Ovarian hyperstimulation syndrome: clinical features, prevention and management

The Association between Ovarian Hyperstimulation Syndrome and Pregnancy Complications following Fertility Treatments

OBJECTIVE

 This study was aimed to assess the association between ovarian hyperstimulation syndrome (OHSS) and pregnancy complications among women who conceived following fertility treatment.

STUDY DESIGN

 A retrospective population-based cohort study, including all singleton deliveries of patients conceived following ovulation induction (OI) or in vitro fertilization (IVF) between 1988 and 2016, was conducted. All births occurred in a single tertiary medical center. A comparison was performed between deliveries of women who had experienced OHSS at early gestation and subsequently had a pregnancy and women without OHSS. Women lacking prenatal care, multiple gestations, and stillbirths were excluded from the analyses. A multivariable logistic regression model was used to control for confounders.

RESULTS

 During the study period, 351,373 deliveries met the inclusion criteria, of which 6,748 were deliveries of infants who were conceived by either IVF or OI. Of this study population, 105 cases (1.6%) composed the exposed group, that is, women who had experienced OHSS with a subsequent live birth. In the multivariate analyses, after controlling for confounders, OHSS was not found as an independent risk factor for preeclampsia, gestational diabetes mellitus (GDM), intrauterine growth restriction (IUGR), preterm delivery (both <37 and <34 weeks), low birth weight (LBW), very LBW (VLBW), small for gestational age (SGA), and caesarean delivery. In a subanalysis conducted solely on the IVF population, similar results were found, aside from the association between OHSS and preterm delivery before 34 weeks of gestation which was statistically significant (adjusted odds ratio [AOR] = 2.3 95% confidence interval [CI]: 1.0-5.3, p = 0.049).

CONCLUSION

 In our population, OHSS was not found as a risk factor for adverse pregnancy and perinatal outcome. In IVF patients, OHSS is a risk factor for preterm delivery before 34 weeks of gestation.

KEY POINTS

· OHSS is not a risk factor for pregnancy complications.. · Complications investigated were preeclampsia, GDM, prematurity, and others.. · In IVF patients, OHSS is a risk factor for preterm delivery..

Monitoring of stimulated cycles in assisted reproduction (IVF and ICSI)

BACKGROUND

Monitoring of in vitro fertilisation (IVF) and intra-cytoplasmic sperm injection (ICSI) is necessary to detect as well as reduce the incidence and severity of ovarian hyperstimulation syndrome (OHSS) whilst achieving the optimal ovarian response needed for assisted reproduction treatment. Traditional monitoring of ovarian hyperstimulation during in vitro fertilisation IVF and ICSI treatment has included transvaginal ultrasonography (TVUS) plus serum estradiol levels. The need for combined monitoring (using TVUS and serum estradiol) during ovarian stimulation in assisted reproduction is controversial. It has been suggested that combined monitoring is time consuming, expensive and inconvenient for women and that simplification of IVF and ICSI therapy by using TVUS only should be considered.  OBJECTIVES: To assess the effect of monitoring controlled ovarian hyperstimulation (COH) in IVF and ICSI cycles in subfertile couples with TVUS only versus TVUS plus serum estradiol concentration, with respect to rates of live birth, pregnancy and OHSS.

SEARCH METHODS

In this update conducted in March 2020, two review authors searched the Cochrane Gynaecology and Fertility Group's Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL, PsycINFO, the National Research Register, and web-based trial registers. There was no language restriction applied. All references in the identified trials and background papers were checked and authors were contacted to identify relevant published and unpublished data.

SELECTION CRITERIA

Only randomised controlled trials that compared monitoring with TVUS only versus TVUS plus serum estradiol concentrations in women undergoing COH for IVF and ICSI treatment were included.

DATA COLLECTION AND ANALYSIS

Two review authors (IK, AW) independently selected the studies, extracted data and assessed risk of bias. We resolved disagreements by discussion. Outcomes data were pooled and summary statistics were presented when appropriate. The quality of the evidence was rated using the GRADE methods.

MAIN RESULTS

We did not identify any new eligible studies in this update in 2020. The evidence based on the six trials identified in 2014 remained unchanged. They included 781 women undergoing monitoring of COH with either TVUS alone or a combination of TVUS and serum estradiol concentration during IVF or ICSI treatment. None of the six studies reported our primary outcome of live birth rate. Two studies presented pregnancy rate per initiated cycle and per embryo transfer, respectively. Four studies reported pregnancy rate per woman with pooled data; we are uncertain of the effect of monitoring with TVUS only versus combined monitoring on clinical pregnancy rate per woman (odds ratio (OR) 1.10; 95% confidence interval (CI) 0.79 to 1.54; four studies; N = 617; I² = 5%; low quality evidence). This suggests in women with a 36% chance of clinical pregnancy using monitoring with TVUS plus serum estradiol, the clinical pregnancy rate using TVUS only would be between 31% and 46%. We are uncertain of any effect in the mean number of oocytes retrieved per woman (mean difference (MD) 0.32; 95% CI -0.60 to 1.24; five studies; N = 596; I² = 17%; low quality evidence).  We are uncertain whether monitoring with TVUS only versus combined monitoring affected the incidence of OHSS (OR 1.03; 95% CI 0.48 to 2.20; six studies; N = 781; I² = 0%; low quality evidence), suggesting that in women with a 4% chance of OHSS using monitoring with TVUS plus serum estradiol, the OHSS rate monitored by TVUS only would be between 2% and 8%. The cycle cancellation rate was similar in both arms of two studies (0/34 versus 1/31, 1/25 versus 1/25; OR 0.57; 95% CI 0.07 to 4.39; N = 115; I² = 0%; low quality evidence).  The evidence was low quality for all comparisons. Limitations included imprecision and potential bias due to unclear randomisation methods, allocation concealment and blinding, as well as differences in treatment protocols. Quality assessment was hampered by the lack of methodological descriptions in several studies.

