Methods employed to overcome difficult embryo transfer during assisted reproduction treatment

Multiple steps, at both scientific and clinical level, are involved in assisted reproduction technology (ART). Optimization of each of these steps contributes to maximize the success of ART. Embryo transfer is one of the vital steps in ART. An easy embryo transfer increases the success of ART. Adequate training is required to undertake embryo transfer, but anatomical difficulties in completing this procedure alter the success of treatment. Difficult embryo transfer is challenging for clinicians but has an overwhelming negative impact on patients. Difficult embryo transfer may cause cervical or endometrial trauma with uterine contractions which can lead to unsuccessful implantation and poor outcome after ART. Literature review of published material looking at all interventions that were employed to overcome difficult embryo transfers during ART. We identified 5 methods (17 studies) were employed to overcome difficult embryo transfer which are: Hysteroscopic methods in 4 studies (2 case reports, 2 case series). Malecot catheters after hysteroscopic evaluation were used in 2 studies (1 case report, 1 case series). Dilators including hygroscopic dilators were used in 2 studies (1 case report, 1 case series) and mechanical dilators were used in 3 studies (2 case series, 1 RCT-patients 367). Intrafollopian transfer was reported in 1 case report. Transmyometrial embryo transfers were reported in 5 studies (2 case reports, 2 case series, 1 RCT). There were only two randomized controlled studies (RCTs) identified in the review. All other were either case series or case reports. We found that there was no uniform classification or grading of difficulty of embryo transfer in the literature. A grading system has been suggested in this review. We recommend that there should be a consensus guideline formulated for interventions to overcome difficult embryo transfer. A large multicenter randomized controlled study is required to compare different methods for women with difficult embryo transfer.