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

Embryo freezing for preventing ovarian hyperstimulation syndrome

BACKGROUND

Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic potentially life threatening condition resulting from an excessive ovarian stimulation. Its reported incidence varies from one percent to ten percent of in vitro fertilization (IVF) cycles. The factors leading to this syndrome have not been completely explained. It seems likely that the release of vasoactive substances, secreted by the ovaries under human chorionic gonadotropin (hCG) stimulation plays a key role in triggering this syndrome. The hallmark of this condition, is a massive shift of fluid from the intra-vascular compartment to the third space resulting in profound intra-vascular depletion and haemoconcentration.

OBJECTIVES

To evaluate (i) the effectiveness of cryopreservation (embryo freezing) for the prevention of OHSS when compared with human intra-venous albumin infusion (ii) the effectiveness of the elective cryopreservation (embryo freezing ) of all embryos for the prevention of OHSS when compared with fresh embryo transfer.

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorders and Subfertility Review Group specialised register of controlled trials up to April 2007. In addition, MEDLINE (PUBMED 1985 to March 2007), EMBASE (1985 to April 2007), CINAHL (1985 to March 2007) and the National Research Register (April 2007) were searched.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in which either human intra-venous albumin or cryopreservation of all embryos were used as a therapeutic approach to OHSS were included. The women were women of reproductive age who were down regulated by gonadotrophin-releasing hormone-analogue (GnRH-a), undergoing superovulation in in vitro fertilization and or intra-cytoplasmic sperm injection (IVF and or ICSI) cycles.

DATA COLLECTION AND ANALYSIS

Two review authors, Mr N.N. Amso (NNA) and Dr A. D'Angelo (ADA) scanned the titles and the abstracts of the reports identified by electronic searching in order to find relevant papers. One reviewer (ADA) obtained copies of the full text articles and made copies for the other reviewer (NNA) in which details of authors, institution, results and discussion were removed in order to assess their eligibility for inclusion . Disagreements were resolved by discussion. Additional information on the trial methodology or data were requested by writing to the corresponding authors directly. The interventions compared were cryopreservation (embryo freezing) versus intra-venous human albumin administration and elective cryopreservation of all embryos versus fresh embryo transfer. The primary outcomes were: incidence of moderate and severe OHSS versus nil and or mild OHSS, clinical pregnancies and or woman. The secondary outcomes were: number of oocytes retrieved, number of oocytes fertilized, number of embryos transferred, number of embryos frozen, multiple pregnancy rate, live birth rate, number of women admitted to the hospital as inpatient or outpatient and time to the next menstrual period (resolution time). Statistical analysis was performed in accordance with the Cochrane Menstrual Disorders and Subfertility Group guidelines.

MAIN RESULTS

No new studies were identified for inclusion in the update therefore the of seventeen studies originally identified in the review published issue 2, 2002. It therefore remains that two studies of which met our inclusion criteria one study was included where cryopreservation (embryo freezing) was compared with intra-venous human albumin administration (Shaker 1996) and one study was included where elective cryopreservation of all embryos was compared with fresh embryo transfer (Ferraretti 1999). When cryopreservation was compared with intra-venous human albumin administration no difference was found in all the outcomes examined between the two groups. When elective cryopreservation of all embryos was compared with fresh embryo transfer no difference was found in all the outcomes examined between the two groups.

AUTHORS' CONCLUSIONS

This updated of the review (D'Angelo 2002) has showed that there is insufficient evidence to support routine cryopreservation and insufficient evidence for the relative merits of intra-venous albumin versus cryopreservation.

Vascular endothelial growth factor production by circulating immune cells is elevated in ovarian hyperstimulation syndrome

BACKGROUND

Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic disease manifesting itself by ovarian enlargement and massive ascites with increased peritoneal capillary permeability. Although vascular endothelial growth factor (VEGF) is considered to play the main role in developing OHSS, its precise mechanism remains unclear. In this study, we examined possible roles of circulating immune cells in the pathogenesis of OHSS.

METHODS

Peripheral blood mononuclear cells (PBMC) and plasma were collected from healthy non-pregnant volunteers and from patients receiving ovulation induction for IVF. PBMC were cultured for 48 h. Plasma and/or medium concentrations of VEGF, estradiol and progesterone were measured using enzyme-linked immunosorbent assay and radioimmunoassay kits.

RESULTS

VEGF production by cultured PBMC and plasma concentrations of VEGF taken from patients with early onset OHSS (n = 12) were significantly higher than those in non-pregnant volunteers and patients without OHSS whose oocyte retrieval rates were similar to that of OHSS patients. OHSS patients were further classified into a high plasma VEGF concentration group and a high culture medium VEGF group. There was no significant correlation among VEGF production by PBMC and plasma concentration of VEGF, estradiol or progesterone.

CONCLUSION

Although mechanistic evidence has not been provided, our study does provide new evidence to suggest that circulating immune cells are involved in the pathogenesis of OHSS via VEGF production.

Incidence and prediction of ovarian hyperstimulation syndrome in women undergoing gonadotropin-releasing hormone antagonist in vitro fertilization cycles

OBJECTIVE

To determine the incidence of ovarian hyperstimulation syndrome (OHSS) in a large series of GnRH antagonist-stimulated cycles and to assess the predictive value of E2 and the number of follicles on the day of hCG administration.

