Withholding gonadotropins ("coasting") to minimize the risk of ovarian hyperstimulation during superovulation and in vitro fertilization-embryo transfer cycles

Luteinizing hormone changes in gonadotropin-releasing hormone antagonist protocol in in vitro fertilization cycles: A cross-sectional study

Background

Because of the unexpected and often dramatic inhibition of luteinizing hormone (LH) secretion related with the usage of gonadotropin-releasing hormone (GnRH)-antagonist, there has been a probable need for exogenous LH supplementation. There is a basic and clinical evidences that show late development of follicle needs an LH but there is a threshold for LH requirements during folliculogenesis.

Objective

The purpose of this study was to evaluate the changes in serum LH and the identification of patients who benefit from the addition of LH.

Materials and Methods

Seventy volunteers for antagonist protocol in IVF cycle were enrolled in this prospective cross-sectional study. The study was carried out in Reproductive Health Research Center, University of Medical Sciences between July 2016 and February 2016. Serum LH level was estimated 24 h before and after the first (GnRH) antagonist injection. The primary outcome was the serum level of LH and its change in the three groups and the secondary outcome was Egg and Embryo quality.

Results

LH changes above or below 50% had no effect on the number of follicle, the number of oocyte, Germinal vesicle oocyte, metaphase 1 oocyte, metaphase 2 oocyte, endometrial thickness, and chemical and clinical pregnancy.

Conclusion

We evaluated the changes of serum LH in the patients who were entered in the antagonist protocol. Our study showed no significant difference in LH levels 24 h before and after the injection of the antagonist between the three groups, and LH changes did not affect the outcome of pregnancy.

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.

Is Coasting Valuable in All Patients with Any Cause of Infertility?

OBJECTIVES

This study aimed to assess the influence of coasting duration on the number and quality of oocytes and fertilization rate in male factor infertile women and those with polycystic ovary syndrome (PCOS).

METHODS

In this prospective observational follow-up study, 114 patients undergoing coasting (53 women with male factor infertility and 61 women with PCOS) were evaluated at the Royan Institute Research Center, Iran, between 2010 and 2012.

RESULTS

The results were analyzed according to the coasting periods of 1-4 days. In normal females, the number of oocytes retrieved was significantly reduced after the second day (p = 0.004). In addition, a statistically significant drop was observed in the number of metaphase II oocytes and fertilization rate after the third day (p = 0.006 and p = 0.006, respectively). No significant differences were observed in the number and quality of oocytes retrieved and fertilization rate with regard to coasting days in PCOS patients.

CONCLUSION

Coasting with duration of more than three days should be performed with caution in normal females who are at risk of developing ovarian hyperstimulation syndrome.

GnRH antagonist rescue protocol combined with cabergoline versus cabergoline alone in the prevention of ovarian hyperstimulation syndrome: a randomized controlled trial

Background

The aim of this study was to compare the efficacy of antagonist rescue protocol (replacing GnRH agonist with GnRH antagonist and reducing the dose of gonadotropins) combined with cabergoline versus cabergoline alone in the prevention of ovarian hyperstimulation syndrome (OHSS) in patients pretreated with GnRH agonist long protocol who were at high risk for OHSS.

Methods

Two hundred and thirty six patients were randomized in a 1:1 ratio to the cabergoline group or the antagonist rescue combined with cabergoline group. Both groups received oral cabergoline (0.5 mg/day) for eight days beginning on the day of HCG administration. In the antagonist rescue combined with cabergoline group, when the leading follicle reached 16 mm, GnRH agonist (triptorelin) was replaced with GnRH antagonist (cetrorelix acetate) and the dose of HP-uFSH was reduced to 75 IU/day. HCG (5,000 IU/I.M) was administered when the serum estradiol level dropped below 3500 pg/ml. The study was open label and the outcome assessors (laboratory staff and the doctor who performed oocyte retrieval) were blind to treatment allocation.

Results

The incidence of moderate/severe OHSS was significantly lower in the antagonist rescue combined with cabergoline group [5.08 % Vs 13.56 %, P value =0.025, OR = 0.342, 95 % CI, 0.129–0.906]. Four cycles were cancelled in the cabergoline group. There were no significant differences between the groups with respect to the number of retrieved oocytes, metaphase II oocytes, high quality embryos and fertilization rate. Moreover, the implantation and pregnancy rates were comparable between both groups.

Conclusion

GnRH antagonist rescue protocol combined with cabergoline is more effective than cabergoline alone in the prevention of OHSS.

Trial registration

Clinical trial.gov (NCT02461875).

