The relationship of serum and follicular fluid pregnancy-associated plasma protein (PAPP-A) levels with endometrial thickness in PCOS and non-PCOS women undergoing ICSI-cycles

Abstract

Pregnancy-associated plasma protein (PAPP-A) is a metalloproteinase that binds and cleaves insulin-like growth factor-binding protein 4 (IGFBP4), then releases IGF-1 from the IGFBP4/IGF-1 complex, activating the IGF pathway. As a result, in the IGF system, PAPP-A is regarded as a bioactive IGF-1 enhancing enzyme. IGFs and IGF receptors are thought to play a role in endometrium receptivity. A critical endometrium receptivity biomarker was up-regulated by PAPP-A. The present study aimed to assess the relationship of PAPP-A levels in serum and follicular fluid with endometrial thickness in PCOS and non PCOS women enrolled in the ICSI cycle. Forty-five infertile Iraqi women with PCOS and non-PCOS criteria were nominated from those who were attending the Higher Institute for Infertility Diagnosis and Assisted Reproductive Technologies clinic. The age of the included women ranged between 20-45 years. PAPP-A level measures in serum (at pick-up day and embryo transfer day) and follicular fluid. In non-PCOS patients, PAPP-A has higher level in serum and follicular fluid but without statistically significant difference comparing with PCOS patients. Level of PAPP-A and endometrial thickness increased significantly at the day of embryo transfer in contract with pick up day. The result did not show any correlation between PAPPA levels and endometrial thickness in both days. While, there was insignificant increase in endometrial thickness at both pick up and transfer days between pregnant and non-pregnant women. In conclusion, level of PAPP-A (in serum and follicular fluid) and endometrial thickness at the time of embryo transfer were significantly higher than pick-up day, this study did not establish a statistical significant relationship between serum and follicular fluid in PAPP-A levels and endometrial thickness.