What is Implantation Failure after <em>In Vitro</em> Fertilization and Embryo Transfer?

Special Article – In Vitro Fertilisation

Austin J Obstet Gynecol. 2016; 3(3): 1063.

What is Implantation Failure after In Vitro Fertilization and Embryo Transfer?

Coulam CB*, Goodman C, Chapman C and Rinehart JS

Reproductive Medicine Institute, USA

*Corresponding author: Coulam CB, Reproductive Medicine Institute, Chicago, IL, USA

Received: October 10, 2016; Accepted: November 23, 2016; Published: November 25, 2016

Abstract

Problem: Recurrent Implantation Failure (RIF) is a major cause of failure to achieve pregnancy after In Vitro Fertilization (IVF) and embryo transfer treatment cycles. However, no formal criteria defining the number of failed cycles or the total number of embryos transferred in these IVF attempts exist.

Methods: From January 1, 2014, and June 30, 2015, 644 women underwent IVF or embryo transfer procedures involving 2093 embryos. 427 women had positive HCG tests 7 days after transfer of 1364 embryos, resulting in 381 Embryonic Cardiac Activity (ECA) demonstrated by 6 weeks gestation. Of the 381 positive ECA, 55 had Preimplantation Genetic Screening (PGS) and 326 had no PGS. The percentage of pregnancies with demonstrable ECA was determined for each number of embryos transferred, and cumulative pregnancy rates for those undergoing PGS and not undergoing PGS were computed. In addition, the cumulative pregnancy rates were stratified by maternal age.

Results: The total number of embryos transferred to achieve 80% of pregnancies with FHT is 4. The rate of ECA after 1 embryo transferred double from 13% to 29% with PGS. Whereas, after a cumulative of 4 embryos transferred the rate of ECA was 75% amongst PGS and 82% with no PGS. When stratified by maternal age, older women benefited most by PGS.

Conclusion: The total number of embryos transferred to achieve 80% of pregnancies with ECA is 4. After a cumulative of 4 embryos transferred, PGS does not increase probability of successful pregnancy except in women over age 40 years.

Keywords: Recurrent implantation failure; Definition; Cumulative number of embryos transferred

Introduction

Recurrent Implantation Failure (RIF) occurs when transferred embryos fail to implant following a number of In Vitro Fertilization (IVF) treatment cycles [1,2]. However, there are no formal criteria defining the number of failed cycles or the total number of embryos transferred in these IVF attempts. As a result different fertility centers practicing IVF use different definitions for RIF [1-4] making it difficult to identify individuals who would be expected to continue to experience failure of implantation. Since the processes of implantation are complex, assessing causes of RIF can involve substantial resources. Thus, identifying individuals most likely to be benefited from such investigations would be desirable.

Successful implantation is a complex process involving two main players- a functional embryo at the blastocyst stage and a receptive endometrium [5]. Synchronized cross-talk between embryo and endometrium is necessary for apposition, attachment and invasion of embryos leading to successful implantation [6]. The mechanisms involved in the cross-talk require many mediators originating in the embryo, as well as in the endometrium [6-9]. Chromosomal abnormalities occurring within the embryo have been shown to account for up to 60% of RIF [10]. To answer the question “What is implantation failure in our practice?” outcomes of unselected consecutive IVF procedures performed between January 1, 2014 and June 30, 2015 were analyzed to determine the cumulative number of embryos needed to achieve 80% probability of pregnancy with demonstrated Embryonic Cardiac Activity (ECA). IVF outcomes after transfer of embryos that had undergone Preimplantation Genetic Screening (PGS) were compared with those not having PGS.

Materials and Methods

From January 1, 2014, and June 30, 2015, 644 women underwent IVF or embryo transfer procedures involving 2093 embryos. 427 (66%) women had positive HCG tests 7 days after transfer of 1364 embryos, resulting in 381 (59% of patients, 89% of positive HCG) ECA demonstrated by 6 weeks gestation. Of the 381 positive ECA, 55 had Preimplantation Genetic Screening (PGS) and 326 had no PGS. The percentage of pregnancies with demonstrable ECA was determined for each number of embryos transferred, and cumulative pregnancy rates were computed. Cumulative pregnancy rates were compared between those embryos undergoing PGS and those not screened with PGS. In addition, cumulative pregnancy rates were stratified by maternal age. Differences were compared using ANOVA one way analysis of variance. Significance was defined as p<0.05.

Results

Cumulative rates to achieve fetal cardiac activity compared with total number of embryos transferred are shown in (Figure 1). The rate of ECA after 1 embryo transferred double from 13% to 29% with PGS. Whereas, after a cumulative of 4 embryos transferred the rate of ECA was 75% amongst PGS and 82% with no PGS. These differences in rate of positive ECA are significant at P=0.005. After a cumulative of 4 embryos transferred, PGS does not increase probability of successful pregnancy.