DESIGN

Prospective cohort study of women undergoing IVF treatment with a GnRH antagonist protocol over a 2-year period.

SETTING

Tertiary university hospital.

PATIENT(S)

One thousand eight hundred one patients who underwent 2,524 cycles.

INTERVENTION(S)

Multifollicular ovarian stimulation with recombinant FSH and GnRH antagonist for IVF-ICSI treatment.

MAIN OUTCOME MEASURE(S)

Incidence of OHSS in GnRH antagonist cycles, predictive value of E2, and number of follicles on the day of hCG for OHSS occurrence.

RESULT(S)

Fifty-three patients were hospitalized because of OHSS (2.1%; 95% confidence interval [CI]:1.6-2.8). Early OHSS presented in 31 patients (1.2%; 95% CI: 0.9-1.8), whereas the late type was a complication in 22 patients (0.9%; 95% CI: 0.5-1.3). Late OHSS cases compared with the early OHSS cases always occurred in a pregnancy cycle (100% vs. 40%); had higher probability of being severe (72.7% vs. 42%), and more often were related to a multiple pregnancy (40% vs. 0). Receiver operating characteristic curve analysis for several E2 concentrations and number of follicles with a diameter of > or =11 mm revealed that the predictive value of the optimal threshold of > or =13 follicles (85.5% sensitivity; 69% specificity) was statistically significantly superior to the optimal threshold of 2,560 ng/L for E2 concentrations (53% sensitivity, 77% specificity) in identifying patients at risk for OHSS. Considering that severe OHSS represents the most clinically significant pattern, the combination of a threshold of > or =18 follicles and/or E2 of > or =5,000 ng/L yields a 83% sensitivity rate with a specificity as high as 84% for the severe OHSS cases.

CONCLUSION(S)

Clinically significant OHSS still remains a limitation of multifollicular ovarian stimulation for IVF even with the use of GnRH antagonist protocols. The number of follicles can discriminate the patients who are at risk for developing OHSS, whereas E2 concentrations are less reliable for the purpose of prediction. There is more than ever an urgent need for alternative final oocyte maturation-triggering medication.

Activated protein C and the ovarian hyperstimulation syndrome: Possible therapeutic implications

Given the efficacy and safety of recombinant human activated protein C (rhAPC) in the systemic inflammatory response syndrome (SIRS), this study was designed to review the evidence for rhAPC as a possible therapeutic option in the treatment of severe ovarian hyperstimulation syndrome (OHSS). SIRS, like OHSS, is a proinflammatory and prothrombotic disorder whose cornerstone is endothelial dysfunction in which protein C deficiency is a frequent occurrence. Recently, the use of rhAPC has been shown to be of benefit with a reduction in mortality and an improvement in indicators of inflammation and coagulation. OHSS is typically an iatrogenic disorder resulting from ovarian stimulation as a component of infertility treatment. The pathogenesis of OHSS, like sepsis, is related to endothelial dysfunction and inflammation and can result in significant morbidity including end organ hypoperfusion, disseminated intravascular coagulation (DIC), thrombosis, and occasionally, death. We have performed a review of the literature to identify similarities between these disease processes to develop a theoretical basis for the use of rhAPC in patients with moderate to severe OHSS. Use of rhAPC in this group may attenuate the disease process and reduce the potential morbidity associated with this iatrogenic disorder.

Use of metformin for prevention of ovarian hyperstimulation syndrome: a novel approach

In the present study, which includes 287 participants, metformin has been used by women undergoing IVF/intracytoplasmic sperm injection for more than 5 weeks before and during treatment and during luteal phase. There was no significant difference in number of gonadotrophins used, days of stimulation, number of oocytes retrieved, and number of embryos replaced. There was no significant difference in clinical pregnancy rate between both groups but there was significant reduction in the incidence of ovarian hyperstimulation syndrome (OHSS) in the group taking metformin. Metformin is a safe, cheap drug that can help in prevention of OHSS.

Value of the serum estradiol level for preventing ovarian hyperstimulation syndrome: a retrospective case control study

OBJECTIVE

To assess the value of different serum E(2) cut-off levels for predicting women at risk for ovarian hyperstimulation syndrome (OHSS).

DESIGN

Retrospective case-control study of a cohort of women undergoing assisted reproduction treatment (ART) over 12 months.

SETTING

Tertiary university hospital.

PATIENT(S)

The study group included women with OHSS who fulfilled the endocrine inclusion criteria (n = 40). The control group was a random sample (n = 40) from the cohort of women undergoing ART.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

To evaluate the sensitivity and specificity of different serum E(2) cut-off levels on day 11 of ovarian stimulation in preventing the establishment of OHSS.

