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

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.

Clinical Features of Severe Ovarian Hyperstimulation Syndrome with Hydrothorax

PROBLEM

Does the presence of hydrothorax suggest that severe ovarian hyperstimulation syndrome (OHSS) is associated with more severe conditions and worse pregnancy outcomes?

METHOD OF STUDY

The clinical data for 868 hospital patients with severe OHSS following IVF-ET at Peking University Third Hospital between 1 January 2016 and 21 July 2021 were retrospectively analysed. The patients were divided into two groups, the ascites alone group (n = 417) and the ascites combined with hydrothorax group (n = 451), to investigate the clinical features and pregnancy outcomes of patients with severe ovarian hyperstimulation syndrome (OHSS) combined with hydrothorax plus ascites.

RESULTS

The clinical data for 868 hospital patients with severe OHSS following IVF-ET were included. A total of 51.96% of patients with severe OHSS had hydrothorax plus ascites, mainly bilateral and moderate hydrothorax. Most cases with hydrothorax could be monitored and observed, and only 2.66% of the cases required thoracentesis and pleural drainage. Clinically, the time to visit due to worsening symptoms was longer; the hospital stay was shorter; and the OHSS-related laboratory tests, such as white blood cells (WBC), haematocrit (HCT), and ovarian diameter, were less severe in the ascites combined with hydrothorax group than in the ascites alone group. For live-birth outcomes of IVF-ET, the presence and the volume of hydrothorax were not independent risk factors, while the late onset of OHSS (odds ratio [OR]: 0.857 95% confidence interval [CI]: 0.795, 0.925) and a history of foetal reduction (OR: 13.796 95% CI: 1.808, 105.288) were independent protective factors for live birth.

CONCLUSIONS

Patients with severe OHSS combined with hydrothorax plus ascites have less severe clinical manifestations and laboratory tests than those with ascites alone. The presence and the volume of hydrothorax are unrelated to live-birth outcomes following in vitro fertilization and embryo transfer (IVF-ET).

Global Transcriptional Profiling of Granulosa Cells from Polycystic Ovary Syndrome Patients: Comparative Analyses of Patients with or without History of Ovarian Hyperstimulation Syndrome Reveals Distinct Biomarkers and Pathways

Ovarian hyperstimulation syndrome (OHSS) is often a complication of polycystic ovarian syndrome (PCOS), the most frequent disorder of the endocrine system, which affects women in their reproductive years. The etiology of OHSS is multifactorial, though the factors involved are not apparent. In an attempt to unveil the molecular basis of OHSS, we conducted transcriptome analysis of total RNA extracted from granulosa cells from PCOS patients with a history of OHSS (n = 6) and compared them to those with no history of OHSS (n = 18). We identified 59 significantly dysregulated genes (48 down-regulated, 11 up-regulated) in the PCOS with OHSS group compared to the PCOS without OHSS group (p-value < 0.01, fold change >1.5). Functional, pathway and network analyses revealed genes involved in cellular development, inflammatory and immune response, cellular growth and proliferation (including DCN, VIM, LIFR, GRN, IL33, INSR, KLF2, FOXO1, VEGF, RDX, PLCL1, PAPPA, and ZFP36), and significant alterations in the PPAR, IL6, IL10, JAK/STAT and NF-κB signaling pathways. Array findings were validated using quantitative RT-PCR. To the best of our knowledge, this is the largest cohort of Saudi PCOS cases (with or without OHSS) to date that was analyzed using a transcriptomic approach. Our data demonstrate alterations in various gene networks and pathways that may be involved in the pathophysiology of OHSS. Further studies are warranted to confirm the findings.

Association between hospital treatment volume and major complications in ovarian hyperstimulation syndrome

OBJECTIVE

An inverse relationship between hospital volume and adverse patient outcomes has been established for many conditions, but has not yet been examined in ovarian hyperstimulation syndrome (OHSS). Given the rarity of severe OHSS, but potential for high morbidity, this study aimed to elucidate the effect of hospital volume on inpatient OHSS-related complications.

METHODS

This is a retrospective observational study querying the National Inpatient Sample, 1/2001-12/2011. Study population was 11,878 patients with OHSS treated at 735 hospitals. Annualized hospital OHSS treatment volume was grouped as: low-volume (1 case/year), mid-volume (>1 but < 3.5 cases/year), and high-volume (≥3.5 cases/year). Main outcome measure was major complication rates stratified by hospital treatment volume, assessed by multinomial regression and binary logistic regression models.

RESULTS

A total of 2,415 (20.3%) patients were treated at low-volume centers, 5,023 (42.3%) at mid-volume centers, and 4,440 (37.4%) at high-volume centers. Patients treated at high-volume centers were more likely to be older and less comorbid with higher incomes and lower body mass index (P < 0.05). High-volume hospitals were more likely to be urban-teaching centers with large bed capacity (P < 0.001). Overall, 1,624 (13.7%) patients experienced a major complication during hospitalization. Patients treated at high-volume hospitals had lower rates of major complications (high: 11.0%, mid: 15.2%, low: 15.6%, P < 0.001). On multivariable analysis, treatment at high-volume hospitals was independently associated with a nearly 20% lower rate of major complications (odds ratio 0.82, 95% confidence interval 0.70-0.97, P = 0.021).

