regimen for individual patients - a regimen that not only reduces the chance of developing OHSS but does not compromise other outcomes such as pregnancy or live birth rate. Review results, however, are limited by the lack of recent primary studies or updated reviews. Furthermore, this overview can be used by policymakers in developing local and regional protocols or guidelines and can reveal knowledge gaps for future research.