The continuum of high ovarian response: a rational approach to the management of high responder patient subgroups

Ovarian follicular responsiveness to controlled ovarian hyperstimulation (COH) with gonadotropins is extremely variable between individual patients, and even from cycle to cycle for the same patient. High responder patients are characterized by an exaggerated response to gonadotropin administration, accompanied by a higher risk for ovarian hyperstimulation syndrome (OHSS). In spite of its importance, the literature regarding high responders is characterized by heterogeneous classification methodologies. A clear separation should be drawn between risk factors for a high ovarian response and the actual response exhibited by a patient to stimulation. Similarly, it is important to distinguish between high ovarian response and development of clinically significant OHSS. In this article we: (1) review recent publications pertaining to the identification and clinical management of high responders, (2) propose an integrated clinical model to differentiate sub-groups within this population based on this review, and (3) suggest specific protocols for each sub-group. The model is based on a chronological patient assessment in an effort to target treatment based on the specific clinical circumstances. It is our hope that the algorithm we have developed will assist clinicians to supply targeted and precise treatments in order to achieve a favorable reproductive outcome with minimum complications for each patient.

Microdose flare protocol with interrupted follicle stimulating hormone and added androgen for poor responders--an observational pilot study

OBJECTIVE

To investigate whether temporarily withholding FSH and adding androgen could improve follicular response during a microdose flare protocol in women with slow follicular growth or asynchronous follicular development.

DESIGN

Observational pilot study.

SETTING

University-affiliated private fertility center.

PATIENT(S)

Twenty-six women aged 34-47 years with poor response to stimulation or a previous cancelled IVF cycle and with slow or asynchronous follicular growth during a microdose flare cycle.

INTERVENTION(S)

For 13 women, after initiation of ovarian stimulation using the microdose flare protocol, gonadotropin administration was interrupted and transdermal testosterone gel was added for several days (4.4 ± 1.2 d) starting after cycle day 7 (mean cycle day 10 ± 2.6).

MAIN OUTCOME MEASURE(S)

FSH, E2, follicular growth, and total number of mature oocytes retrieved were determined for all of the patients. Cycle cancellation rate as well as pregnancy rate following embryo transfer were also documented when applicable.

RESULT(S)

FSH levels declined (25.2 ± 6.5 to 6.8 ± 3.2 IU/L), E2 levels increased (896 ± 687 to 2,163 ± 1,667 pmol/L), and follicular growth improved significantly during gonadotropin interruption and were tracked for 2 days during this time frame. The average number of oocytes retrieved was 5.3 ± 2.6, and the ratio of mature to total oocytes was 4:5. Four of the 13 women in the interruption group conceived following frozen embryo transfer, whereas none in the control group did.

CONCLUSION(S)

The androgen-interrupted FSH protocol may improve follicular response to gonadotropins in cycles that might otherwise be cancelled.

Serum FSH Levels in Coasting Programmes on the hCG Day and Their Clinical Outcomes in IVF ± ICSI Cycles

Introduction. Coasting is the most commonly used strategy in prevention of severe OHSS. Serum FSH levels measurements during coasting may aid in optimizing the duration of coasting. Objective(s). To study live birth rates (LBRs), clinical pregnancy rates (CPRs), and optimal duration of coasting based on serum FSH levels on the hCG day. Materials and Methods. It is a retrospective study performed between 2005 and 2008 at Barts and The London Centre for Reproductive Medicine, NHS Trust, London, UK, on 349-coasted women undergoing controlled ovarian stimulation (COS) for IVF ± ICSI. The serum FSH level measurements on the hCG day during coasting programme were analysed to predict the LBR and CPR. Result(s). LBR and CPR were significantly higher when the FSH levels on the hCG day were >2.5 IU/L (LBR: 32.5%, P = 0.045 and CPR: 36.9%, P = 0.027) compared to FSH <2.5 IU/L. The optimal FSH cut-off level for LBR and CPR is 5.6 IU/L on the hCG day. The optimal cutoff for coasting is 4 days. Conclusion(s). Coasting may be continued as long as either serum FSH level is > 2.5 IU/L on the hCG day without compromising the LBR and CPR or to maximum of 4 days.

[Ovarian hyperstimulation syndrome: pathophysiology, risk factors, prevention, diagnosis and treatment]

The ovarian hyperstimulation syndrome is a major complication of ovulation induction for in vitro fertilization, with severe morbidity and possible mortality. Whereas its pathophysiology remains ill-established, the VEGF may play a key role as well as coagulation disturbances. Risk factors for severe OHSS may be related to patients characteristics or to the management of the ovarian stimulation. Two types of OHSS are usually distinguished: the early OHSS, immediately following the ovulation triggering and a later and more severe one, occurring in case of pregnancy. As no etiologic treatment is available, the therapeutic management of OHSS should focus on its related-complications. Thrombotic complications that can occur in venous or arterial vessels represent the major risk of OHSS, possibly conducting to myocardial infarction and cerebrovascular accidents. Once the OHSS is diagnosed, prevention of thrombotic accidents remains the major issue.

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.

IVF outcome in women with PCOS, PCO and normal ovarian morphology

OBJECTIVE

To examine the outcome of IVF in women who have normal ovaries, ovulatory PCO or PCOS.

STUDY DESIGN

Analysis of a prospectively collected database in an assisted conception unit in a university teaching hospital including 290 women <37 years of age undergoing their first IVF cycle. The main outcome measure was severe OHSS requiring hospitalization.

RESULTS

Severe OHSS rates were significantly higher in women with PCO (12.6%) and PCOS (15.4%) compared to those with normal ovaries (2.7%). Coasting was used significantly more often. Live birth rates per cycle started are similar among women with PCO (38%), PCOS (37%) and normal ovaries (40%).

