Evaluation of a high implantation potential (HIP) embryo grading system designed to reduce multiple pregnancy

Abstract

Aims

Although we have progressed a long way in performing in vitro fertilization, one hurdle that still remains is the assessment of embryos. The aim of the current paper was to evaluate an embryo selection protocol based on the presence of high implantation potential (HIP) embryos on Day 3 embryo transfer outcomes.

Methods

The analysis of cycles from 6573 IVF cycles in a private fertility clinic was done. Patients included IVF couples having day 3 embryos transferred. Rates of clinical pregnancy, twinning, and high order multiples (HOM) were investigated.

Results

When one or more HIP embryos were present in the cohort, there were no significant differences in clinical pregnancy rates when the decision was made to reduce the scheduled number of embryos to transfer by 1, that is, when comparing 2 embryos transferred with 2 reduced to 1, 3 with 3 reduced to 2, or 4 with 4 reduced to 3. Twinning rates were the same when at least 2 embryos were transferred and high order multiple rates were not different when at least 3 embryos were transferred. The presence of HIP embryos increases the chance of pregnancy when 1–2 embryos are transferred. With 3–4 embryos, the presence or absence of a HIP embryo becomes less of a factor in establishing pregnancy.

Conclusions

Selecting HIP embryos can reduce the number of embryos transferred without adversely affecting pregnancy rates. Their presence is a strong predictor of pregnancy in patients ≤37 years old.