Calcium gluconate infusion is as effective as the vascular endothelial growth factor antagonist cabergoline for the prevention of ovarian hyperstimulation syndrome

Comparison of the Effectiveness of Various Medicines in the Prevention of Ovarian Hyperstimulation Syndrome: A Network Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Previous studies have described the effects of different drugs in preventing ovarian hyperstimulation syndrome (OHSS). However, the efficacies of those drugs in preventing OHSS remain inconclusive.

METHODS

We searched the PubMed, Web of Science, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) databases. A network meta-analysis of randomized controlled trials (RCTs) was performed up to August 2021. We investigated the following drugs in our study: aspirin, albumin, metformin, calcium, cabergoline, quinagolide, letrozole, hydroxyethyl starch (HES), and glucocorticoids. The primary outcome was the incidence rate of moderate-to-severe OHSS, with the results presented as risk ratios (RRs) with 95% confidence intervals (CIs).

RESULTS

The incidence of moderate-to-severe OHSS was significantly reduced by calcium administration (risk ratios [RR] 0.14, 95% confidence interval [CI]: 0.04, 0.46) (grade: high), HES (RR 0.25, 95% CI 0.07, 0.73) (grade: high), and cabergoline (RR 0.43, 95% CI 0.24, 0.71) (grade: moderate). The surface under the cumulative ranking curve (SUCRA) indicated that calcium (SUCRA, 92.4%) was the most effective intervention for preventing moderate-to-severe OHSS. These drugs were safe and did not affect clinical pregnancy, miscarriage, or live birth rates.

CONCLUSION

Calcium, HES, and cabergoline could effectively and safely prevent moderate-to-severe OHSS, with calcium as the most effective intervention.

Cabergoline versus calcium infusion in the prevention of ovarian hyperstimulation syndrome: a randomised controlled study

The aim of this study was to compare the efficacy of calcium infusion versus cabergoline in the prevention of ovarian hyperstimulation syndrome (OHSS) in IVF patients at high risk for OHSS. One hundred and seventy patients who were stimulated using the long luteal GnRH agonist protocol and at high risk for developing OHSS were randomised in a 1:1 ratio to cabergoline group and calcium gluconate group. In cabergoline group, 0.5 mg of cabergoline was administered once daily p.o. for eight days starting on the day of HCG administration. In calcium gluconate group, intravenous calcium gluconate (10%, 10 ml in 200 ml of physiologic saline) was administered daily for four days starting on the day of ovum pickup. Six patients in cabergoline group and eight patients in calcium gluconate group developed moderate OHSS. One patient in each group developed severe OHSS. The incidence of moderate/severe OHSS was comparable between both groups (8.24% vs. 10.59%, p value  =  .599, OR = 0.76, 95% CI [0.269-2.138]). The implantation, clinical and ongoing pregnancy rates were similar in the two groups (16.91% vs. 15.84%, p = .771, 35.29% vs. 32.94%, p = .746, and 30.59% vs. 28.24%, p = .736, respectively). In conclusion, calcium infusion and cabergoline have comparable effectiveness in the prevention of OHSS. Both drugs are well tolerated, cheap and have no adverse effects on the reproductive outcomes of IVF cycle.Clinical trial registration: The trial was registered on clinical trials.gov database [NCT02875587].Impact StatementWhat is already known on this subject? The effectiveness of cabergoline in the prevention of OHSS in IVF patients at high risk for OHSS is confirmed by overwhelming scientific evidence. Calcium infusion is a novel strategy for prevention of OHSS. Few studies reported the use of calcium infusion in the prevention of OHSS. A retrospective study and a randomised controlled study revealed that calcium infusion reduces the incidence of OHSS. Moreover, a quasi-randomised study revealed that calcium infusion is as effective as cabergoline in the prevention of OHSS.What the results of this study add? Calcium infusion and cabergoline have comparable effectiveness in the prevention of OHSS. Both drugs are well tolerated, cheap and have no adverse effects on the reproductive outcomes of IVF cycle.What the implications are of these findings for clinical practice and/or further research? Calcium infusion should be used to minimise the incidence of OHSS in IVF patients at high risk for OHSS.