CONCLUSION

Our study suggests that higher hospital treatment volume for OHSS may be associated with improved outcomes.

A Histopathological Evaluation of Ovarian Hyperstimulation Syndrome on Reproductive and Vital Organs and the Role of the VEGF-PKA Pathway in a Mouse Model

Ovarian hyperstimulation syndrome (OHSS) is one of the most common and iatrogenic complications of in vitro fertilization therapy, which is an exaggerated response to excess hormones resulting in the development of a large number of maturing follicles. Although the complications of and reasons for the condition are well known, the overall histopathological effects on systemic organs and the extent of the damage have not been fully elucidated. Besides, the mechanism that underlies the situation is not very well known. The aim of the present work was to analyse the histopathological effects of OHSS on reproductive (uterus and ovary) and vital organs (liver and kidney) and the possible role of the VEGF-PKA pathway in triggering the condition. Balb/c mice were used to establish an OHSS model. The OHSS group were injected with overdose PMSG while the normal responder group were injected with an optimal dose. Histopathological evaluation was utilised in the liver, kidney, ovary, and uterus stained with hematoxylin and eosin, Masson's trichrome, and periodic acid-Schiff stain. The expression profiles of VEGF (vascular endothelial growth factor), PKA (protein kinase A), and p-PKA (an activated form of PKA) were detected with immunohistochemistry and Western blotting. OHSS was demonstrated to have a negative histopathological effect on all of the organs analysed. These effects were associated with an overall increase in the expression levels of VEGF, PKA, and p-PKA. OHSS has a serious histopathological negative effect on the systemic and reproductive organs and is proven to affect overall health, and thus should be considered a dangerous complication during ART techniques. The activation of the VEGF-PKA pathway, which is indicated by the expression levels of VEGF, PKA, and p-PKA, is demonstrated to accompany this complication, which should be further elucidated to understand the mechanisms underlying the condition.

The influence of obesity on incidence of complications in patients hospitalized with ovarian hyperstimulation syndrome

OBJECTIVE

To study the impact of body habitus on risk of complications resulting from ovarian hyperstimulation syndrome (OHSS) in hospitalized patients.

METHODS

This is a retrospective observational study examining the National Inpatient Sample between January 2012 and September 2015. Patients were women < 50 years of age diagnosed with OHSS, classified as non-obese, class I-II obesity, or class III obesity. Intervention included multinomial logistic regression to identify factors associated with obesity and binary logistic regression for independent risk factors for complications. Main outcome measures were incidence of (i) any or (ii) multiple complication(s).

RESULTS

Of 2745 women hospitalized with OHSS, 2440 (88.9%) were non-obese, 155 (5.6%) had class I-II obesity, and 150 (5.5%) had class III obesity. Obese women (either class I-II or III) had a higher degree of comorbidity, had lower incomes, and were less likely to have private insurance than non-obese women (all P < 0.001). Obese women had lower rates of OHSS-related complications than non-obese women (any complication: non-obese 65.2%, class I-II 54.8%, and class III 46.7%, P < 0.001; and multiple complications: non-obese 38.5%, class I-II 32.3%, and class III 20.0%, P < 0.001). In the multivariable model, obesity remained independently associated with a decreased risk of complications (class I-II odds ratio 0.57, 95% confidence interval 0.39-0.83, P = 0.003; class III odds ratio 0.30, 95% confidence interval 0.20-0.44, P < 0.001). Obese women were also less likely to require paracentesis (non-obese 32.8%, class I-II 9.7%, and class III 13.3%, P < 0.001).

CONCLUSION

Our study suggests that obesity is associated with decreased OHSS-related complication rates in hospitalized patients.

Anti-Müllerian Hormone Predictive Levels to Determine The Likelihood of Ovarian Hyper-Response in Infertile Women with Polycystic Ovarian Morphology

BACKGROUND

The objective of this study was to investigate serum levels of anti-Müllerian hormone (AMH) in normal-ovulatory infertile women with polycystic ovarian morphology (PCOM) and their association with ovarian hyper-response.

MATERIALS AND METHODS

This prospective cohort study was carried out on 100 infertile women with PCOM who were treated with an antagonist/agonist triggered stimulation protocol at Shahid Akbar-Abadi Hospital IVF Centre, Tehran, Iran. Serum AMH levels were measured before starting the assisted reproductive technology (ART) cycle and the ovarian hyper-response was evaluated by retrieved oocyte numbers, ooestradiol levels on the triggering day, and the incidence of ovarian hyper-stimulation syndrome (OHSS) clinical signs and symptoms. Logistic regression and the area under the curve (AUC) were used to estimate the effects of AMH and the accuracy of the test.

RESULTS

Receiver operating characteristic (ROC) curve analysis showed that AMH could significantly predict ovarian hyper-response in PCOM patients (AUC=0.73). The estimated threshold value was 4.95 ng/ml, with a specificity of 74.58% (95% confidence interval [CI]: 50.85, 93.22) and sensitivity of 73.17% (95% CI: 48.78, 92.68). Logistic regression results showed a significant interaction between AMH and body mass index (BMI, P=0.008), which indicated that BMI had a moderation effect.