CONCLUSION

Women with ovaries of polycystic morphology are at increased risk of developing severe OHSS and of requiring avoidance techniques such as coasting, regardless of ovulatory status. However, live birth rates per cycle are similar to women with normal ovaries.

Effect of coasting on IVF cycle characteristics and outcome in short vs. long GnRH agonist protocols

AIMS

To compare the results of IVF cycles following coasting in patients treated with long versus short GnRH agonist protocols.

METHODS

A retrospective comparative study in which all women aged 35 years or less attending the IVF unit from 2000 to 2006 in whom coasting was used in GnRH agonist protocols were included. Data on coasting-related variables and outcome were collected from the files and compared between the short GnRH agonist (n = 78) and long GnRH agonist (n = 181) cycles.

RESULTS

The short GnRH agonist cycles were characterized by higher E2 levels during coasting and longer duration of coasting than the long GnRH agonist cycles. Although the number of retrieved oocytes was lower following coasting in the short protocol, there was no difference between the groups in fertilization rate, number of high-quality embryos available for transfer, and pregnancy rate. Pregnancy rate in both protocols was negatively correlated to E2 level at initiation of coasting. The overall moderate and severe OHSS rate after coasting was 5.1% in the short-protocol group and 6.0% in the long-protocol group (p = 0.76).

CONCLUSIONS

The ovarian response curve to coasting is longer in the short than in the long GnRH-agonist protocol, but there is no significant difference in pregnancy or OHSS rates.

Short coasting of 1 or 2 days by withholding both gonadotropins and gonadotropin-releasing hormone agonist prevents ovarian hyperstimulation syndrome without compromising the outcome

OBJECTIVE

To evaluate the effect of short coasting, by withdrawing both gonadotropins and gonadotropin-releasing hormone (GnRH) agonist, on the prevention of severe ovarian hyperstimulation syndrome (OHSS) without compromising pregnancy outcome.

DESIGN

Retrospective study.

SETTING

Large urban medical center.

PATIENT(S)

Forty-four women who had been coasted during controlled ovarian hyperstimulation (COH) for in vitro fertilization (IVF).

INTERVENTION(S)

When >or=20 follicles >15 mm with serum estradiol (E(2)) level of 4000 pg/mL were detected, both gonadotropins and GnRH agonist were withheld for 1 to 2 days.

MAIN OUTCOME MEASURE(S)

Changes of serum E(2) levels, number of oocytes retrieved, pregnancy rate.

RESULT(S)

The mean serum E(2) level fell from 7915 pg/mL at the onset of coasting to 3908 pg/mL on the day of human chorionic gonadotropin (hCG) administration. The mean number of oocytes retrieved and fertilization rate were 17.2% and 75.0%, respectively. Eighteen patients became pregnant (43.9%), and the implantation rate was 12.7%. Twenty-eight patients were coasted for 1 day, and 13 were coasted for 2 days. The mean decrease rate of serum E(2) level was 45.3% in 1-day coasting and 26.4% (first day) and 75.3% (second day) in 2-day coasting. The pregnancy outcome was similar between both groups. After coasting, three mild and two severe cases of OHSS occurred.

CONCLUSION(S)

Coasting for 1 or 2 days can be used successfully to prevent OHSS without compromising IVF cycle outcome.

The optimal length of 'coasting protocol' in women at risk of ovarian hyperstimulation syndrome undergoing in vitro fertilization

Ovarian hyperstimulation syndrome (OHSS) is a serious and potentially life-threatening complication following ovarian stimulation for in vitro fertilization (IVF). Coasting is the practice whereby the gonadotrophins are withheld and the administration of human chorionic gonadotrophin (hCG) is delayed until serum oestradiol (E2) has decreased to what is considered to be a safe level, to prevent the onset of OHSS. This study aimed to assess the length of coasting on the reproductive outcome in women at risk of developing OHSS. Coasting was undertaken when the serum E2 concentrations were > or = 17000 pmol/L but < 21000 pmol/L. Daily E2 measurements were performed and hCG was administered when hormone levels decreased to < 17000 pmol/L. Eighty-one women who had their stimulation cycles coasted were grouped according to the number of coasting days. Severe OHSS occurred in one case, which represented 1.2% of patients who underwent coasting because of an increased risk of developing the syndrome. No difference was found between cycles coasted for 1 - 3 days and cycles coasted for > or = 4 days in terms of oocyte maturity, fertilization and embryo cleavage rates. Women in whom coasting lasted for > or = 4 days had significantly fewer oocytes retrieved (P < 0.05) and decreased implantation rate (P < 0.05) compared to those coasted for 1 - 3 days. Pregnancy rate/embryo transfer and live birth rate did not differ between groups. In conclusion, coasting appears to decrease the risk of OHSS without compromising the IVF cycle pregnancy outcome. Prolonged coasting is, however, associated with reduced implantation rates, perhaps due to the deleterious effects on the endometrium rather than the oocytes.