Dopamine agonists for preventing ovarian hyperstimulation syndrome

BACKGROUND

Ovarian hyperstimulation syndrome (OHSS) is a potentially serious complication of ovarian stimulation in assisted reproduction technology (ART). It is characterised by enlarged ovaries and an acute fluid shift from the intravascular space to the third space, resulting in bloating, increased risk of venous thromboembolism, and decreased organ perfusion. Most cases are mild, but forms of moderate or severe OHSS appear in 3% to 8% of in vitro fertilisation (IVF) cycles. Dopamine agonists were introduced as a secondary prevention intervention for OHSS in women at high risk of OHSS undergoing ART treatment.  OBJECTIVES: To assess the effectiveness and safety of dopamine agonists in preventing OHSS in women at high risk of developing OHSS when undergoing ART treatment.

SEARCH METHODS

We searched the following databases from inception to 4 May 2020: Cochrane Gynaecology and Fertility Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL, and PsycINFO for randomised controlled trials (RCTs) assessing the effect of dopamine agonists on OHSS rates. We also handsearched reference lists and grey literature.

SELECTION CRITERIA

We considered RCTs for inclusion that compared dopamine agonists with placebo/no intervention or another intervention for preventing OHSS in ART. Primary outcome measures were incidence of moderate or severe OHSS and live birth rate. Secondary outcomes were rates of clinical pregnancy, multiple pregnancy, miscarriage, and adverse events.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles, abstracts, and full texts of publications; selected studies; extracted data; and assessed risk of bias. We resolved disagreements  by consensus. We reported pooled results as odds ratios (OR) and 95% confidence interval (CI) by the Mantel-Haenszel method. We applied GRADE criteria to judge overall quality of the evidence.

MAIN RESULTS

The search identified six new RCTs, resulting in 22 included RCTs involving 3171 women at high risk of OHSS for this updated review. The dopamine agonists were cabergoline, quinagolide, and bromocriptine. Dopamine agonists versus placebo or no intervention Dopamine agonists probably lowered the risk of moderate or severe OHSS compared to placebo/no intervention (OR 0.32, 95% CI 0.23 to 0.44; 10 studies, 1202 participants; moderate-quality evidence). This suggests that if the risk of moderate or severe OHSS following placebo/no intervention is assumed to be 27%, the risk following dopamine agonists would be between 8% and 14%. We are uncertain of the effect of dopamine agonists on rates of live birth (OR 0.96, 95% CI 0.60 to 1.55; 3 studies, 362 participants; low-quality evidence). We are also uncertain of the effect of dopamine agonists on clinical pregnancy, multiple pregnancy, miscarriage  or adverse events (very low to low-quality evidence). Dopamine agonists plus co-intervention versus co-intervention Dopamine agonist plus co-intervention (hydroxyethyl starch, human albumin, or withholding ovarian stimulation 'coasting') may decrease the risk of moderate or severe OHSS compared to co-intervention (OR 0.48, 95% CI 0.28 to 0.84; 4 studies, 748 participants; low-quality evidence). Dopamine agonists may improve rates of live birth (OR 1.21, 95% CI 0.81 to 1.80; 2 studies, 400 participants; low-quality evidence). Dopamine agonists may improve rates of clinical pregnancy and miscarriage, but we are uncertain if they improve rates of multiple pregnancy  or adverse events (very low to low-quality evidence). Dopamine agonists versus other active interventions We are uncertain if cabergoline improves the risk of moderate or severe OHSS compared to human albumin (OR 0.21, 95% CI 0.12 to 0.38; 3 studies, 296 participants; very low-quality evidence), prednisolone (OR 0.27, 95% CI 0.05 to 1.33; 1 study; 150 participants; very low-quality evidence), hydroxyethyl starch (OR 2.69, 95% CI 0.48 to 15.10; 1 study, 61 participants; very low-quality evidence), coasting (OR 0.42, 95% CI 0.18 to 0.95; 3 studies, 320 participants; very low-quality evidence), calcium infusion (OR 1.83, 95% CI 0.88 to 3.81; I² = 81%; 2 studies, 400 participants; very low-quality evidence), or diosmin (OR 2.85, 95% CI 1.35 to 6.00; 1 study, 200 participants; very low-quality evidence). We are uncertain of the effect of dopamine agonists on rates of live birth (OR 1.08, 95% CI 0.73 to 1.59; 2 studies, 430 participants; low-quality evidence). We are uncertain of the effect of dopamine agonists on clinical pregnancy, multiple pregnancy or miscarriage (low to moderate-quality evidence). There were no adverse events reported.