RESULT(S)

Three hundred ninety-nine cycles (IVF and intracytoplasmic sperm injection) were undertaken between June 2000 and May 2001. The study group (n = 40) was compared with the control group (n = 40) undergoing ART during the same period of time. On day 8 of ovarian stimulation, the mean (SD) E(2) level in the study group was 8,517(5.3) pmol/L (2,320 pg/mL), and in the control group it was 2,540 (2.6) pmol/L (691 pg/mL). On day 11 of stimulation the mean (SD) E(2) level was 15,662 (4.2) pmol/L (4,266 pg/mL) and 5,804 (4.5) pmol/L (1,581 pg/mL), respectively. Twenty-four (60%) women who developed OHSS had E(2)levels >6,000 pmol/L (1,634 pg/mL) on day 8 and above 11,000 pmol/L (2,996 pg/mL) on day 11. Sixteen (40%) had E(2) levels <6,000 pmol/L (1,634 pg/mL) on day 8, but all had levels above 11,000 pmol/l (2,996 pg/mL) on day 11.

CONCLUSION(S)

A serum E(2) level of 12,315 pmol/L (3,354 pg/mL) on day 11 of ovarian stimulation gives a sensitivity and specificity of 85% for the detection of women at risk for OHSS.

Serum vascular endothelial growth factor levels are poorly predictive of subsequent ovarian hyperstimulation syndrome in highly responsive women undergoing assisted conception

OBJECTIVE

To determine whether serum vascular endothelial growth factor (VEGF) levels can distinguish highly responsive women who subsequently develop ovarian hyperstimulation syndrome (OHSS) from women with a similar ovarian response who do not.

DESIGN

Prospective controlled study.

SETTING

University IVF unit.

PATIENT(S)

Women undergoing IVF who met predetermined risk criteria for OHSS. Patients developing OHSS were compared with patients who did not develop OHSS.

INTERVENTION(S)

Long-protocol pituitary down-regulation followed by FSH stimulation by a standard protocol without coasting. A maximum of three embryos was transferred. Vaginal progesterone was used for luteal support.

MAIN OUTCOME MEASURE

Occurrence of OHSS; serum VEGF concentrations on the day of embryo transfer (ET) and at 5 and 10 days after ET.

RESULTS

Serum VEGF levels at any time point did not differ significantly between 9 OHSS cases and 9 controls. Vascular endothelial growth factor levels in samples collected from cases before the onset of OHSS were higher than levels in time-matched samples from controls (medians, 177.6 [range, 64.02-549.1] pg/mL vs. 100.7 [range, 37.59-246] pg/mL, respectively), but the difference failed to reach statistical significance (P=.0518), and there was considerable overlap between cases and controls.

CONCLUSIONS

Serum VEGF levels in the luteal phase do not distinguish between high-risk women who subsequently develop OHSS and women with a similar risk profile who do not develop OHSS.

Ovarian hyperstimulation syndrome is associated with reversible impairment of vascular reactivity

OBJECTIVE

To determine if there is a loss of normal peripheral arteriolar vasoconstrictor reactivity in women with severe ovarian hyperstimulation syndrome (OHSS).

SETTING

Prospective controlled study.

DESIGN

National University Hospital, Singapore.

PATIENT(S)

Forty-three women undergoing treatment in an IVF program: 22 women with severe OHSS and 21 normal women without OHSS.

INTERVENTION(S)

Measurement and quantification of the cutaneous arteriolar vasoconstrictor response using laser Doppler fluximetry.

MAIN OUTCOME MEASURE(S)

Changes in blood flow as an index of vasoconstrictor response before and after treatment for OHSS with albumin.

RESULT(S)

The mean (+/-SE) percentage (%) change in normal control women was -68.3% +/- 4.7. This was significantly different from women with OHSS (-32.3% +/- 11.1). The response in women with OHSS changed significantly after treatment with IV albumin (-60.4% +/- 5.7) and was no different than the control response. The reproducibility of the technique was -13.6% (+/-2.8).

CONCLUSION(S)

Women with OHSS have impaired vascular reactivity when compared with normal women.

Embryo freezing for preventing ovarian hyperstimulation syndrome: a Cochrane review

This paper is based on a Cochrane review published in The Cochrane Library, issue 3, 2002 (see www.CochraneLibrary.net for information) with permission from The Cochrane Collaboration and Update Software. Cochrane reviews are regularly updated as new evidence emerges and in response to comments and criticisms, and The Cochrane Library should be consulted for the most recent version of the review.

BACKGROUND

Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic condition resulting from an excessive ovarian response to superovulation medication. The objective of this review was to evaluate the effectiveness of cryopreservation (embryo freezing) when compared with human i.v. albumin infusion and with fresh embryo transfer for the prevention of OHSS.

METHODS

This was based on a Cochrane Review. Randomized controlled trials in which either human i.v. albumin or cryopreservation of all embryos was used as a therapeutic approach to OHSS were included. The participants were women down-regulated by GnRH agonist, undergoing superovulation in IVF/ICSI cycles. The interventions compared were cryopreservation versus i.v. human albumin administration and elective cryopreservation of all embryos versus fresh embryo transfer. The primary outcomes were: incidence of moderate and severe OHSS versus nil/mild OHSS, and clinical pregnancies/woman. Statistical analysis was performed in accordance with the Cochrane Menstrual Disorders and Subfertility Group guidelines.

RESULTS

Seventeen studies were identified, two of which met our inclusion criteria. One study was included where cryopreservation was compared with i.v. human albumin administration and another where elective cryopreservation of all embryos was compared with fresh embryo transfer. In both interventions no difference was found in all the outcomes examined between the two groups.