CONCLUSION

Individualized stimulation protocols for patients with isolated PCOM and AMH greater than 4.95 ng/ml may significantly reduce the chances of developing OHSS. However, the AMH cut-off values to predict ovarian hyperresponse differ for different BMI categories among PCOM patients; thus, it becomes a more precise predictive marker with increasing BMI.

Gonadotropin levels at the start of ovarian stimulation predict normal fertilization after hCG re-trigger in GnRH antagonist cycles

PURPOSE

To assess the appropriateness of human chorionic gonadotropin (hCG) re-trigger in poor responders to gonadotropin-releasing hormone agonist (GnRHa) trigger in controlled ovarian stimulation (COS) cycles.

METHODS

The 2251 cycles in 2251 patients triggered with GnRHa for oocyte stimulation, with or without requiring hCG re-trigger between 2013 and 2018, were retrospectively analyzed to compare gonadotropin levels at the start of COS and the rate of normal fertilization between the re-trigger and non-re-trigger group. Furthermore, patients in the re-trigger group were stratified by the rate of normal fertilization (good: ≥60% or poor: <60%) to compare patient demographics, hormone profiles, and clinical outcome between the subgroups.

RESULTS

In the re-trigger group, FSH and LH levels at the start of COS were significantly lower in the good fertilization group than in the poor fertilization group (P < .01). Receiver operating characteristic curves identified cutoff values of the FSH and LH levels of 1.30 and 0.35 mIU/mL, respectively, for predicting ≥60% normal fertilization.

CONCLUSION

Gonadotropin levels at the start of COS are predictors of response to GnRHa trigger and hCG re-trigger necessity, and may serve as indicators to help clinicians appropriately choose hCG re-trigger rather than abandoning the cycles or continuing the first oocyte aspiration attempt.

The freeze-all strategy after IVF: which indications?

The freeze-all strategy is gaining popularity worldwide as an alternative to the conventional fresh embryo transfer. It consists of cryopreservation of the entire embryo cohort and the embryo transfer in a subsequent cycle that takes place separately from ovarian stimulation. The freeze-all strategy was initially a 'rescue' strategy for women at high risk of ovarian hyperstimulation syndrome; however, this approach has been extended to other indications as a scheduled strategy to improve implantation rates. This assumes that ovarian stimulation can alter endometrial receptivity in fresh cycles owing to the effect of supraphysiological levels of steroids on endometrial maturation. The procedure, however, has not been associated with increased live birth rates in all infertile couples, and concerns have been raised about the occurrence of several adverse perinatal outcomes. It is, therefore, crucial to identify in which subgroups of patients a freeze-all strategy could be beneficial. The aim of this review is to summarize current scientific research in this field to highlight potential indications for this strategy and to guide clinicians in their daily practice.

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.

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.

Coasting (withholding gonadotrophins) for preventing ovarian hyperstimulation syndrome

BACKGROUND

Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic and potentially life threatening condition resulting from excessive ovarian stimulation. Reported incidence of moderate to severe OHSS ranges from 0.6% to 5% of in vitro fertilization (IVF) cycles. The factors contributing to OHSS have not been completely explained. The release of vasoactive substances secreted by the ovaries under human chorionic gonadotrophin (hCG) stimulation may play a key role in triggering this syndrome. This condition is characterised by a massive shift of fluid from the intravascular compartment to the third space, resulting in profound intravascular depletion and haemoconcentration.

OBJECTIVES

To assess the effect of withholding gonadotrophins (coasting) on the prevention of ovarian hyperstimulation syndrome in assisted reproduction cycles.

SEARCH METHODS

For the update of this review, we searched the Cochrane Gynaecology and Fertility Group Trials Register, CENTRAL, MEDLINE (PubMed), CINHAL, PsycINFO, Embase, Google, and clinicaltrials.gov to 6 July 2016.

SELECTION CRITERIA

We included only randomized controlled trials (RCTs) in which coasting was used to prevent OHSS.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials and extracted data. They resolved disagreements by discussion. They contacted study authors to request additional information or missing data. The intervention comparisons were coasting versus no coasting, coasting versus early unilateral follicular aspiration (EUFA), coasting versus gonadotrophin releasing hormone antagonist (antagonist), coasting versus follicle stimulating hormone administration at the time of hCG trigger (FSH co-trigger), and coasting versus cabergoline. We performed statistical analysis in accordance with Cochrane guidelines. Our primary outcomes were moderate or severe OHSS and live birth.