AUTHORS' CONCLUSIONS

Dopamine agonists probably reduce the incidence of moderate or severe OHSS compared to placebo/no intervention, while we are uncertain of the effect on adverse events and pregnancy outcomes (live birth, clinical pregnancy, miscarriage). Dopamine agonists plus co-intervention may decrease moderate or severe OHSS rates compared to co-intervention only, but we are uncertain whether dopamine agonists affect pregnancy outcomes. When compared to other active interventions, we are uncertain of the effects of dopamine agonists on moderate or severe OHSS and pregnancy outcomes.

Ovarian Hyperstimulation Syndrome: A Narrative Review of Its Pathophysiology, Risk Factors, Prevention, Classification, and Management

Ovarian hyperstimulation syndrome (OHSS) is a serious complication of ovulation induction that usually occurs after gonadotropin stimulation, followed by human chorionic gonadotropin administration, for infertility treatment. The existing knowledge about the pathophysiology, risk factors, and primary and secondary methods for the prevention of OHSS is reviewed in this manuscript. The clinical manifestations and characteristics of mild, moderate, severe, and critical forms of the syndrome are defined. The methods of handling affected cases as outpatient or in-hospital management methods as well as indications for hospitalization are summarized in this review. The clinical and biochemical routes of assessing and monitoring hospitalized patients with OHSS, various drugs and medical treatment strategies including indications for aspiration of the ascitic fluid and pleural effusion, and also rare indications for surgery are briefly explained in this article. Severe OHSS, which two decades ago was considered an iatrogenic life-threatening condition, can now be effectively prevented or managed during the early stages. An OHSS-free clinic can be established nowadays by carefully considering the endocrinology of ovulation and using appropriate and dose-adjusted pharmaceutical agents, which are summarized and discussed in this review.

Combined modalities for the prevention of ovarian hyperstimulation syndrome following an excessive response to stimulation

Although the classification and management of ovarian hyperstimulation syndrome (OHSS) are well described in the literature, little attention has been given to modalities that aim to prevent its occurrence. In this retrospective study, we sought to investigate whether a combination of modalities in addition to GnRH agonist triggering in GnRH antagonist cycles could result in better prevention of OHSS. The study included 170 hyperresponder patients who were stimulated with GnRH antagonist protocol and were triggered with GnRH agonist for final oocyte maturation. Freeze all embryos was performed in all patients. The intervention group included treatment with dopamine agonist and restarting the GnRH antagonist. Of the 170 patients included, 63 were included in the intervention group. Compared to no intervention, women in the intervention group were more likely to have: menses within 7 days of the oocyte retrieval, smaller ovarian diameter, the absence of free pelvic fluid, less hemoconcentration and higher serum sodium levels. It can be concluded that combining other modalities in addition to triggering with GnRH agonist in GnRH antagonist cycles, results in targeting several pathways that lead to OHSS and result in rapid resolution of signs of ovarian hyperstimulation.