CONCLUSIONS

This review has shown that there is insufficient evidence to support routine cryopreservation and insufficient evidence for the relative merits of i.v. albumin versus cryopreservation.

Variations in serum vascular endothelial growth factor binding profiles and the development of ovarian hyperstimulation syndrome

OBJECTIVE

To compare the ability of serum to sequester vascular endothelial growth factor (VEGF) among patients who did and did not develop ovarian hyperstimulation syndrome (OHSS).

DESIGN

Prospective, observational study.

SETTING

A regional fertility centre with a commitment to research.

PATIENT(S)

Five patients undergoing controlled ovarian hyperstimulation as part of an in vitro fertilization cycle who developed severe OHSS, and five controls.

INTERVENTION(S)

Serum, collected at the time of oocyte retrieval, was incubated with radioactive VEGF (125I-VEGF(165)) for 2 hours before being passed down a sephadex G-150 gel filtration column. The fractional radioactive profile was then determined.

MAIN OUTCOME MEASURE(S)

The distribution of radioactive VEGF across the various fractions was measured in serum samples obtained from the two groups.

RESULT(S)

The 125I-VEGF(165) applied to the column eluted in two peaks centered on fractions 18 +/- 2 and 39 +/- 2. The molecular weight in the first peak was >300,000 kDa and represented "bound" VEGF; the second peak represented "unbound" VEGF. In the OHSS group, there was statistically significantly less radioactivity in the first peak than in the no-OHSS group.

CONCLUSION(S)

Patients who do not develop OHSS appear to have a high-molecular-weight protein that binds VEGF to a greater degree than occurs in patients who develop OHSS.

Human chorionic gonadotropin-induced ovarian hyperstimulation syndrome is associated with up-regulation of vascular endothelial growth factor

Ovarian hyperstimulation syndrome (OHSS), a life-threatening complication occurring in stimulated ovarian cycles, arises from treatment with gonadotropin for induction of follicular maturation in infertile women. Clinical characteristics of OHSS include ascites and pleural effusion induced by increased vascular permeability, where vascular endothelial growth factor (VEGF) was suspected to be the culprit. To test whether the effects of human CG (hCG) on the pathogenesis of OHSS were mediated through the VEGF produced by luteinized granulosa cells, we measured estradiol, VEGF, IGF-II levels in serum, and follicular fluid and analyzed their mRNA expression in luteinized granulosa cells obtained from 101 women (58 with OHSS and 43 controls) who underwent in vitro fertilization and embryo transfer. This study presents the first evidence that hCG up-regulated VEGF expression of granulosa cells in the OHSS, not the control groups, and that follicular VEGF worked through an autocrine mechanism using its kinase insert domain-containing receptor, not the fms-like tyrosine kinase receptor. We calculated total follicular production of VEGF, by multiplying follicular concentrations by follicular volumes, and verified that an increase in total follicular production of VEGF accounted for elevated serum levels of VEGF, which was associated with the development of OHSS. These findings demonstrate that through up-regulation of VEGF, hCG plays a significant role in the pathogenesis of OHSS.

Ovarian hyperstimulation syndrome and assisted reproductive technologies: why some and not others?

BACKGROUND

alpha(2)-Macroglobulin (alpha(2)M) is a multifactorial binding protein, found in follicular fluid, that is a naturally occurring inhibitor of vascular endothelial growth factor (VEGF). The aim of this study was to determine if there is a relationship between serum VEGF levels, alpha(2)M levels and the development of OHSS in hyperstimulated subjects undergoing IVF (those with 15 or more oocytes).

METHODS

Venous blood was collected at the time of oocyte retrieval from subjects who yielded 15 or more oocytes. Serum samples were analysed for VEGF and alpha(2)M concentrations.

RESULTS

There was no statistically significant difference in serum VEGF levels at the time of oocyte retrieval between hyperstimulated subjects who did and did not subsequently develop OHSS [3.95 (3.3-4.4) versus 3.85 (3.3-4.5); P = 0.79]. By contrast, the serum level of alpha(2)M was statistically significantly higher in the group of subjects who did not develop OHSS [2.27 (1.91-2.58) versus 1.67 (1.45-1.73)].

CONCLUSIONS

These results suggest that elevated alpha(2)M levels are associated with a decreased risk of developing OHSS. alpha(2)M may act by 'removing and inactivating' VEGF, with higher levels providing increased protection against the syndrome. alpha(2)M measurements may help to differentiate those for whom it is safe to proceed with embryo transfer from those for whom it is not, because of the risk of OHSS.

Aggressive outpatient treatment of ovarian hyperstimulation syndrome with ascites using transvaginal culdocentesis and intravenous albumin minimizes hospitalization

PURPOSE

To assess the effectiveness of outpatient treatment of Ovarian Hyperstimulation Syndrome associated with ascites.

METHODS

Forty-eight patients diagnosed with ovarian hyperstimulation and ascites from 2,246 consecutive in vitro fertilization cycles were retrospectively studied. Patients were treated with outpatient transvaginal culdocentesis and rehydration with intravenous crystalloids and albumin every 1-3 days until resolution of symptoms or hospitalization was required. Outcomes measured included incidences of hospitalization, pregnancy outcomes, cycle characteristics, and oocyte donors versus nondonors comparisons.