Effect of a sharp serum oestradiol fall before HCG administration during ovarian stimulation in donors

The current study evaluated how a sudden fall in serum oestradiol during ovarian stimulation in donors affects recipient outcome. After the assessment of pregnancy rate in cases of oestradiol falls of <10 or > or =10% (57.0 versus 45.6%), <20 or > or = 20% (55.2 versus 44.9%), <25 or > or =25% (57.2 versus 41.2%), and < 30 or > or =30% (57.1 versus 32.0%; P < 0.05), a significantly lower pregnancy rate was observed when the fall was > or =30%. Therefore, the study group (n = 25) included recipients who received oocytes from donors with a fall of > or =30%, and the control group included patients (n = 197) in which the fall in oestradiol was <30% and all cases with no fall in oestradiol concentrations. Pregnancy rates in both groups were 32.0 versus 57.1%; P < 0.05. The number of morphologically normal oocytes was similar (14.2 versus 18.1%) and good quality embryos was lower (8.0 versus 21.0%; P < 0.05) for study group. This seems related to a lower capability of the embryos to implant (15.2 versus 37.4%; P < 0.001). These data indicate that a fall of > or =30% in serum oestradiol concentration during ovarian stimulation in donors negatively affects pregnancy rates and embryo quality in recipients. In these cases, cycle cancellation should be considered.

Safety of drugs used in assisted reproduction techniques

Infertility may affect one in six couples; however, the development of the assisted reproduction technique (ART) created the opportunity for a large proportion of the infertile population to bear children. Pharmacological agents are routinely used in ART, and new ones are introduced regularly, with the aim of retrieving multiple oocytes to increase the prospect of pregnancy. The combinations of drugs that are used have specific adverse effects, but it is mostly the combined action of more than one agent that causes the greatest concern. The matter is complicated by the suspicion that some techniques in ART, for example intracytoplasmic sperm injection for severe male infertility problems (including azoospermia), may also contribute to the increase in adverse effects, especially congenital malformation. Gonadotropin releasing hormone (GnRH) agonists are widely used in controlled ovarian hyperstimulation. It may give rise to a short period of estradiol withdrawal symptoms and it may also lead to luteal phase deficiency. Similarly GnRHa antagonists, which have been recently introduced to control ovarian hyperstimulation, can lead to luteal phase deficiency and may cause some local injection site reactions. The more pure form of gonadotropin leads to less local injection site reactions and their main adverse effects are associated with the consequences of multiple ovulations. It has been proposed that gonadotropins may be a factor in the increasing risk of ovarian cancer and possibly breast cancer, but this has not been substantiated. Prion infection is another potential hazard, although no cases have been reported. Ovarian hyperstimulation syndrome is a well recognised complication of controlled ovarian hyperstimulation in ART. It is usually a result of recruitment of a large number of ovarian follicles. Efforts to minimise the incidence of this syndrome and its severity are now well developed. Congenital malformations are another possible adverse effect of fertility drugs, but it is more probable that the increase in congenital abnormality that is reported in ART is because of the population studied, i.e. patients already at high risk of congenital malformation, rather than the fertility drugs used or the technique employed. High order multiple pregnancy and its sequela is a well established complication of controlled ovarian hyperstimulation. This could be a result of multiple ovulations or more than one embryo replacement. Reducing the number of embryos transferred can reduce this more serious adverse effect for expectant mothers and for children conceived from ART.

Coasting for the prevention of ovarian hyperstimulation syndrome: much ado about nothing?

OBJECTIVE

To review and critique the literature and our own experience regarding coasting as a strategy to prevent ovarian hyperstimulation syndrome (OHSS).

DESIGN

Identification of relevant clinical literature through PubMed and EMBASE databases, as well as the experience of our institution with this approach.

CONCLUSION(S)

Coasting is a rescue procedure that can be avoided by carefully adjusting the gonadotropin dosage. It is a good alternative that can be used to avoid cycle cancellation in extremely high responders to controlled ovarian hyperstimulation, who have a high risk of developing severe OHSS. Even if OHSS develops after coasting, both its incidence and severity will be diminished. Each case should be individually counseled to determine whether the patient should be coasted, and her hypothetical risks and benefits should be evaluated. Until the multifactorial etiopathogenesis of OHSS is completely understood, absolute prevention will not be possible, but coasting is definitely of great benefit.

Effect of coasting on the implantation potential of embryos transferred after cryopreservation and thawing

OBJECTIVE

To examine the effect of withholding gonadotropins on the outcome of embryos after cryopreservation and thawing.

DESIGN

Retrospective clinical evaluation of patients having cryopreserved-thawed ET trials with coasting during the corresponding ovarian stimulation cycle.

SETTING

Academic tertiary clinical care unit.

PATIENT(S)

Patients with cryopreserved embryos having coasting in their fresh IVF cycle and age-matched controls without coasting, both groups receiving the same stimulation protocol (long GnRH agonist plus recombinant FSH).

INTERVENTION(S)

All patients had a cycle in which embryos were transferred fresh and a cycle of thawing of cryopreserved embryos with the aim of transferring in a steroid-supplemented cycle.