Dopamine agonists for preventing ovarian hyperstimulation syndrome

BACKGROUND

Ovarian hyperstimulation syndrome (OHSS) is a potentially serious complication of ovarian stimulation in assisted reproduction technology (ART). It is characterised by enlarged ovaries and an acute fluid shift from the intravascular space to the third space, resulting in bloating, increased risk of venous thromboembolism and decreased organ perfusion. Most cases are mild, but forms of moderate or severe OHSS appear in 3% to 8% of in vitro fertilisation (IVF) cycles. The dopamine agonist cabergoline was introduced as a secondary prevention intervention for OHSS in women at high risk of OHSS undergoing ART treatment. As cabergoline seemed to be effective in preventing OHSS, other types of dopamine agonists, such as quinagolide and bromocriptine, have since been studied in ART to prevent OHSS.

OBJECTIVES

To assess the effectiveness and safety of dopamine agonists in preventing OHSS in high-risk women undergoing ART treatment.

SEARCH METHODS

We searched several databases from inception to August 2016 (Cochrane Gynaecology and Fertility Specialised Register of trials, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, CINAHL, PsycINFO, Clinicaltrials.gov and the World Health Organization International Trials Registry Platform (ICTRP)) for randomised controlled trials (RCTs) assessing the effect of dopamine agonist in preventing OHSS. We handsearched the reference lists of relevant studies.

SELECTION CRITERIA

We considered RCTs which compared dopamine agonists with placebo/no intervention or another intervention for preventing OHSS in high-risk women for inclusion. Primary outcome measures were incidence of moderate or severe OHSS and live birth rate. Secondary endpoints were clinical pregnancy rate, multiple pregnancy rate, miscarriage rate and any other adverse effects of the treatment.

DATA COLLECTION AND ANALYSIS

Two authors independently screened titles, abstracts and full texts of publications, selected studies, extracted data and assessed risk of bias. We resolved any disagreements by consensus. We reported pooled results as odds ratios (OR) and 95% confidence interval (95% CI) by the Mantel-Haenszel method. In addition, we graded the overall quality of the evidence using GRADE criteria.

MAIN RESULTS

The search identified 14 new RCTs since the last published version of this review, resulting in 16 included RCTs involving 2091 high-risk women for this updated review. They evaluated three types of dopamine agonists: cabergoline, quinagolide and bromocriptine.When compared with placebo or no intervention, dopamine agonists seemed effective in the prevention of moderate or severe OHSS (OR 0.27, 95% CI 0.19 to 0.39; 1022 participants; 8 studies; I² = 0%; moderate quality evidence). This suggests that if 29% of women undergoing ART experience moderate or severe OHSS, the use of dopamine agonists will lower this to 7% to 14% of women. There was no evidence of a difference in live birth rate, clinical pregnancy rate, multiple pregnancy rate or miscarriage rate (very low to moderate quality evidence). However, taking dopamine agonists (especially quinagolide) may increase the incidence of adverse events such as gastrointestinal adverse effects (OR 4.54, 95% CI 1.49 to 13.84; 264 participants; 2 studies; I² = 49%, very low quality evidence).When we compared dopamine agonist plus co-intervention with co-intervention, there was no evidence of a difference in the outcomes of moderate or severe OHSS, live birth rate, clinical pregnancy rate, miscarriage rate or adverse events. The co-interventions were hydroxyethyl starch (two RCTs) and albumin (one RCT).Cabergoline was associated with a lower risk of moderate or severe OHSS compared with human albumin (OR 0.21, 95% CI 0.12 to 0.38; 296 participants; 3 studies; I² = 72%). However, there was no evidence of a difference between cabergoline and hydroxyethyl starch, coasting (withholding any more ovarian stimulation for a few days) or prednisolone. There was an increased clinical pregnancy rate in the cabergoline group when cabergoline was compared with coasting (OR 2.65, 95% CI 1.13 to 6.21; 120 participants; 2 studies; I² = 0%). In other respects, there was no evidence of a difference in clinical pregnancy rate, multiple pregnancy rate or miscarriage rate between cabergoline and other active interventions.The quality of the evidence between dopamine agonist and placebo or no intervention ranged from very low to moderate, mainly due to poor reporting of study methods (mostly a lack of details on randomisation or blinding) and serious imprecision for some comparisons.

