Fertility is a fundamental function of reproductive health that is under the control of different hormones, cytokines, and growth factors. Transforming growth factor superfamily is a group of cytokines necessary for blastocyst implantation as they regulate endometrial stromal cell proliferation, and promote embryonic adherence to the receptive endometrium. Hyaluronic acid molecule (HA) is a long, unbranched polysaccharide that plays a delicate function in reproduction. Hyaluronic acid regulates gametogenesis, folliculogenesisi, and implantation, thereby was oroposed to improve the rate of successful pregnancy.This study is a prospective clinical trial that includes 80 infertile Iraqi women aged (18-40 years) scheduled for fresh ICSI program. The study sample had been divided into 2 groups based on the type of intervention performed on the day of oocytes retrieval. The Hyaluronic acid group and the control group. For each participant, twice measurement of the serum level of transforming growth factor were done , the first measure was done on day of oocytes retrieval, while the second measure was performed on day of embryo transfer. A comparative statistic was made to examine the effect of hyaluronic acid intrauterine wash on the serum level of transforming growth factor and pregnancy rate.Hyaluronic acid intrauterine wash exerts a significant reduction in transforming growth factor serum level, and a significant improvement in the pregnancy outcome compared to the control group.