MAIN RESULTS

We included eight RCTs (702 women at high risk of developing OHSS). The quality of evidence was low or very low. The main limitations were failure to report live birth, risk of bias due to lack of information about study methods, and imprecision due to low event rates and lack of data. Four of the studies were published only as abstracts, and provided limited data. Coasting versus no coastingRates of OHSS were lower in the coasting group (OR 0.11, 95% CI 0.05 to 0.24; I² = 0%, two RCTs; 207 women; low-quality evidence), suggesting that if 45% of women developed moderate or severe OHSS without coasting, between 4% and 17% of women would develop it with coasting. There were too few data to determine whether there was a difference between the groups in rates of live birth (OR 0.48, 95% CI 0.14 to 1.62; one RCT; 68 women; very low-quality evidence), clinical pregnancy (OR 0.82, 95% CI 0.46 to 1.44; I² = 0%; two RCTs; 207 women; low-quality evidence), multiple pregnancy (OR 0.31, 95% CI 0.12 to 0.81; one RCT; 139 women; low-quality evidence), or miscarriage (OR 0.85, 95% CI 0.25 to 2.86; I² = 0%; two RCTs; 207 women; very low-quality evidence). Coasting versus EUFAThere were too few data to determine whether there was a difference between the groups in rates of OHSS (OR 0.98, 95% CI 0.34 to 2.85; I² = 0%; 2 RCTs; 83 women; very low-quality evidence), or clinical pregnancy (OR 0.67, 95% CI 0.25 to 1.79; I² = 0%; 2 RCTs; 83 women; very low-quality evidence); no studies reported live birth, multiple pregnancy, or miscarriage. Coasting versus antagonistOne RCT (190 women) reported this comparison, and no events of OHSS occurred in either arm. There were too few data to determine whether there was a difference between the groups in clinical pregnancy rates (OR 0.74, 95% CI 0.42 to 1.31; one RCT; 190 women; low-quality evidence), or multiple pregnancy rates (OR 1.00, 95% CI 0.43 to 2.32; one RCT; 98 women; very low-quality evidence); the study did not report live birth or miscarriage. Coasting versus FSH co-triggerRates of OHSS were higher in the coasting group (OR 43.74, 95% CI 2.54 to 754.58; one RCT; 102 women; very low-quality evidence), with 15 events in the coasting arm and none in the FSH co-trigger arm. There were too few data to determine whether there was a difference between the groups in clinical pregnancy rates (OR 0.92, 95% CI 0.43 to 2.10; one RCT; 102 women; low-quality evidence). This study did not report data suitable for analysis on live birth, multiple pregnancy, or miscarriage, but stated that there was no significant difference between the groups. Coasting versus cabergolineThere were too few data to determine whether there was a difference between the groups in rates of OHSS (OR 1.98, 95% CI 0.09 to 5.68; P = 0.20; I² = 72%; two RCTs; 120 women; very low-quality evidence), with 11 events in the coasting arm and six in the cabergoline arm. The evidence suggested that coasting was associated with lower rates of clinical pregnancy (OR 0.38, 95% CI 0.16 to 0.88; P = 0.02; I² =0%; two RCTs; 120 women; very low-quality evidence), but there were only 33 events altogether. These studies did not report data suitable for analysis on live birth, multiple pregnancy, or miscarriage.

AUTHORS' CONCLUSIONS

There was low-quality evidence to suggest that coasting reduced rates of moderate or severe OHSS more than no coasting. There was no evidence to suggest that coasting was more beneficial than other interventions, except that there was very low-quality evidence from a single small study to suggest that using FSH co-trigger at the time of HCG administration may be better at reducing the risk of OHSS than coasting. There were too few data to determine clearly whether there was a difference between the groups for any other outcomes.

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.

Prevention of Ovarian Hyperstimulation Syndrome: A Review

The following review aims to examine the available evidence to guide best practice in preventing ovarian hyperstimulation syndrome (OHSS). As it stands, there is no single method to completely prevent OHSS. There seems to be a benefit, however, in categorizing women based on their risk of OHSS and individualizing treatments to curtail their chances of developing the syndrome. At present, both Anti-Müllerian Hormone and the antral follicle count seem to be promising in this regard. Both available and upcoming therapies are also reviewed to give a broad perspective to clinicians with regard to management options. At present, we recommend the use of a "step-up" regimen for ovulation induction, adjunct metformin utilization, utilizing a GnRH agonist as an ovulation trigger, and cabergoline usage. A summary of recommendations is also made available for ease of clinical application. In addition, areas for potential research are also identified where relevant.

The prevention of ovarian hyperstimulation syndrome

OBJECTIVE

To review the clinical aspects of ovarian hyperstimulation syndrome and provide recommendations on its prevention.

OPTIONS

Preventative measures, early recognition, and prompt systematic supportive care will help avoid poor outcomes.

OUTCOMES

Establish guidelines to assist in the prevention of ovarian hyperstimulation syndrome, early recognition of the condition when it occurs, and provision of appropriate supportive measures in the correct setting.