AUTHORS' CONCLUSIONS

Dopamine agonists appear to reduce the incidence of moderate or severe OHSS in women at high risk of OHSS (moderate quality evidence). If a fresh embryo transfer is performed, the use of dopamine agonists does not affect the pregnancy outcome (live birth rate, clinical pregnancy rate and miscarriage rate) (very low to moderate quality evidence). However, dopamine agonists might increase the risk of adverse events, such as gastrointestinal symptoms. Further research should focus on dose-finding, comparisons with other effective treatments and consideration of combination treatments. Therefore, large, well-designed and well-executed RCTs that involve more clinical endpoints (e.g., live birth rate) are necessary to further evaluate the role of dopamine agonists in OHSS prevention.

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.

Volume expanders for the prevention of ovarian hyperstimulation syndrome

BACKGROUND

Ovarian hyperstimulation syndrome (OHSS) is a serious and potentially fatal complication of ovarian stimulation which affects 1% to 14% of all in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) cycles. A number of clinical studies with conflicting results have reported on the use of plasma expanders such as albumin, hydroxyethyl starch (HES), mannitol, polygeline and dextran as a possible intervention for the prevention of OHSS. Women with very high estradiol levels, high numbers of follicles or oocytes retrieved, and women with polycystic ovary syndrome (PCOS), are at particularly high risk of developing OHSS. Plasma expanders are not commonly used nowadays in ovarian hyperstimulation. This is mainly because clinical evidence on their effectiveness remains sparse, because of the low incidence of moderate and severe ovarian hyperstimulation syndrome (OHSS) and the simultaneous introduction of mild stimulation approaches, gonadotropin-releasing hormone (GnRH) antagonist protocols and the freeze-all strategy for the prevention of OHSS.

OBJECTIVES

To review the effectiveness and safety of administration of volume expanders for the prevention of moderate and severe ovarian hyperstimulation syndrome (OHSS) in high-risk women undergoing IVF or ICSI treatment cycles.

SEARCH METHODS

We searched databases including the Cochrane Gynaecology and Fertility Group Specialised Register of controlled trials, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase and trial registers to September 2015; no date restrictions were used as new comparators were included in this search. The references of relevant publications were also searched. We attempted to contact authors to provide or clarify data that were unclear from trial or abstract reports.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing volume expanders versus placebo or no treatment for the prevention of OHSS in high-risk women undergoing ovarian hyperstimulation as part of any assisted reproductive technique.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected the studies, assessed risk of bias and extracted relevant data. The primary review outcome was moderate or severe OHSS. Other outcomes were live birth, pregnancy and adverse events. We combined data to calculate pooled Peto odds ratios (ORs) and 95% confidence intervals (CIs) for each intervention. Statistical heterogeneity was assessed using the I(2) statistic. We assessed the overall quality of the evidence for each comparison, using GRADE methods.