MAIN OUTCOME MEASURE(S)

Embryo survival, implantation, and clinical pregnancy rates.

RESULT(S)

Post-thawing embryo survival (66.4% vs. 73%), implantation (12.3% vs. 13.0%), and clinical pregnancy rates (31.5% vs. 38.0%) were similar in study and control groups, respectively. Patients with coasting for > or =3 days had significantly lower post-thawing embryo survival rates compared with patients having shorter duration of coasting (<3 days) and controls. Implantation and pregnancy rates, however, were similar in the three groups.

CONCLUSION(S)

Coasting did not seem to have a detrimental effect on oocyte and embryo quality because the implantation competence of transferred concept after cryopreservation and thawing was similar to that of controls. However, prolonged coasting (> or =3 days) had a subtle negative impact on the post-thaw survival rate.

[Coasting and ovarian stimulation protocols in high-responder patients undergoing assisted conception]

Over-responsive patients are at risk of ovarian hyperstimulation, which may lead to severe complications. The choice of ovarian stimulation protocol or the use of a coasting (gonadotrophins suspension) with its associated risk of too strong ovarian response will be discussed herein. As for in vitro fertilization stimulation protocols, the best are probably those which use steadily increasing low doses of gonadotrophins, associated to GnRH agonists (low-dose protocols) or those which complete a double hypophyseal inhibition (estro-progestative association and GnRH agonists). GnRH antagonists may also reduce the risk of ovarian hyperstimulation, by estradiol drop. Outside the context of in vitro fertilization GnRH continuous administration or low -dose gonadotrophin stimulation are the best options. A coasting will be performed when an excess follicle response is documented. Under strict hormonal follow-up and within four days it allows achieving a high rate of pregnancy with a lower risk of hyperstimulation. Compared to other therapies of hyperstimulation syndrome, the coasting allows to avoid cycle cancellation or freezing of all embryos.

Characteristics of populations of granulosa cells from individual follicles in women undergoing ‘coasting’ during controlled ovarian stimulation (COS) for IVF

BACKGROUND

The aim of this study was to evaluate the functional characteristics of granulosa cell populations of individual follicles of women undergoing controlled ovarian stimulation (COS) for IVF/ICSI in whom gonadotrophin had been withheld ('coasted') for the prevention of OHSS.

METHODS

Follicular fluid and granulosa cells were isolated from 224 individual follicles in 41 women who had been coasted and from 257 individual follicles in 50 women who had a 'normal' response to COS. Cells were cultured at 10,000 cells per well, to evaluate progesterone secretion. Follicular fluid was assayed for progesterone and estradiol (E2).

RESULTS

No significant differences were observed between the two groups with respect to granulosa cell number or follicular fluid progesterone and E2 and follicle size, the retrieval of an oocyte and the subsequent fertilization of the oocyte. However, the granulosa cells derived from the coasted group showed a higher rate of progesterone secretion per cell at 72 h which was sustained for longer. Differences were also seen at 72 and 120 h of culture with a loss of correlation between progesterone secretion and follicle diameter in the coasted group.

CONCLUSIONS

Our findings suggest that coasting has an effect on the functional capacity of the granulosa cells and the duration of their function. It is likely that in women at risk of OHSS who are not coasted, the granulosa cells have the capacity to produce significantly more chemical mediators per cell and for a more prolonged period of time.

Effects of coasting on the outcome of intracytoplasmic sperm injection-embryo transfer cycles

OBJECTIVES

To determine the effects of 'coasting' on the outcome of controlled ovarian hyperstimulation (COH) and intracytoplasmic sperm injection-embryo transfer (ICSI-ET).

DESIGN

Retrospective study.

SETTING

IVF Centre, Ozel Ege Tup Bebek Merkezi, Izmir, Turkey.

SAMPLE

Twenty-six coasted and 52 non-coasted COH and ICSI-ET patients were enrolled in this retrospective study.

METHODS

Coasted patients were enrolled consecutively during the study period, and two non-coasted controls were selected from our database for each coasted patient. Coasting was decided when serum oestradiol level was > or = 4000 pg/mL. Groups were compared using chi2 and Mann-Whitney U-tests for statistical analysis.

MAIN OUTCOME MEASURES

Number of oocytes collected, metaphase II (MII) oocytes and cleaving embryos, the fertilisation rate and clinical pregnancy rate were the main outcome measures.

RESULTS

Number of oocytes collected, number of MII oocytes, number of cleaving embryos, fertilisation rate and clinical pregnancy rate for the coasted and non-coasted groups were 15.5 +/- 5.2 and 14.0 +/- 7.1, 9.7 +/- 4.8 and 9.3 +/- 3.9, 6.8 +/- 3.9 and 5.8 +/- 3.1, 0.85 +/- 0.18 and 0.78 +/- 0.18, 13/26 and 24/52, respectively; these differences were not statistically significant. None of the patients in the coasted group were hospitalised for signs or findings of severe ovarian hyperstimulation syndrome.

CONCLUSIONS

Coasting does not adversely affect the number and the function of mature oocytes and the clinical pregnancy rate.