EVIDENCE

Published literature was retrieved through searches of Medline, Embase, and the Cochrane Library from 2011 to 2013 using appropriate controlled vocabulary ([OHSS] ovarian hyperstimulation syndrome and: agonist IVF, antagonist IVF, metformin, HCG, gonadotropin, coasting, freeze all, agonist trigger, progesterone) and key words (ovarian hyperstimulation syndrome, ovarian stimulation, gonadotropin, human chorionic gonadotropin, prevention). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies published in English. There were no date restrictions. Searches were updated on a regular basis and incorporated in the guideline to February 2013. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1). Summary Statements 1. The particular follicle-stimulating hormone formulation used for ovarian stimulation does not affect the incidence of ovarian hyperstimulation syndrome. (I) 2. Coasting may reduce the incidence of severe ovarian hyperstimulation syndrome. (III) 3. Coasting for longer than 3 days reduces in vitro fertilization pregnancy rates. (II-2) 4. The use of either luteinizing hormone or human chorionic gonadotropin for final oocyte maturation does not influence the incidence of ovarian hyperstimulation syndrome. (I) 5. There is no clear published evidence that lowering the human chorionic gonadotropin dose will result in a decrease in the rate of ovarian hyperstimulation syndrome. (III) 6. Cabergoline starting from the day of human chorionic gonadotropin reduces the incidence of ovarian hyperstimulation syndrome in patients at higher risk and does not appear to lower in vitro fertilization pregnancy rates. (II-2) 7. Avoiding pregnancy by freezing all embryos will prevent severe prolonged ovarian hyperstimulation syndrome in patients at high risk. (II-2) 8. Pregnancy rates are not affected when using gonadotropin-releasing hormone (GnRH) agonists in GnRH antagonist protocols for final egg maturation when embryos are frozen by vitrification for later transfer. (II-2) Recommendations 1. The addition of metformin should be considered in patients with polycystic ovarian syndrome who are undergoing in vitro fertilization because it may reduce the incidence of ovarian hyperstimulation syndrome. (I-A) 2. Gonadotropin dosing should be carefully individualized, taking into account the patient's age, body mass, antral follicle count, and previous response to gonadotropins. (II-3B) 3. Cycle cancellation before administration of human chorionic gonadatropin is an effective strategy for the prevention of ovarian hyperstimulation syndrome, but the emotional and financial burden it imposes on patients should be considered before the cycle is cancelled. (III-C) 4. Gonadotropin-releasing hormone (GnRH) antagonist stimulation protocols are recommended in patients at high risk for ovarian hyperstimulation syndrome (OHSS). The risk of severe OHSS in patients on GnRH antagonist protocols who have a very robust ovarian stimulation response can be reduced by using a GnRH agonist as a substitute for human chorionic gonadotropin to trigger final oocyte maturation. (I-B) 5. A gonadotropin-releasing hormone (GnRH) antagonist protocol with a GnRH agonist trigger for final oocyte maturation is recommended for donor oocyte and fertility preservation cycles. (III-C) 6. Albumin or other plasma expanders at the time of egg retrieval are not recommended for the prevention of ovarian hyperstimulation syndrome. (I-E) 7. Elective single embryo transfer is recommended in patients at high risk for ovarian hyperstimulation syndrome. (III-C) 8. Progesterone, rather than human chorionic gonadotropin, should be used for luteal phase support. (I-A) 9. Outpatient culdocentesis should be considered for the prevention of disease progression in severe ovarian hyperstimulation syndrome. (II-2B).

Dopamine receptor 2 activation inhibits ovarian vascular endothelial growth factor secretion in vitro: implications for treatment of ovarian hyperstimulation syndrome with dopamine receptor 2 agonists

OBJECTIVE

To ascertain whether vascular endothelial growth factor (VEGF) secretion by luteinized granulosa cells (GCs) is modulated by the dopaminergic system in a dose-dependent fashion and how this is related to the differential efficacy of dopamine receptor 2 (D2)-agonists (D2-ag) in preventing ovarian hyperstimulation syndrome (OHSS).

DESIGN

The relationship between the dopaminergic system and VEGF secretion in luteinized GCs was evaluated. Archived human ovaries were immunostained to characterize D2 expression.

SETTING

University affiliated infertility center.

PATIENT(S)

Premenopausal women and egg donors.

INTERVENTION(S)

Luteinized GCs were cultured with the D2-ag cabergoline. Human ovarian sections were immunostained for D2.

MAIN OUTCOME MEASURE(S)

The VEGF was measured by ELISA and D2 expression was evaluated by In-Cell ELISA. The D2 expression throughout the luteal phase was characterized by immunohistochemistry.

RESULT(S)

The VEGF secretion was decreased by the D2-ag in a dose-dependent fashion. The efficiency of this process was correlated with the amount of D2 expressed by luteinized GCs. A decrease in D2 expression in ovarian sections was observed during the late luteal phase.

CONCLUSION(S)

The efficacy of D2-ags in preventing OHSS might rely on their capacity to inhibit VEGF secretion by luteinized GCs. Because this capacity is dose-dependent, increasing the intraovarian concentration of D2-ags should be explored as a means of increasing the efficacy of these drugs in preventing OHSS.

Oocyte number as a predictor for ovarian hyperstimulation syndrome and live birth: an analysis of 256,381 in vitro fertilization cycles

OBJECTIVE

To investigate the association between oocyte number and the rates of ovarian hyperstimulation syndrome (OHSS) and live birth (LB) in fresh autologous in vitro fertilization (IVF) cycles.

DESIGN

Retrospective cohort study.

SETTING

An academic reproductive medicine practice.

PATIENT(S)

We analyzed data from 256,381 IVF cycles using the 2008-2010 Society for Assisted Reproductive Technology national registry. Patients were divided into five groups based on retrieved oocyte number.