RESULTS

No complications occurred from outpatient treatments, and 91.6% of patients avoided hospitalization. The pregnancy rate in patients undergoing transfer was 84.7%, and the spontaneous loss rate was 16%. Overall, the estradiol on day of hCG was 4331 pg/mL (range 2,211-8,167), ascites removed was 1910 cm3 (122-4,000), and number of outpatient treatments was 3.4 (1-14). Nondonors averaged more outpatient treatments than donors (3.97 vs. 1.85), but similar rates of hospitalization (3/35 vs. 1/13).

CONCLUSIONS

Outpatient treatment consisting of culdocentesis, intravenous rehydration, and albumin minimized the need for hospitalization in hyperstimulated patients.

Vascular endothelial growth factor, interleukin-6 and interleukin-2 in serum and follicular fluid of patients with ovarian hyperstimulation syndrome

BACKGROUND

The pathogenesis of ovarian hyperstimulation syndrome (OHSS) is not completely understood.

OBJECTIVE

To investigate the presence of VEGF, IL-6 and IL-2, in serum and follicular fluid, in patients developing severe OHSS.

STUDY DESIGN

We enrolled 101 women undergoing in vitro fertilization. Eight patients developing severe OHSS were compared with 43 high risk patients and 50 controls. We analyzed VEGF and IL-6 in serum collected before hCG administration, and in both serum and follicular fluid on the day of oocyte retrieval.

RESULTS

OHSS patients presented follicular fluid IL-6 levels higher than both the patients at risk and controls (P<0.05). On the day of the oocyte retrieval the patients developing OHSS showed serum and follicular VEGF values higher than the ones of the patients at risk (P<0.05). Serum and follicular fluid IL-2 levels showed no differences between the examined groups. IL-2, IL-6 and VEGF values were not correlated with each other.

CONCLUSIONS

Angiogenesis and inflammation processes are both present in severe OHSS.

"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. Its reported incidence varies from 1% to 10% of in vitro fertilization (IVF) cycles. The factors leading to this syndrome have not been completely explained. It seems likely that the release of vasoactive substances, secreted by the ovaries under human chorionic gonadotropin (hCG) stimulation plays a key role in triggering this syndrome. The hallmark of this condition, is a massive shift of fluid from the intra-vascular compartment to the third space resulting in profound intra-vascular depletion and hemoconcentration.

OBJECTIVES

The objective of this review is to assess the effect of "coasting" (withholding gonadotrophins) as a preventative strategy in the management of OHSS following superovulation in assisted reproduction treatment on the incidence of all clinical grades of OHSS, in comparison with "early unilateral follicular aspiration (EUFA)" or other interventions.

SEARCH STRATEGY

Publications in the literature that described randomised controlled trials (RCTs) in which "coasting" was used as a preventative strategy to OHSS were included. The Cochrane Menstrual Disorders and Subfertility Review Group specialised register of controlled trials was searched. In addition, MEDLINE (PUBMED) 1985 to 2002, EMBASE (1985 to 2001), CINHAL (1985 to 2001) and National Research Register were also searched.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in which coasting was used as a preventative strategy to OHSS were included.

DATA COLLECTION AND ANALYSIS

Two reviewers, Mr N.N. Amso (NNA) and Dr A. D'Angelo (ADA) scanned the titles and the abstracts of the reports identified by electronic searching in order to find relevant papers. One reviewer (ADA) obtained copies of the full text articles and made copies for the other reviewer (NNA) in which details of authors, institution, results and discussion were removed in order to assess their eligibility for inclusion. Then, both reviewers extracted data independently using forms designed according to Cochrane guidelines. Disagreements were resolved by discussion. Additional information on the trial methodology or data were requested by writing twice to the corresponding authors directly. The interventions compared were "coasting" versus "early unilateral follicular aspiration (EUFA)" or no "coasting" or other interventions. Statistical analysis was performed in accordance with the Cochrane Menstrual Disorders and Subfertility Group guidelines.

MAIN RESULTS

This review identified thirteen studies but only one trial met our inclusion criteria. There was no difference in the incidence of moderate and severe OHSS (n=30, OR 0.76, 95% CI 0.18, 3.24)and in the clinical pregnancy rate (n=30, OR 0.75, 95% CI 0.17, 3.33) between the groups.

REVIEWER'S CONCLUSIONS

There is a lack of randomised controlled trials for where coasting is compared with no coasting or other interventions such as embryo freezing or intra-venous albumin infusion for prevention of OHSS. There is insufficient evidence to determine if coasting is an effective strategy for preventing OHSS.

Embryo freezing for preventing Ovarian Hyperstimulation Syndrome

BACKGROUND

Ovarian hyperstimulation syndrome (OHSS) is an iatrogenic potentially life threatening condition resulting from an excessive ovarian stimulation. Its reported incidence varies from 1% to 10% of in vitro fertilization (IVF) cycles. The factors leading to this syndrome have not been completely explained. It seems likely that the release of vasoactive substances, secreted by the ovaries under human chorionic gonadotropin (hCG) stimulation plays a key role in triggering this syndrome. The hallmark of this condition, is a massive shift of fluid from the intra-vascular compartment to the third space resulting in profound intra-vascular depletion and hemoconcentration.

