Soluble human leukocyte antigen G expression in phase I culture media at 46 hours after fertilization predicts pregnancy and implantation from day 3 embryo transfer.

Objective: To compare pregnancy and implantation rates after ART when embryos for day 3 embryo transfer were selected based on soluble HLA-G (sHLA-G) expression in the culture media at 46 hours after fertilization by intracytoplasmic sperm injection (ICSI).

Design: Prospective cohort study.

Setting: Private practice.

Patient(s): One hundred seven patients undergoing ART aged <39 years with normal ovarian reserve, a normal uterine cavity, and two or more embryos scoring > or =70 by the graduated embryo scoring (GES) method, transferred on day 3.

Intervention(s): Patients were divided into two groups. In group A (n = 51) all embryos transferred expressed sHLA-G above the geometric mean (sHLA-G+), whereas in group B (n = 56) all embryos transferred were sHLA-G-ve.

Main Outcome Measure(s): Viable pregnancy rate (patients with fetal heart activity at 8 weeks of gestation per embryo transfer procedure), and implantation rate (viable gestational sacs per total embryos transferred).

Result(s): When all embryos transferred were sHLA-G+ve the pregnancy and implantation rates were 75% (38/51) and 44% (51/116), respectively, compared to 23% (13/56) and 14% (20/143) when all embryos transferred were sHLA-G-ve.

Conclusion(s): Pregnancy and implantation rates after day 3 embryo transfer are improved when sHLA-G expression in phase I culture media at 46 hours after fertilization by ICSI is used prospectively as a criterion for selecting optimal embryos for transfer.