MAIN OUTCOME MEASURE(S)

Rates of OHSS and LB were calculated for each group. A generalized estimating equation (GEE) was used to assess differences in OHSS and LB between groups. Receiver operating characteristic (ROC) curves were used to evaluate oocyte number as a predictor of OHSS and LB.

INTERVENTION(S)

None.

RESULT(S)

The LB rate increased up to 15 oocytes, then plateaued (0-5: 17%, 6-10: 31.7%; 11-15: 39.3%; 16-20: 42.7%; 21-25: 43.8%; and >25 oocytes: 41.8%). However, the rate of OHSS became much more clinically significant after 15 oocytes (0-5: 0.09%; 6-10: 0.37%; 11-15: 0.93%; 16-20: 1.67%; 21-25: 3.03%; and >25 oocytes: 6.34%). These trends remained after adjustment with the use of GEE. ROC curves revealed that although oocyte number is not useful in the prediction of LB, 15 retrieved oocytes is the number that best predicts OHSS risk.

CONCLUSION(S)

Retrieval of >15 oocytes significantly increases OHSS risk without improving LB rate in fresh autologous IVF cycles. In general, less aggressive stimulation protocols should be considered, especially in high-responders, to optimize outcomes.

Scleroderma renal crisis and ovarian hyperstimulation syndrome related to the use of clomiphene in a patient with scleroderma

This paper presented a 28-year-old female with systemic sclerosis who developed scleroderma renal crisis and ovarian hyperstimulation syndrome following clomiphene administration. Urgent therapy including angiotensin-converting enzyme (ACE) inhibitors and supportive care resulted in regression and eventually resolution of all the clinical and laboratory symptoms. Although scleroderma renal crisis is a fatal complication of high-dose corticosteroids, rarely is this seen with the use of ACE inhibitors. This case report aimed to investigate the potential capacity of the selective oestrogen receptor modulator clomiphene to induce scleroderma renal crisis as well as corticosteroids.

The diagnosis and management of ovarian hyperstimulation syndrome

OBJECTIVE

To review the clinical aspects of ovarian hyperstimulation syndrome and provide recommendations on its diagnosis and clinical management.

OUTCOMES

These guidelines will assist in the early recognition and management of ovarian hyperstimulation. Early recognition and prompt systematic supportive care will help avert poor outcomes.

EVIDENCE

Medline, Embase, and the Cochrane database were searched for relevant articles, using the key words "ovarian hyperstimulation syndrome" and "gonadotropins," and guidelines created by other professional societies were reviewed.

VALUES

The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care. Recommendations for practice were ranked according to the method described in that report (Table 1).

RECOMMENDATIONS

1. Once the diagnosis of ovarian hyperstimulation syndrome is made, disease severity should be classified as mild, moderate, severe, or critical. (III-B) 2. The physician prescribing gonadotropins should inform each woman of her personal risk for ovarian hyperstimulation syndrome. (III-A) 3. In areas where patients do not have ready access to physicians familiar with the diagnosis and management of ovarian hyperstimulation syndrome, the physician prescribing gonadotropins should ensure that women are made aware that they should contact a physician or a member of the team within the hospital unit who has relevant experience, should the need arise. (III-B) 4. Outpatient management is recommended for women with mild and moderate ovarian hyperstimulation syndrome. If outpatient management for more severe ovarian hyperstimulation syndrome is to be undertaken, the physician should ensure that the woman is capable of adhering to clinical instructions and that there is a system in place to assess her status every 1 to 2 days. (III-A) 5. Paracentesis should be performed in admitted patients with tense ascites to alleviate their discomfort. (II-2B) 6. Outpatient culdocentesis should be considered for the prevention of disease progression in moderate or severe ovarian hyperstimulation syndrome. (II-2B) 7. Women with severe and critical ovarian hyperstimulation syndrome should be admitted to hospital for intravenous hydration and observation. (III-A) 8. Intravenous hydration should be initiated with a crystalloid solution to prevent hemoconcentration and provide adequate end-organ perfusion. If end-organ perfusion is not maintained with a crystalloid solution, an alternate colloid solution should be administered. (II-2B) 9. Pain relief in admitted patients should be managed with acetaminophen and/or opioid analgesics. (III-B) Non-steroidal anti-inflammatory drugs with antiplatelet properties should not be used. (III-B) 10. Women with severe ovarian hyperstimulation syndrome should be considered for treatment with prophylactic doses of anticoagulants. (II-2B) 11. Critical ovarian hyperstimulation syndrome should be managed by a multidisciplinary team, according to the end organ affected. (III-C).

Update on management of ovarian hyperstimulation syndrome

Ovarian hyperstimulation syndrome (OHSS) is a relatively common complication of ovarian stimulation and can be life threatening. The pathophysiology of OHSS is characterized by increased capillary permeability, leading to leakage of fluid from the vascular compartment, with third-space fluid accumulation and intravascular dehydration. The increased intra-abdominal pressure indicated that OHSS may be considered a compartment syndrome. Vascular endothelial growth factor, also known as vascular permeability factor, has emerged as one of the mediators intrinsic to the development of OHSS. Conventional management is focused on supportive care until the spontaneous resolution of the condition. The standard of care for treatment-monitoring of appropriate clinical parameters, fluid balance management, thrombosis prophylaxis, and ascites treatment-should prevent severe morbidity in most cases. This review will cover inpatient and outpatient management. The potential therapeutic approach targeting the vascular endothelial growth factor system will be discussed.