OBJECTIVES

To evaluate (i) the effectiveness of cryopreservation (embryo freezing) for the prevention of OHSS when compared with human intra-venous albumin infusion and (ii) the effectiveness of the elective cryopreservation (embryo freezing ) of all embryos for the prevention of OHSS when compared with fresh embryo transfer.

SEARCH STRATEGY

Publications in the literature that describe or may describe randomised controlled trials of both human intra-venous albumin and freezing of all embryos in the management of OHSS as consequence of the superovulation in assisted reproduction techniques (ART) cycles were searched. The Cochrane Menstrual Disorders and Subfertility Review Group specialised register of controlled trials was searched. In addition, MEDLINE (PUBMED 1985 to 2001), EMBASE (1985 to 2001), CINHAL (1985 to 2001) and the National Research Register were searched

SELECTION CRITERIA

Randomised controlled trials (RCTs) in which either human intra-venous albumin or cryopreservation of all embryos were used as a therapeutic approach to OHSS were included. The participants were women of reproductive age who were down regulated by gonadotrophin-releasing hormone-analogue (GnRH-a), undergoing superovulation in in vitro fertilization/intra-cytoplasmic sperm injection (IVF/ICSI) cycles.

DATA COLLECTION AND ANALYSIS

Two reviewers, Mr N.N. Amso (NNA) and Dr A. D'Angelo (ADA) scanned the titles and the abstracts of the reports identified by electronic searching in order to find relevant papers. One reviewer (ADA) obtained copies of the full text articles and made copies for the other reviewer (NNA) in which details of authors, institution, results and discussion were removed in order to assess their eligibility for inclusion. Then, both reviewers extracted data independently using forms designed according to Cochrane guidelines. Disagreements were resolved by discussion. Additional information on the trial methodology or data were requested by writing to the corresponding authors directly. The interventions compared were cryopreservation (embryo freezing) versus intra-venous human albumin administration and elective cryopreservation of all embryos versus fresh embryo transfer. The primary outcomes were: incidence of moderate and severe OHSS versus nil/mild OHSS, clinical pregnancies/woman. The secondary outcomes were: number of oocytes retrieved, number of oocytes fertilized, number of embryos transferred, number of embryos frozen, multiple pregnancy rate, live birth rate, number of women admitted to the hospital as inpatient or outpatient and time to the next menstrual period (resolution time). Statistical analysis was performed in accordance with the Cochrane Menstrual Disorders and Subfertility Group guidelines.

MAIN RESULTS

Seventeen studies were identified, two of which met our inclusion criteria. One study was included where cryopreservation (embryo freezing) was compared with intra-venous human albumin administration (Shaker 1996) and one study was included where elective cryopreservation of all embryos was compared with fresh embryo transfer (Ferraretti 1999). When cryopreservation was compared with intra-venous human albumin administration no difference was found in all the outcomes examined between the two groups. When elective cryopreservation of all embryos was compared with fresh embryo transfer no difference was found in all the outcomes examined between the two groups.

REVIEWER'S CONCLUSIONS

This review has showed that there is insufficient evidence to support routine cryopreservation and insufficient evidence for the relative merits of intra-venous albumin versus cryopreservation.

A rise of the serum level of von Willebrand factor occurs before clinical manifestation of the severe form of ovarian hyperstimulation syndrome

BACKGROUND

Ovarian hyperstimulation syndrome (OHSS) appears to be caused by increased capillary permeability in the vascular endothelial cells. Such cells secrete excess amounts of von Willebrand factor (vWF), a large adhesive glycoprotein.

METHODS

We retrospectively evaluated the circulating levels of vWF and of vascular endothelial growth factor (VEGF) twice, on the days of oocyte retrieval and embryo transfer, in 46 women who developed early-onset OHSS.

RESULTS

Nineteen, 14, and 13 women developed mild, moderate, and severe OHSS, respectively. Inconsistent changes were observed in the VEGF during oocyte retrieval and embryo transfer. However, the net increase in serum vWF during that period showed an increase in absolute value at the time of embryo transfer that paralleled an increase in the severity of OHSS. That is, in mild OHSS, the serum vWF increased from 140 +/- 44 to 164 +/- 28%; in moderate OHSS, it increased from 113 +/- 47 to 186 +/- 22%; and in severe OHSS, it increased from 120 +/- 35 to 274 +/- 63%. All 9 women with a vWF level > 230% at embryo transfer developed severe OHSS, while 9 of 13 women with severe OHSS exhibited a vWF > 230% at embryo transfer.

CONCLUSION

The results suggest that a rise of the serum level of vWF occurs prior to clinical manifestation of OHSS in patients with severe OHSS but not in patients with mild OHSS.

Dynamics of immunoreactive endothelin plasma levels during ovarian stimulation for in vitro fertilization with and without dietary sodium restriction

OBJECTIVE

To investigate the correlation between immunoreactive endothelin plasma levels and both the number and size of follicles and its relationship with the development of ovarian hyperstimulation syndrome, in in vitro fertilization cycles, with and without dietary sodium restriction.

STUDY DESIGN

Randomized study in an assisted reproduction unit of a large teaching hospital. Data of 88 women form the basis of this report (45 ad libitum sodium intake and 43 dietary sodium restriction). Non-parametric tests were used for statistical analysis.

