Abstract: 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. 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.

Plain-language summary: Study characteristics: we included six randomised controlled trials conducted in the UK, France, Spain, Israel and the US, including 781 women. They compared monitoring with TVUS only versus TVUS plus serum estradiol concentration in women undergoing ovarian hyperstimulation for IVF and ICSI treatment. The evidence was current to May 2014. Key results: 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 between monitoring with TVUS only and monitoring with TVUS plus estradiol measurement (odds ratio (OR) 1.10; 95% CI 0.79 to 1.54; four studies; N = 617; I² = 5%; low quality evidence). Our findings suggest 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 in OHSS between the two arms (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 TVUS only was between 2% and 8%. Quality of the evidence: the evidence was of low quality. Limitations included imprecision and potential bias due to unclear randomisation methods, allocation concealment and blinding, as well as differences in the treatment protocols. Quality assessment was hampered by a lack of methodological descriptions in several studies. Two studies reported funding by pharmaceutical companies, whereas the remaining four studies did not report their sources of funding.