Coasting (withholding gonadotrophins) for preventing ovarian hyperstimulation syndrome

BACKGROUND

Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic and potentially life threatening condition resulting from excessive ovarian stimulation. Reported incidence varies from 1% to 10% of in vitro fertilization (IVF) cycles. The factors contributing to OHSS have not been completely explained. The release of vasoactive substances secreted by the ovaries under human chorionic gonadotrophin (hCG) stimulation may play a key role in triggering this syndrome. This condition is characterised by a massive shift of fluid from the intra-vascular compartment to the third space resulting in profound intra-vascular depletion and haemoconcentration.

OBJECTIVES

To assess the effect of withholding gonadotrophins (coasting) on the prevention of ovarian hyperstimulation syndrome in assisted reproduction cycles.

SEARCH STRATEGY

For the update of this review we searched the Cochrane Menstrual Disorders and Subfertility Review Group Trials Register (July 2010), CENTRAL (inception to July 2010), MEDLINE (PubMed) (inception to July 2010), and EMBASE (inception to July 2010) for randomised controlled trials (RCTs) in which coasting was used to prevent OHSS.

SELECTION CRITERIA

Only randomised controlled trials (RCTs) in which coasting was used to prevent OHSS were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials and extracted data. Disagreements were resolved by discussion. Study authors were contacted to request additional information or missing data. The intervention comparisons were coasting versus early unilateral follicular aspiration (EUFA), no coasting or other interventions. Statistical analysis was performed in accordance with the Cochrane Menstrual Disorders and Subfertility Group guidelines.

MAIN RESULTS

This updated review identified 16 studies of which four met the inclusion criteria. There was no evidence of a difference in the incidence of moderate and severe OHSS (odds ratio (OR) 0.53, 95% CI 0.23 to 1.23), live birth (OR 0.48, 95% CI 0.14 to 1.62; P = 0.24) or in the clinical pregnancy rate (OR 0.69, 95% CI 0.44 to 1.08) between the groups. Significantly fewer oocytes were retrieved in coasting groups compared with GnRHa (OR -2.44, 95% CI -4.30 to -0.58; P = 0.01) or no coasting (OR -3.92, 95% CI -4.47 to -3.37; P < 0.0001). Data for coasting versus EUFA were not pooled for number of oocytes retrieved due to heterogeneity (I(2) = 87%).

AUTHORS' CONCLUSIONS

There was no evidence to suggest a benefit of using coasting to prevent OHSS compared with no coasting or other interventions.

Coasting (withholding gonadotrophins) for preventing ovarian hyperstimulation syndrome

BACKGROUND

Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic and potentially life threatening condition resulting from excessive ovarian stimulation. Reported incidence varies from 1% to 10% of in vitro fertilization (IVF) cycles. The factors contributing to OHSS have not been completely explained. The release of vasoactive substances secreted by the ovaries under human chorionic gonadotrophin (hCG) stimulation may play a key role in triggering this syndrome. This condition is characterised by a massive shift of fluid from the intra-vascular compartment to the third space resulting in profound intra-vascular depletion and haemoconcentration.

OBJECTIVES

To assess the effect of withholding gonadotrophins (coasting) on the prevention of ovarian hyperstimulation syndrome in assisted reproduction cycles.

SEARCH STRATEGY

For the update of this review we searched the Cochrane Menstrual Disorders and Subfertility Review Group Trials Register (July 2010), CENTRAL (inception to July 2010), MEDLINE (PubMed) (inception to July 2010), and EMBASE (inception to July 2010) for randomised controlled trials (RCTs) in which coasting was used to prevent OHSS.

SELECTION CRITERIA

Only randomised controlled trials (RCTs) in which coasting was used to prevent OHSS were included.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials and extracted data. Disagreements were resolved by discussion. Study authors were contacted to request additional information or missing data. The intervention comparisons were coasting versus early unilateral follicular aspiration (EUFA), no coasting or other interventions. Statistical analysis was performed in accordance with the Cochrane Menstrual Disorders and Subfertility Group guidelines.

MAIN RESULTS

This updated review identified 16 studies of which four met the inclusion criteria. There was no evidence of a difference in the incidence of moderate and severe OHSS (odds ratio (OR) 0.53, 95% CI 0.23 to 1.23), live birth (OR 0.48, 95% CI 0.14 to 1.62; P = 0.24) or in the clinical pregnancy rate (OR 0.69, 95% CI 0.44 to 1.08) between the groups. Significantly fewer oocytes were retrieved in coasting groups compared with GnRHa (OR -2.44, 95% CI -4.30 to -0.58; P = 0.01) or no coasting (OR -3.92, 95% CI -4.47 to -3.37; P < 0.0001). Data for coasting versus EUFA were not pooled for number of oocytes retrieved due to heterogeneity (I(2) = 87%).