RESULTS

Immunoreactive endothelin plasma levels neither correlate with the number of follicles, independent of their size, nor with the grade of ovarian hyperstimulation syndrome. Immunoreactive endothelin plasma levels decrease significantly in the luteal phase. These results are the same in both sodium diet groups.

CONCLUSIONS

Immunoreactive endothelin plasma levels do not correlate with the number and size of follicles and they are not related to the development of ovarian hyperstimulation syndrome. These findings are independent of sodium intake.

The ovarian hyperstimulation syndrome

OBJECTIVE

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

DESIGN

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

PATIENT(S)

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

INTERVENTION(S)

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

MAIN OUTCOME MEASURE(S)

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

RESULT(S)

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

CONCLUSION(S)

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

Ovarian hyperstimulation syndrome

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

Prognostic importance of serial cytokine changes in ascites and pleural effusion in women with severe ovarian hyperstimulation syndrome

OBJECTIVE

To determine the prognostic value of various cytokine levels in ascites and pleural effusion during the evolution of severe ovarian hyperstimulation syndrome (OHSS).

DESIGN

A longitudinal study.

SETTING

University teaching hospital.

PATIENT(S)

Twenty patients with severe OHSS who required either paracentesis or thoracentesis or both from whom ascites (n = 56) or pleural effusion (n = 12) samples were obtained. Control peritoneal fluid was obtained from 20 patients undergoing ovarian stimulation for IVF.

INTERVENTION(S)

Abdominal paracentesis for tense ascites and thoracentesis for massive pleural effusion. Control peritoneal fluid was obtained before oocyte retrieval.

MAIN OUTCOME MEASURE(S)

Levels of interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-alpha (TNF-alpha), vascular endothelial growth factor (VEGF), E2, and progesterone concentrations in ascites and pleural effusion.

RESULT(S)

Levels of VEGF and IL-6 in ascites dropped significantly during the course of OHSS and were not correlated with E2 concentrations. Levels of VEGF were significantly correlated with levels of IL-1 beta, IL-8, and TNF-alpha, as well as progesterone concentrations, hematocrit, and white blood cell counts. None of the cytokine levels measured in pleural effusion were correlated with the course of OHSS.

CONCLUSION(S)

These results suggest that local cytokines might be involved in the evolution of severe OHSS and possibly serve as prognostic markers for this syndrome.

Clinical aspects of ovarian hyperstimulation syndrome

Ovarian hyperstimulation syndrome (OHSS) is characterized by massive transudation of protein-rich fluid (mainly albumin) from the vascular space into the peritoneal pleural and to a lesser extent to the pericardial cavities. The intensity of the syndrome is related to the degree of the follicular response in the ovaries to the ovulation inducing agents. OHSS is still a threat to every patient undergoing ovulation induction. The pathophysiology of OHSS is of extreme importance in the face of the increased use of ovulation induction agents as well as the development of sophisticated assisted reproductive techniques. The correlation found between plasma cytokine activities and the severity of OHSS suggests that plasma cytokines may be involved in the pathogenesis of OHSS and may serve as a means of monitoring the syndrome during the acute phase and throughout convalescence. The interactions between cytokine and non-cytokine mediators of the syndrome, such as the renin-angiotensin system and vascular endothelial growth factor were recently clarified. Awareness of possible mechanisms and factors in the pathophysiology of OHSS will hopefully provide opportunities to design specific treatment regimens effective for both prevention and treatment of this potentially fatal iatrogenic condition. Among IVF patients with severe and critical OHSS, pregnancy rates, multiple gestations, miscarriage, preterm premature rupture of the membranes, prematurity, and low birth weight rates are significantly higher than those reported previously for pregnancies after assisted conception. The incidence of other obstetrical complications, as well as congenital malformations and Cesarean section rates are not significantly different.

The pathogenesis of ovarian hyperstimulation syndrome: in vivo studies investigating the role of interleukin-1beta, interleukin-6, and vascular endothelial growth factor

OBJECTIVE

To evaluate systemic and ovarian changes in levels of interleukin (IL)-1beta, IL-6, and vascular endothelial growth factor (VEGF) in response to hCG administration to determine which may be the potential initiator of vascular effects and to identify the main source of the substance; to evaluate serum and follicular fluid levels of these cytokines as markers of ovarian hyperstimulation syndrome (OHSS), and to compare levels of these cytokines under basal conditions in women with normal ovulation and those with polycystic ovary syndrome (PCOS).

DESIGN

Prospective controlled study.

SETTING

In vitro fertilization program at the Instituto Valenciano de Infertilidad, Valencia, Spain.

PATIENT(S)

Women undergoing IVF, in whom the first two study objectives were analyzed, and women with normal ovulation and patients with PCOS undergoing retrieval of immature oocytes in natural cycles or cycles stimulated for IUI but cancelled during induction of ovulation, in whom the third study objective was analyzed.

INTERVENTION(S)

Serum was collected before and after hCG administration, and follicular fluid was collected at ovum pick-up.

MAIN OUTCOME MEASURE(S)

Serum and follicular fluid levels of IL-1beta, IL-6, and VEGF.