AUTHORS' CONCLUSIONS

This review update found no new randomised trials. Evidence from the six studies previously identified did not suggest that combined monitoring by TVUS and serum estradiol is more efficacious than monitoring by TVUS alone with regard to clinical pregnancy rates and the incidence of OHSS. The number of oocytes retrieved appeared similar for both monitoring protocols. The data suggest that both these monitoring methods are safe and reliable. However, these results should be interpreted with caution because the overall quality of the evidence was low. Results were compromised by imprecision and poor reporting of study methodology. The choice of one or the other method may depend upon the convenience of its use, and the associated costs. An economic evaluation of the costs involved with the two methods and the views of the women undergoing cycle monitoring would be welcome.

Monitoring of stimulated cycles in assisted reproduction (IVF and ICSI)

BACKGROUND

Traditional monitoring of ovarian hyperstimulation during in vitro fertilisation (IVF) and intra-cytoplasmic sperm injection (ICSI) treatment has included transvaginal ultrasonography (TVUS) plus serum estradiol levels to ensure safe practice by reducing the incidence and severity of ovarian hyperstimulation syndrome (OHSS) whilst achieving the good ovarian response needed for assisted reproduction treatment. The need for combined monitoring (using TVUS and serum estradiol) during ovarian stimulation in assisted reproduction is controversial. It has been suggested that combined monitoring is time consuming, expensive and inconvenient for women and that simplification of IVF and ICSI therapy by using TVUS only should be considered.

OBJECTIVES

To assess the effect of monitoring controlled ovarian hyperstimulation (COH) in IVF and ICSI cycles in subfertile couples with TVUS only versus TVUS plus serum estradiol concentration, with respect to rates of live birth, pregnancy and OHSS.

SEARCH METHODS

We searched the Menstrual Disorders and Subfertility Group Specialised Register of controlled trials, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, PsycINFO, the National Research Register, and web-based trial registers such as Current Controlled Trials. The last search was conducted in May 2014. There was no language restriction applied. All references in the identified trials and background papers were checked and authors were contacted to identify relevant published and unpublished data.

SELECTION CRITERIA

Only randomised controlled trials that compared monitoring with TVUS only versus TVUS plus serum estradiol concentrations in women undergoing COH for IVF and ICSI treatment were included.

DATA COLLECTION AND ANALYSIS

Three review authors independently selected the studies, extracted data and assessed risk of bias. They resolved disagreements by discussion with the rest of the authors. Outcomes data were pooled and summary statistics were presented when appropriate. The quality of the evidence was rated using the GRADE methods.

MAIN RESULTS

With this update, four new studies were identified resulting in a total of six trials including 781 women undergoing monitoring of COH with either TVUS alone or a combination of TVUS and serum estradiol concentration during IVF or ICSI treatment.None of the six studies reported our primary outcome of live birth rate. Pooled data showed no evidence of a difference in clinical pregnancy rate per woman between monitoring with TVUS only and combined monitoring (odds ratio (OR) 1.10; 95% confidence interval (CI) 0.79 to 1.54; four studies; N = 617; I² = 5%; low quality evidence). This suggests that compared with women with a 34% chance of clinical pregnancy using monitoring with TVUS plus serum estradiol, the clinical pregnancy rate in women using TVUS only was between 29% and 44%.There was no evidence of a difference between the groups in the reported cases of OHSS (OR 1.03; 95% CI 0.48 to 2.20; six studies; N = 781; I² = 0%; low quality evidence), suggesting that compared with women with a 4% chance of OHSS using monitoring with TVUS plus serum estradiol, the OHSS rate in women monitored by TVUSS only was between 2% and 8%.There was no evidence of a difference between the groups in the mean number of oocytes retrieved pre woman (mean difference (MD) 0.32; 95% CI -0.60 to 1.24; five studies; N = 596; I² = 17%; low quality evidence).The evidence was low quality for all comparisons. Limitations included imprecision and potential bias due to unclear randomisation methods, allocation concealment and blinding, as well as differences in treatment protocols. Quality assessment was hampered by the lack of methodological descriptions in several studies.

AUTHORS' CONCLUSIONS

This review update found no evidence from randomised trials to suggest that combined monitoring by TVUS and serum estradiol is more efficacious than monitoring by TVUS alone with regard to clinical pregnancy rates and the incidence of OHSS. The number of oocytes retrieved appeared similar for both monitoring protocols. The data suggest that both these monitoring methods are safe and reliable. However, these results should be interpreted with caution because the overall quality of the evidence was low. Results were compromised by imprecision and poor reporting of study methodology. A combined monitoring protocol including both TVUS and serum estradiol may need to be retained as precautionary good clinical practice and as a confirmatory test in a subset of women to identify those at high risk of OHSS. An economic evaluation of the costs involved with the two methods and the views of the women undergoing cycle monitoring would be welcome.