MAIN RESULTS

We included nine RCTs (1867 women) comparing human albumin (seven RCTs) or HES (two RCTs) or mannitol (one RCT) versus placebo or no treatment for prevention of OHSS. The evidence was very low to moderate quality for all comparisons. The main limitations were imprecision, poor reporting of study methods, and failure to blind outcome assessment.There was evidence of a beneficial effect of intravenous albumin on OHSS, though heterogeneity was substantial (Peto OR 0.67 95% CI 0.47 to 0.95, seven studies, 1452 high risk women; I² = 69%, very low quality evidence) . This suggests that if the rate of moderate or severe OHSS with no treatment is 12%, it will be about 9% (6% to12%) with the use of intravenous albumin. However, there was evidence of a detrimental effect on pregnancy rates (Peto OR 0.72 95% CI 0.55 to 0.94, I² = 42%, seven studies 1069 high risk women, moderate quality evidence). This suggests that if the chance of pregnancy is 40% without treatment, it will be about 32% (27% to 38%) with the use of albumin.There was evidence of a beneficial effect of HES on OHSS (Peto OR 0.27 95% CI 0.12 to 0.59, I² = 0%, two studies, 272 women, very low quality evidence). This suggests that if the rate of moderate or severe OHSS with no treatment is 16%, it will be about 5% (2% to 10%) with the use of HES. There was no evidence of an effect on pregnancy rates (Peto OR 1.20 95% CI 0.49 to 2.93, one study, 168 women, very low quality evidence).There was evidence of a beneficial effect of mannitol on OHSS (Peto OR 0.38, 95% CI 0.22 to 0.64, one study, 226 women with PCOS, low quality evidence). This means that if the risk of moderate or severe OHSS with no treatment is 52%, it will be about 29% (19% to 41%) with mannitol. There was no evidence of an effect on pregnancy rates (Peto OR 0.85 95% CI 0.47 to 1.55; one study, 226 women, low quality evidence).Live birth rates were not reported in any of the studies. Adverse events appeared to be uncommon, but were too poorly reported to reach any firm conclusions.

AUTHORS' CONCLUSIONS

Evidence suggests that the plasma expanders assessed in this review (human albumin, HES and mannitol) reduce rates of moderate and severe OHSS in women at high risk. Adverse events appear to be uncommon, but were too poorly reported to reach any firm conclusions, and there were no data on live birth. However, there was evidence that human albumin reduces pregnancy rates. While there was no evidence that HES, or mannitol had any influence on pregnancy rates, the evidence of effectiveness was based on very few trials which need to be confirmed in additional, larger randomised controlled trials (RCTs) before they should be considered for routine use in clinical practice.

Pharmacologic Interventions in Preventing Ovarian Hyperstimulation Syndrome: A Systematic Review and Network Meta-Analysis

Ovarian hyperstimulation syndrome (OHSS) is a severe iatrogenic complication of controlled ovarian stimulation. Randomised controlled trials (RCTs) have proven several pharmacologic interventions to be effective in OHSS prevention, but these trials have seldom compared multiple drugs. We identified randomised controlled trials (RCTs) through June 2015 by searching databases and compared 11 intervention strategies in preventing OHSS (primary outcome) and their influence on pregnancy rate (secondary outcome). A network meta-analysis was used to evaluate the relative effectiveness among treatments and to create a rank probability table. Thirty-one RCTs were identified, including 7181 participants. Five pharmacologic interventions were superior to placebo in decreasing OHSS incidence: aspirin [relative risk (RR) 0.07, 95% credible interval (CrI) 0.01-0.30, p < 0.05], intravenous (IV) calcium [RR 0.11, 95% CrI 0.02-0.54, p < 0.05], cabergoline [RR 0.17, 95% CrI 0.06-0.43, p < 0.05], metformin [RR 0.20, 95% CrI 0.07-0.59, p < 0.05] and IV hydroxyethyl starch (HES) [RR 0.26, 95% CrI 0.05-0.99, p < 0.05]. The rank probability demonstrated aspirin (Rank 1: 36%) and IV calcium (Rank 1: 35%) to be the most efficacious. Additionally, albumin might decrease the pregnancy rate when compared with placebo [RR 0.85, 95% CI 0.74-0.97, p < 0.05]. This conclusion provides a relative standard and objective reference for choosing an OHSS prophylactic agent.

Cabergoline for preventing ovarian hyperstimulation syndrome in women at risk undergoing in vitro fertilization/intracytoplasmic sperm injection treatment cycles: A randomized controlled study

Background:

Ovarian hyperstimulation syndrome (OHSS) is the most serious and potentially life-threatening iatrogenic complication associated with ovarian stimulation during assisted reproductive technology protocols. The aim of this study was to evaluate the role of dopamine agonist as a preventive strategy of OHSS in women at high risk in in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) treatment cycles.