Predictors of success during the coasting period in high-responder patients undergoing controlled ovarian stimulation for assisted conception

OBJECTIVE

To determine the prognostic factors analyzed during the coasting period that can be used to predict outcomes of IVF cycles.

DESIGN

Retrospective review of data from a single center.

SETTING

Referral private IVF center.

PATIENT(S)

Three hundred forty-six patients who were coasted for the prevention of ovarian hyperstimulation syndrome (OHSS) and 262 patients who were not coasted but having excessive E(2) levels during controlled ovarian hyperstimulation for assisted conception.

INTERVENTION(S)

Controlled ovarian hyperstimulation, oocyte retrieval, intracytoplasmic sperm injection, and embryo transfer.

MAIN OUTCOME MEASURE(S)

Number of total oocytes retrieved, oocyte maturity, fertilization, implantation and pregnancy rates (IR and PR, respectively), and incidence of severe OHSS.

RESULT(S)

No difference was found between early onset coasted patients, late onset coasted patients, and uncoasted patients in terms of fertilization rates, IR, PR, and incidence of severe OHSS. Fertilization and PR did not correlate significantly with decreases in E(2) level during the coasting period. Implantation rates and PR in patients who were coasted > or =4 days were significantly reduced compared with patients who were coasted for 1-3 days. In logistic regression model, the decrease in PR with prolonged coasting was found to be significant; however, there was no correlation between decreased PR and the decrease in E(2) levels during the coasting period.

CONCLUSION(S)

Coasting can be applied safely to controlled hyperstimulation cycles without compromising the outcome. The duration of coasting seems to be a prognostic factor for the outcome of IVF. The criteria for initiation of coasting should be based on clinical experience and assessment of the patient.

Comparison of coasting and intravenous albumin in the prevention of ovarian hyperstimulation syndrome

OBJECTIVE

To compare the efficacy of coasting to prevent ovarian hyperstimulation syndrome (OHSS) with i.v. albumin and to determine if different timing of gonadotropin coasting would affect the IVF outcomes.

DESIGN

Retrospective study.

SETTING

University hospital-based IVF program.

PATIENT(S)

One hundred sixty-two women undergoing IVF treatment cycles who were considered to be at high risk for developing OHSS.

INTERVENTION(S)

Gonadotropin administration was withheld in 60 patients: either coasting occurred before follicular maturation (early coasting subset, n = 28) or follicular maturity was attained before coasting (late coasting subset, n = 32). Outcomes were compared in 102 patients at risk for OHSS who received i.v. albumin on the day of oocyte retrieval.

MAIN OUTCOME MEASURE(S)

Incidence of OHSS and outcome parameters.

RESULT(S)

Although the fertilization rates and the incidence of OHSS did not differ significantly between the coasting and i.v. albumin groups, the mean number of oocytes retrieved, the pregnancy rates, and implantation rates were significantly lower in the coasting group. There is no statistical difference in the entire outcome examined and the incidence of OHSS between the early and late coasting subsets.

CONCLUSION(S)

Coasting is as effective as i.v. albumin in preventing OHSS in high-risk patients but yields inferior pregnancy rates. Early coasting is as successful as late coasting in preventing OHSS with similar IVF outcome.

Ovarian hyperstimulation syndrome: strategies for prevention

Ovarian hyperstimulation syndrome (OHSS) is a serious, iatrogenic complication of ovarian stimulation. The following report is a review of traditional and new strategies to prevent the development of OHSS. Techniques such as reducing the ovarian stimulus, coasting and cryopreservation are discussed. Other more investigative strategies are also summarized, including follicular aspiration, in-vitro maturation of immature oocytes, the use of gonadotrophin-releasing hormone (GnRH) agonists to trigger ovulation and the use of volume expanders such as hydroxyethyl starch. In addition, a review of the internal experience with OHSS at the authors' institution is described. All these preventative approaches are based on current understanding of the physiologic mechanisms involved in the pathogenesis of OHSS.

Estradiol level on day 9 as a predictor of risk for ovarian hyperresponse during controlled ovarian hyperstimulation

PURPOSE

To investigate the estradiol (E2) level in the mid-follicular phase during controlled ovarian hyperstimulation (COH) and evaluate it as a predictor of a high risk for ovarian hyperresponse.

METHODS

From January 1996 to October 2001, the records of a total of 146 patients undergoing 164 COH cycles were retrospectively reviewed. All patients received the long protocol of GnRH agonists from the previous mid-luteal phase and then hMG or FSH from day 3 of the menstrual cycle. The E2 level was evaluated on day 9. Ovarian hyperresponse was defined as 1) an E2 level on the day of hCG injection was > 4000 pg/mL, or 2) the necessity for coasting during COH to decrease the risk of ovarian hyperstimulation syndrome (OHSS).

RESULTS

Of the 52 cycles in which day 9 E2 level was > 800 pg/mL, 29 (55.8%) fulfilled the criteria for ovarian hyperresponse. None of patients whose day 9 E2 level was < 300 pg/mL met the criteria for hyperresponse. The pregnancy rate in the groups with day 9 E2 level < 300 pg/mL was 42.9%; for an E2 level = 300-800 pg/mL, 49.2%; and for an E2 level > 800 pg/mL, 32.7%. The corresponding implantation rates were 18.8,28.0, and 17.0%. The E2 level on day 9 did not correlate with clinical pregnancy rates or implantation rates.

