Association between follicle size, endometrial thickness, and types of ovarian stimulation (Clomiphene citrate and Letrozole) with biochemical pregnancy rate in women undergone intrauterine insemination

OBJECTIVE: There was also a lack of data regarding the effect of follicle size, endometrial thickness, and ovarian stimulation as predictors of intrauterine insemination (IUI) success rate in Indonesia, especially in the Aster Clinic and Bandung Fertility Centre. This study was performed to explore the relationship between follicle size, endometrial thickness, and types of ovarian stimulation (Clomiphene citrate/CC vs Letrozole) with biochemical pregnancy rate in women undergone IUI. We performed a case–control study in 122 women aged 20–40 years with unexplained infertility who had completed the IUI program for a maximum of three cycles. Data were extracted from medical records. Independent T-test and multivariate analyses were used to analyse the difference between variables using IBM SPSS 24.0. P-value < 0.05 was considered statistically significant. RESULT: Follicle sizes of 18–22 mm in both Clomiphene citrate (CC) and Letrozole groups were shown to increase biochemical pregnancy rate (P = 0.001). There is no relationship between endometrial thickness and pregnancy rate. Biochemical pregnancy rate in women using Letrozole was 1.513 times higher than women using CC. The follicle size of 18–22 mm and using Letrozole rather than CC as ovarian stimulators are predictive factors associated with a higher pregnancy rate in women undergone IUI.