The impact of endometrial thickness (EMT) on the day of human chorionic gonadotropin (hCG) administration on pregnancy outcomes: a 5-year retrospective cohort analysis in Malaysia.

Abstract

Background: Chances of pregnancy in relation to endometrial thickness (EMT) remain elusive albeit some literatures suggest poorer pregnancy outcomes below the threshold of 6-7 mm, notwithstanding others perceive detrimental effect at thicker EMT. We aim to examine the implication of EMT on pregnancy outcomes using a cut-off of 8 mm and further explore for any effect of 'thick' EMT in our patient population.

Methods: This was a retrospective cohort study performed for 162 women to assess the associations between EMT on the human chorionic ganadotropin (hCG) trigger day and pregnancy outcomes in infertile patients undergoing in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) and autologous fresh embryo transfer (ET) in controlled ovarian stimulation (COS) cycles under an assisted reproductive technology (ART) shared-care programme between public and private institutions from January 2012 through December 2016.The associations between pregnancy outcomes [Total Pregnancy Rate (TPR), Biochemical Pregnancy Rate (BPR), Clinical Pregnancy Rate (CPR), Ongoing Pregnancy Rate (OPR)/ Live Birth Delivery Rate (LBDR), Miscarriage Rate (MR) and Implantation Rate (IR)] and EMT (< 8 or ≥ 8 mm) on the hCG trigger day were evaluated. Besides, the associations between pregnancies outcomes with EMT ≥ 14 mm and ≥ 8 to < 14 mm were further assessed.

Results: We found that the ≥8 mm group had a higher TPR (55.4% vs 21.4%; p = 0.015) and CPR (52.0% vs 21.4%; p = 0.029). However, the BPR, MR, OPR/ LBDR and IR were not associated with the EMT (p > 0.05). All pregnancy outcomes were comparable for ≥14 mm and ≥ 8 to < 14 mm subgroups.

Conclusions: Our findings suggest that EMT < 8 mm on hCG trigger day could adversely affect TPR and CPR in infertile patients undergoing IVF/ICSI-ET. Besides, we also disprove the notion of reduced chances of pregnancy with EMT ≥ 14 mm. The findings are based on completed cycles which each has demonstrated a triple-line endometrial pattern on the hCG trigger day with fresh autologous ET consisted of high-quality morphological gradings. However, our findings are still preliminary to suggest decision for ET transfer, cycle cancellation or adjunctive therapies. Further studies with larger sample size from this geographical region are required to verify the findings.