AUTHORS' CONCLUSIONS

There was no evidence to suggest a benefit of using coasting to prevent OHSS compared with no coasting or other interventions.

C-reactive protein as the indicator of severity in ovarian hyperstimulation syndrome

BACKGROUND

To establish correlations between laboratory findings and clinical symptoms of moderate and severe ovarian hyperstimulation syndrome (OHSS).

DESIGN

A retrospective study.

SETTING

Department of obstetrics and gynecology, public clinical hospital.

PATIENTS

Nineteen women admitted to the public hospital with a diagnosis of OHSS. The procedure of controlled ovarian stimulation (COH) was performed in the private assisted reproductive technology centre.

METHODS

Blood samples were collected, ultrasound examination of ovaries, abdominal circumference measurement were performed, intravenous crystalloids, plasma expanders such colloids and albumin were given. Correlations between mean laboratory results (haematocrit, c-reactive protein (CRP), white blood count, serum protein, serum albumin), ovarian size in ultrasound examination, abdominal circumference, and amount of albumin and hydroxyethyl starch transfused to the patient were assessed.

RESULTS

Significant correlation was observed between CRP concentration and abdominal circumference measured when the patient was admitted to the department, between CRP concentration and ovarian size measured during ultrasound examination at admission and between CRP concentration and body weight.

CONCLUSIONS

CRP can be a potential candidate to an indicator of OHSS severity.

Ovarian hyperstimulation syndrome: pathophysiology and prevention

PURPOSE

To review and discuss the pathophysiology and prevention strategies for ovarian hyperstimulation syndrome (OHSS), which is a condition that may occur in up to 20% of the high risk women submitted to assisted reproductive technology cycles.

METHODS

The English language literature on these topics were reviewed through PubMed and discussed with emphasis on recent data.

RESULTS

The role of estradiol, luteinizing hormone, human chorionic gonadotropin (hCG), inflammatory mediators, the renin-angiotensin system and vascular endothelial growth factor is discussed in the pathophysiology of OHSS. In addition we consider the prevention strategies, including coasting, administration of albumin, renin-angiotensin system blockage, dopamine agonist administration, non-steroidal anti-inflammatory administration, GnRH antagonist protocols, reducing hCG dosage, replacement of hCG and in vitro maturation of oocytes (IVM).

CONCLUSIONS

Among the many prevention strategies that have been discussed, the current evidence points to the replacement of hCG by GnRH agonists in antagonist cycles and the performance of IVM procedures as the safest approaches.

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.

Cost analysis model of outpatient management of ovarian hyperstimulation syndrome with paracentesis: "tap early and often" versus hospitalization

OBJECTIVE

To compare the cost of two treatment regimens for moderate to severe ovarian hyperstimulation syndrome (OHSS): conservative inpatient versus outpatient management with paracentesis.

DESIGN

A decision-tree mathematical model comparing conservative inpatient versus outpatient management of moderate to severe OHSS was created. The common final pathway of either management was resolution of OHSS. Sensitivity analyses were performed over the range of variables.

MAIN OUTCOME MEASURE(S)

Total management cost of OHSS.

RESULT(S)

The cost of conservative therapy including first-tier complications was $10,099 (range $9,655-$15,044). The cost of outpatient management with paracentesis was $1954 (range $788-$12,041). This resulted in an estimated cost savings of $8145 with outpatient management with paracentesis. One-way sensitivity analyses were performed. Varying the probability of admission after outpatient treatment still indicated that outpatient treatment was the most cost-effective (probability = 1.0, cost = $6110). Varying the duration of hospitalization with primary inpatient treatment was equal to outpatient treatment costs only at a stay of 0.71 days or shorter.

CONCLUSION(S)

Our model suggests early outpatient paracentesis for moderate to severe OHSS is the most cost-effective management plan when compared with traditional conservative inpatient therapy. The cost savings for outpatient management persisted throughout a variety of outcome probabilities.

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.

Clinical biochemistry of assisted conception

Assisted reproductive technology has shown rapid advancement since the birth of the first 'test-tube' baby in Oldham, UK, in 1978. Since April 2005, women between the ages of 23 and 39, who meet the described eligibility criteria, are able to get one free in vitro fertilization cycle funded by the National Health Service. Private treatment costs anything from pound4000 to pound8000 for a single cycle of treatment. Almost 15% of the couples in UK are affected by fertility problems and undergo detailed investigations before being offered assisted conception. Assisted reproduction is the collective name for treatments designed to lead to conception by means other than sexual intercourse. These include intrauterine insemination, in vitro fertilization, intracytoplasmic sperm injection and gamete donation. This review is intended to summarize the principles of assisted conception and examine the role of the biochemistry laboratory in: (A) the diagnosis and subsequent management of ovulatory disorders; (B) assessing ovarian reserve before initiating fertility treatment and (C) monitoring fertility treatment. It touches on the screening of potential gamete donors and follow-up of children born after assisted conception. This article was prepared at the invitation of the Clinical Sciences Reviews Committee of the Association of Clinical Biochemistry.