CONCLUSIONS

A high E2 level in the mid-follicular phase was predictive of patients with a high ovarian response. An E2 level on day 9 of menstrual cycle of > 800 pg/mL suggests an increased risk for ovarian hyperresponse, and appropriate management should be instituted to decrease the risk of OHSS.

Prevention and treatment of ovarian hyperstimulation syndrome

The ovarian hyperstimulation syndrome (OHSS) is a potentially fatal condition with a pathophysiology that is not clearly understood. A shift in fluid from the extravascular space occurs, thought to be induced by cytokines and/or vascular endothelial growth factor. Human chorionic gonadotrophin (hCG), exogenous or endogenous, seems to be the triggering mechanism, resulting in early and late development of the syndrome, respectively. The management of the syndrome is mainly symptomatic. Preventive strategies are being developed and constantly refined. Women at increased risk of OHSS need to be on the lowest possible dose of gonadotrophin with the aim of reducing the granulosa/luteal cell mass. Ultrasound and serum oestradiol (E2) measurements are, at present, the main methods used to identify and monitor those at risk during controlled ovarian hyperstimulation (COH). Withholding gonadotrophin stimulation (coasting), but continuing down-regulation, when a large number of follicles (greater than 20) and a rising serum oestradiol level are seen, is the most widely favoured and used preventive measure and the most cost effective. Management is symptomatic and aimed at achieving fluid balance, restoring plasma volume and improving renal function. This may be combined with an early resort to ascitic fluid aspiration, which will improve the feeling of wellbeing and may remove those agents responsible for the syndrome. Heparin, to prevent the risk of thromboembolism as a result of haemoconcentration, is important.

Impact of metformin therapy on ovarian stimulation and outcome in 'coasted' patients with polycystic ovary syndrome undergoing in-vitro fertilization

This study was designed to determine if metformin therapy improves ovarian stimulation and IVF outcomes in coasted patients with clomiphene-resistant polycystic ovarian syndrome (PCOS). A retrospective data analysis was performed on women with clomiphene citrate-resistant PCOS treated with or without metformin, who underwent 72 cycles of IVF-embryo transfer with intracytoplasmic sperm injection (ICSI). In 59 cycles, patients were coasted to allow oestradiol concentrations to drop before human chorionic gonadotrophin administration. In patients undergoing coasting, the outcome of IVF with ICSI was compared in those who were treated and untreated. In patients treated with metformin, follicular fluid concentrations of testosterone and insulin were significantly lower (60.5 +/- 5 versus 79.1 +/- 6 ng/dl; P < 0.05 and 18 +/- 2.5 versus 22 +/- 2.4 micro IU/ml; P < 0.05 respectively), and the mean number of oocytes retrieved (22.3 +/- 2.4 versus 19.7 +/- 1.6) did not differ. The metformin-treated group showed an increase in the mean number of mature oocytes, oocytes fertilized and cleaving embryos (4-cell or greater by 72 h). However, in the group of patients undergoing coasting, maximum oestradiol concentrations and number of days of coasting were all lower in the metformin-treated group with increased clinical pregnancy rates (71 versus 30%, P < 0.05). Therefore, metformin use appears beneficial in improving IVF outcomes in clomiphene citrate-resistant PCOS patients.

Oocyte and embryo quality after coasting: the experience from oocyte donation

BACKGROUND

Oocyte donation provides us with an opportunity to study the clinical outcome of oocytes, retrieved from women undergoing coasting, in recipients in whom endometrial receptivity is unaltered by the coasting procedure. Thus, our aim was to describe oocyte donation outcome in donors undergoing coasting, the oocyte and embryo quality obtained from these cycles, and to determine the influence of coasting duration in the cycle outcome.

METHODS

Matched-paired analysis included 15 oocyte donors with high response to ovarian stimulation and submitted to coasting and 15 oocyte donors with normal response to ovarian stimulation and not undergoing coasting. There were 38 oocyte recipients who shared oocytes from the donors under coasting and 37 from donors not undergoing coasting.

RESULTS

Both groups of donors were comparable in terms of days and dose of ovarian stimulation, oocytes retrieved, metaphase II oocytes obtained, and in the appearance of ovarian hyperstimulation syndrome. Both groups of oocyte recipients were comparable in male-associated factor, pregnancy and implantation rates, as well as in embryo quality. Recipients from donors with coasting for >4 days had significantly lower implantation and pregnancy rates.

CONCLUSIONS

the outcome of oocyte donation from donors undergoing coasting is not impaired, as good implantation and pregnancy rates are achieved. Embryo quality, according to our current standards, does not seem to be compromised by coasting itself. However, if coasting in oocyte donors is prolonged for >4 days there is a significant decrease in both implantation and pregnancy rates.

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.

"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.

