PHYSIOLOGICAL AND HORMONAL PREDICTORS OF IMPLANTATION SUCCESS IN WOMEN UNDERGOING OVULATION INDUCTION

Abstract

Background: The implantation process is extremely important during establishment of pregnancy, and can be influenced by maternal, ovarian, hormonal, follicular, and endometrial factors. Ovulation induction can be employed to enhance the chances of conception for women with infertility; however, successful ovulation does not always lead to implantation. The identification of reliable predictors may help to better counsel and plan patient treatment. Objective: To evaluate physiological and hormonal predictors of implantation success in women undergoing ovulation induction. Methods: A prospective observational study was conducted at Liaqat Memorial Hospital, Kohat, from April 2025 to October 2026. A total of 89 women who were undergoing ovulation induction were included. Demographic parameters, factors related to infertility, ovarian reserve markers, hormonal parameters, follicular development, endometrial parameters and treatment-related variables were recorded. The serum β-hCG was used to evaluate the success of the implantation after the induction cycle. The participants were divided into successful and unsuccessful implantation groups. Group comparisons were made with appropriate tests and multivariable binary logistic regression was used to determine independent predictors of implantation success. A p-value <0.05 was considered statistically significant. Results: Successful implantation occurred in 36 women (40.4%), while 53 (59.6%) had unsuccessful implantation. Women with successful implantation were younger and had lower BMI and shorter infertility duration. They also demonstrated significantly higher AMH, trigger-day estradiol, and mid-luteal progesterone levels, whereas baseline FSH was lower. Successful implantation was additionally associated with greater antral follicle count, larger dominant follicle diameter, a higher number of mature follicles, increased endometrial thickness, and a trilaminar endometrial pattern. On multivariable analysis, younger age, higher AMH, higher mid-luteal progesterone, larger dominant follicle diameter, and greater endometrial thickness remained significant independent predictors of successful implantation. Conclusion: Implantation success following ovulation induction is influenced by multiple physiological and hormonal factors. Younger maternal age, favorable ovarian reserve, adequate luteal progesterone, appropriate follicular maturation, and greater endometrial thickness appear to be important predictors. Combined assessment of these parameters may assist in individualized fertility treatment and estimation of implantation probability.