RESULT(S)

There was a significant increase in serum VEGF levels after hCG administration in patients who were at risk for OHSS compared with those who were not at risk for OHSS. Significantly lower VEGF levels were found in the follicular fluid of patients who were at risk; this decrease was the only useful marker to discriminate between the two groups. Moreover, both groups had similar cytokine production under basal conditions. An increase in serum E2 occurred coincident with a decrease in IL-1beta, IL-6, and VEGF in patients with PCOS.

CONCLUSION(S)

Vascular endothelial growth factor seems to be the mediator of hCG on the vascular tree. There was an early systemic increase in VEGF that may have significance in the development of OHSS. A decrease in the follicular fluid VEGF concentration is a valid marker to identify women in whom OHSS will develop. The pattern of cytokine release in patients with PCOS under basal conditions was not different from that in women with normal ovulation.

Role of vascular endothelial cell growth factor in Ovarian Hyperstimulation Syndrome

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

Ovarian hyperstimulation syndrome: facts and fallacies

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

Transvaginal drainage of ascites as an alternative to abdominal paracentesis in patients with severe ovarian hyperstimulation syndrome, obesity, and generalized edema

OBJECTIVE

To describe an alternative technique for transvaginal drainage of ascites in a case of severe ovarian hyperstimulation syndrome (OHSS), generalized edema, and obesity.

DESIGN

Case report.

SETTING

A university-based hospital IVF and Reproductive Medicine Unit.

PATIENT(S)

A patient hospitalized with severe OHSS after IVF-ET in whom drainage of large amounts of ascitic fluid was necessary.

INTERVENTION(S)

Ultrasonographic transvaginal insertion of a wire guide through a standard IVF needle into the Douglas pouch. Placement of a "peel-away" set on the wire, which was replaced with a "pigtail" indwelling catheter.

MAIN OUTCOME MEASURE(S)

Amount of drained ascitic fluid.

RESULT(S)

Ascitic fluid was drained efficiently, leading to improvement of the patient's condition.

CONCLUSION(S)

Transvaginal ultrasonography-guided insertion of a pigtail catheter through the Douglas pouch is an efficacious procedure when the abdominal approach for decompression of ascites is difficult.

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

OBJECTIVE

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

DESIGN

Retrospective analysis of clinical laboratory data.

SETTING

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

PATIENT(S)

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

INTERVENTION(S)

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

MAIN OUTCOME MEASURE(S)

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

RESULT(S)

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

CONCLUSION(S)

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

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

A unilateral hydrothorax as the only manifestation of ovarian hyperstimulation syndrome: a case report

OBJECTIVE

To describe a rare case of unilateral hydrothorax occurrence after ovarian stimulation for IVF.

DESIGN

Case report.

SETTING

A university hospital.

PATIENT(S)

A 39-year-old female suffering from primary infertility due to a severe male factor.

INTERVENTION(S)

Thoracocentesis with IV albumin administration for correction of a concomitant hypoalbuminemia.

MAIN OUTCOME MEASURE(S)

Laboratory values of hematologic measures and electrolytes, screening of the thoracic fluid aspirated for viral and bacterial infections, resolution of pleural effusion after the second thoracocentesis as determined by chest roentgenogram.

RESULT(S)

Treatment of this manifestation of the ovarian hyperstimulation syndrome (OHSS) by thoracocentesis with albumin perfusion.

CONCLUSION(S)

This report describes a very rare case of thoracic complication after ovarian stimulation. It demonstrates that pleural effusion may be the only manifestation of the OHSS and implies a careful management of patients with pulmonary complaints after treatment with exogenous gonadotropins.

Intrafollicular hemodynamics before the administration of human chorionic gonadotropin in women at risk of the ovarian hyperstimulation syndrome

OBJECTIVE

To test the hypothesis that alteration of intrafollicular hemodynamics precedes the ovarian hyperstimulation syndrome (OHSS).

DESIGN

A prospective study.

SETTING

The IVF unit and the Doppler imaging laboratory of King's College Hospital, London.

PATIENTS

Twenty-four women undergoing IVF and considered to have an exaggerated response to ovarian stimulation and hence at risk of OHSS.

INTERVENTIONS

Transvaginal Doppler imaging of the intrafollicular blood flow was performed before hCG administration to determine the indexes of intrafollicular hemodynamics.

MAIN OUTCOME MEASURES

Moderate or severe OHSS.

RESULTS

There was no statistically significant difference in mean age (32.63 +/- 1.77 versus 31.48 +/- 3.87), duration of infertility (6.00 +/- 2.19 versus 5.29 +/- 2.73), maximum peak systolic velocity (0.25 +/- 0.16 versus 0.26 +/- 0.21 m/s), mean of six maximal peak systolic velocity (0.15 +/- 0.04 versus 0.21 +/- 0.10), minimum pulsatility index (0.76 +/- 0.26 versus 0.59 +/- 0.23), mean of six minimal pulsatility indexes (0.89 +/- 0.30 versus 0.79 +/- 0.14), minimum resistance index (0.47 +/- 0.06 versus 0.41 +/- 0.10), and mean of six minimal resistance indexes (0.56 +/- 0.05 versus 0.53 +/- 0.06) of intrafollicular blood flow between the women who developed moderate or severe OHSS and matched controls.

CONCLUSION

Measurement of intrafollicular hemodynamics before hCG administration does not predict the development of the OHSS.