Methods:

Seventy women at risk to develop OHSS undergoing IVF/ICSI treatment cycle were included. The study group received 0.5 mg of cabergoline for 8 days from the day of human chorionic gonadotropin administration in comparison to those who undergo no treatment for the prevention of OHSS. The reduction of the incidence of OHSS was the primary outcome.

Results:

The actual incidence of OHSS was 8.33% in the cabergoline group and 20.58% in the control group. Thus, the incidence of OHSS was significantly reduced, by almost 60%, in the cabergoline group in comparison with the control group (relative ratios: 0.4, 95% confidence interval: 0.18–0.79).

Conclusion:

Prophylactic treatment with the dopamine agonist, cabergoline, reduces the incidence of OHSS in women at high risk undergoing IVF/ICSI treatment. However, the effects of cabergoline on important outcomes, namely, live birth, miscarriage, and congenital abnormalities are still uncertain.

Consensus statement on prevention and detection of ovarian hyperstimulation syndrome

BACKGROUND

Ovarian hyperstimulation syndrome is an important condition with considerable morbidity and a small risk of mortality, which most commonly results as an iatrogenic condition following follicular stimulation of the ovaries.

AIM

To produce evidence-based and consensus statements on the prevention and detection of ovarian hyperstimulation syndrome (OHSS).

METHOD

The CREI Consensus Group met in 2008 and identified issues for inclusion and review. Review of the available evidence was conducted and consensus statements prepared. Areas of dissent of expert opinion and for further research were noted.

RESULTS

The group considered that there is a need for standardisation of the definition and classification of the clinical syndrome of OHSS to allow further conclusive research. Interventions with evidence of effect in reducing OHSS include the use of metformin in women with PCOS, use of GnRH antagonist rather than GnRH agonist and use of GnRH agonist triggers in GnRH antagonist stimulation cycles. The consensus view was that reducing the dose of FSH, freezing all embryos and transferring a single embryo were appropriate interventions to reduce OHSS. Agreement could not be reached on coasting, the lowest number of oocytes to consider freezing all embryos and management after cancellation of oocyte collection.

CONCLUSION

OHSS is a serious condition for which there are a number of proven preventative strategies. OHSS is an area requiring ongoing research and development of a universally agreed definition will allow development of optimal prevention strategies and facilitate improved early detection of women at risk.

Ovarian hyperstimulation syndrome: pathophysiology, staging, prediction and prevention

OBJECTIVE

To identify, appraise and summarize the current evidence regarding the pathophysiology, staging, prediction and prevention of ovarian hyperstimulation syndrome (OHSS).

METHODS

Two comprehensive systematic reviews were carried out: one examined methods of predicting either high ovarian response or OHSS and the other examined interventions aimed at reducing the occurrence of OHSS. Additionally, we describe the related pathophysiology and staging criteria.

RESULTS

Seven studies examining methods of predicting OHSS and eight more examining methods of predicting high ovarian response to controlled ovarian stimulation were included. Current evidence shows that the best methods of predicting high response are antral follicle count and anti-Müllerian hormone levels, and that a high ovarian response (examined by the number of large follicles, estradiol concentration or the number of retrieved oocytes) is the best method of predicting the occurrence of OHSS. Ninety-seven randomized controlled trials examining the effect of several interventions for reducing the occurrence of OHSS were included. There was high-quality evidence that replacing human chorionic gonadotropin by gonadotropin-releasing hormone agonists or recombinant luteinizing hormone, and moderate-quality evidence that antagonist protocols, dopamine agonists and mild stimulation, reduce the occurrence of OHSS. The evidence for the effect of the other interventions was of low/very low quality. Additionally, we identified and described 12 different staging criteria.

CONCLUSIONS

There are useful predictive tools and several preventive interventions aimed at reducing the occurrence of OHSS. Acknowledging and understanding them are of crucial importance for planning the treatment of, and, ultimately, eliminating, OHSS while maintaining high pregnancy rates.