A novel approach for patients at risk for ovarian hyperstimulation syndrome: elective transfer of a single zona-free blastocyst on day 5

In this preliminary prospective randomized study of 420 patients undergoing ovarian stimulation for IVF/intracytoplasmic sperm injection (ICSI), 17 patients (4%) developed moderate to severe ovarian hyperstimulation syndrome (OHSS). Re-evaluation for OHSS on day 4 and 6 after oocyte retrieval identified one patient with continuous risk for severe OHSS, resulting in cancellation of the transfer (1/17, 5.8%). Prospectively, two of three patients had the zona pellucida of the blastocyst removed by pronase exposure prior to transfer. Significantly more patients became pregnant when a zona-free blastocyst was transferred in comparison to transfer of a single zona-intact embryo (9/11 or 82% versus 1/5 or 20%; P < 0.01). Higher ongoing singleton pregnancy rates were obtained when the zona pellucida was removed prior to the transfer (6/11 and 1/5 respectively). This preliminary prospective randomized study indicates that by prolonging the evaluation time for patients at risk of developing OHSS for up to 6 days after the oocyte retrieval, those patients at risk for developing severe OHSS can be identified. Transferring a single zona-free day 5 embryo (blastocyst) and freezing of the supernumerary embryos offers the patient with moderate OHSS an optimal chance for a singleton pregnancy, while avoiding the serious maternal complications of ovarian hyperstimulation syndrome.

Preventive attitude of physicians to avoid OHSS in IVF patients

The ovarian hyperstimulation syndrome (OHSS) is a dramatic iatrogenic complication of fertility treatment. There is no consensus about its prevention strategies. We assessed whether physicians modify their preventive attitude in relation to clinical risk factors and to the oestradiol response chart. Three case scenarios with three levels of risk factors for OHSS were constructed. For each case scenario, four different charts of the oestradiol curve were described (peak serum oestradiol of 3590 or 6590 pg/ml obtained after a shorter or longer period). At random, we sent three out of the 12 artificially constructed case scenarios to 573 physicians who are members of the European Society of Human Reproduction and Embryology (ESHRE). They were asked whether they would cancel the cycle, take preventive measures or proceed to a regular IVF. A total of 389 cases from 130 different physicians was analysed. Globally, in 23% of the cases the physicians would proceed to a regular IVF. This decision varied significantly according to the risk level (between 38% in low risk to 8% in high risk cases; P < 0.01) and in relation to the oestradiol curve (P < 0.01). In 11% of the cases they would cancel the cycle and in 66% take some preventive measures. Among the selected preventive measures, coasting was by far the most popular choice (60%), followed by the use of i.v. albumin or hydroxyaethyl starch solution (36%) and cryo-preservation of all embryos (33%). In view of the sparse data as to whether coasting is really an effective method, and on how it should be carried out, we suggest that there is an urgent need to evaluate coasting as a preventive method in a large randomized trial in order to properly assess its efficiency and to provide precise guidelines for its use.

Combined approach as an effective method in the prevention of severe ovarian hyperstimulation syndrome

The purpose of this study was to evaluate the effectiveness of combined approach on the prevention of severe ovarian hyperstimulation syndrome (OHSS) in high risk patients undergoing controlled ovarian hyperstimulation for IVF. The combined approach consisted of: (1) step-down administration of gonadotropins; (2) lowering the dose of human chorionic gonadotropin; (3) intravenous albumin infusion at the time of oocyte retrieval and (4) progesterone use for luteal support. Total of 87 high risk patients with a serum estradiol level >11,010 pmol/l or 3000 pg/ml on HCG day were managed by this combined approach and their results were compared with 274 low risk patients. In all high risk patients, the gonadotrophin dose were decreased starting as early as on day 4 of ovarian stimulation as necessary, ovulation was triggered by a decreased HCG dose of 5000-7000 IU according to the level of estradiol, intravenous infusion of 20% human albumin, 50-100ml were given just 1h before the oocyte retrieval and luteal support was provided either by 50mg progesterone in oil, IM or 600 mg micronized progesterone orally or vaginally until the day of beta-HCG determination. All patients were followed by serial ultrasonographic examinations and complete blood count analysis after embryo transfer to detect the early signs of OHSS and to allow early intervention. Age and duration of infertility were similar in both groups. Although the number of gonadotrophin ampoules used (22.7 +/- 4.7 versus 27.8+/-3.7; P<0.05) was significantly lower, estradiol levels (16,764 +/- 6936 pmol/l versus 8870 +/- 2456 pmol/l; P<0.05) and mean number of oocytes (18.3 +/- 5.9 versus 10.6+/-5.4; P<0.05) were significantly higher in study group. There was no significant difference between groups in terms of the mean number of transferred embryos (3.2 +/- 1.1 versus 3.4+/-1.1) and rate of pregnancies (50.5% versus 40.1%). There was only one moderate and no severe OHSS case in the high risk group, while five moderate and one severe OHSS cases developed in the control group consisting of low risk patients. In conclusion, intravenous albumin combined with low dose HCG, early step-down administration of gonadotropins and progesterone use for luteal support, so called combined approach, proved to be effective in the prevention of severe ovarian hyperstimulation syndrome in documented high risk patients.