Effect of assisted hatching on pregnancy outcomes: a systematic review and meta-analysis of randomized controlled trials

Abstract

Emerging evidence suggests that assisted hatching (AH) techniques may improve clinical pregnancy rates, particularly in poor prognosis patients; however, there still remains considerable uncertainty. We conducted a meta-analysis to verify the effect of AH on pregnancy outcomes. We searched for related studies published in PubMed, Web of Science, and Cochrane library databases from start dates to October 10, 2015. Totally, 36 randomized controlled trials with 6459 participants were included. Summary odds ratios (ORs) with 95% confidence intervals (CIs) for whether by AH or not were estimated. We found a significant increase in clinical pregnancy (OR = 1.16, 95% CI = 1.00–1.36, I2 = 48.3%) and multiple pregnancy rates (OR = 1.50, 95% CI = 1.11–2.01, I2 = 44.0%) with AH when compared to the control. Numerous subgroup analyses stratified by hatching method, conception mode, extent of AH, embryos transfer status, and previous failure history were also carried out. Interestingly, significant results of clinical pregnancy as well as multiple pregnancy rates were observed among women who received intracytoplasmic sperm injection, and who received AH which the zona were completely removed. In summary, this meta-analysis supports that AH was associated with an increased chance of achieving clinical pregnancy and multiple pregnancy. Whether AH significantly changes live birth and miscarriage rates needs further investigations.

Assisted hatching and live births in first-cycle frozen embryo transfers

“…Asian, African Americans, and Hispanic ethnicities were more likely to receive AH compared to Caucasians. Previous studies focused on “poor prognosis” patients are limited by small numbers and heterogeneity in the definition of “poor prognosis.”(3, 8) Further studies are needed to evaluate these influences on AH.…”

“…A recent meta-analysis identified 36 randomized studies assessing AH, however only 8 studies pertained to AH with frozen-thawed embryos and they found no significant difference in clinical pregnancy or live birth. (3) In the current study, propensity matching allowed for a matched set of comparable recipients with and without AH.…”

“…The majority of the data in randomized clinical trials, reviews, and meta-analyses use clinical pregnancy as the primary outcome. (2, 3) However, clinical pregnancy is only a surrogate measure for the ultimate end point of live birth. From 1992 to 2009, there have been 15 trials investigating live birth rate (LBR) and AH with only 420 live births reported from these small trials.…”

“…From 1992 to 2009, there have been 15 trials investigating live birth rate (LBR) and AH with only 420 live births reported from these small trials. (3, 4) Given the limited number of studies, the American Society of Reproductive Medicine guidelines conclude that there is insufficient evidence that AH improves live births. (4)…”

Adjuncts in the IVF laboratory: where is the evidence for ‘add-on’ interventions?

“…There was no evidence of difference between the LBR in the AH and control groups. Li et al, (2016) looked at 36 RCTs with 6,459 participants and found that AH gave a significant increase in CPR and multiple pregnancy rate but in the 15 RCTs that looked at LBR, there was no evidence of difference between the AH and control groups.…”