Patients were divided randomly into two groups at the time
Patients were divided randomly into two groups at the time of hCG administration. Patients in Group 1 (n = 38; 33.6%) underwent IUI 24 hours after hCG administration. Group 2 (n = 75; 66.4%) underwent IUI 36 hours after hCG administration. All patients were instructed to have intercourse when the dominant follicle reached a diameter of approximately 16 mm and 12 hours after insemination. Following the transfer, the patients received 200 mg/day vaginal progesterone supplementation for luteal support until 12 weeks of gestational age if the patient conceived. Qualitative serum β-hCG test was performed 14 days after insemination if menstruation had not started. A clinical pregnancy was defined as the presence of a gestational sac with accompanying fetal cardiac activity by ultrasound at least 4 weeks after insemination. The demographic features, infertility types, dominant follicle number, endometrial thickness on hCG day, timing of intrauterine insemination, and clinical pregnancy rates of the patients have been evaluated. Statistical analysis was performed as follows: normal distribution of data was evaluated using the Kolmogorov–Smirnov test. The continuous variables were presented as means ± standard deviation and compared using the independent samples t test. The nonparametric variables and data without normal distribution were tested using the Mann–Whitney U test, and correlation analysis was performed using Spearman\'s correlation test. The comparison of categorical values was made utilizing Fisher\'s exact test or Chi-square test. A p value < 0.05 were considered statistically significant.
Results The AP20187 outcomes of patients who underwent IUI procedures 24 hours and 36 hours following hCG trigger after ovulation induction with gonadotropin treatment are presented in Table 1. Basic characteristics of patients according to the infertility etiology, PCOS, or unexplained infertility, are shown in Table 2. Clinical pregnancy rates were found to be similar between the urinary and recombinant hCG trigger procedures (p = 0.06). Clinical pregnancy rates per cycle were 22.9% in the PCOS group, and 26.9% in the unexplained group (p = 0.64). The clinical pregnancy rate of the patients who underwent IUI procedures 24 hours and 36 hours following hCG trigger was 39.5% and 17.4%, respectively (p = 0.017; OR = 2.84, 95% CI = 1.18–6.79). When the same analysis was performed separately on the subgroups, PCOS patients, and patients with unexplained infertility, the clinical pregnancy rate when IUI procedures were performed at 24 hours or 36 hours was found to be similar for PCOS patients. However, in the unexplained infertility group, the clinical pregnancy rates were significantly better when the IUI procedure was performed 24 hours following hCG trigger (p = 0.011; OR = 3.73, 95% CI = 1.11–10.60). Clinical pregnancy rates were found to be similar when a receiver operator characteristic (ROC) curve analysis was created according to the cycle day of initiating gonadotropin treatment [area under the curve (AUC) = 0.53; p = 0.61; 95% CI = 0.41–0.65]. Based on another ROC analysis of the whole group, the cycle day of hCG trigger was found to be significantly related to clinical pregnancy rate (AUC = 0.62; p = 0.04; 95% CI = 0.50–0.74; n = 113; Fig. 1). Utilizing a later hCG trigger day appeared to positively affect the odds of clinical pregnancy establishment. An hCG trigger day cut-off value of 11.5 days was detected with sensitivity and specificity values of 65% and 50%, respectively. When a ROC analysis was performed to determine leading follicle diameter and clinical pregnancy rate, no statistically significant relationship was found (AUC = 0.41; p = 0.18; 95% CI = 0.29–0.53). However, a statistically significant relationship was found between high endometrial thickness values on hCG trigger day and clinical pregnancy rate (AUC = 0.66; p = 0.007; 95% CI = 0.55–0.77; Fig. 2). An hCG day endometrial thickness value cut-off value of 9.5 mm was detected with sensitivity and specificity values of 65% and 54%, respectively.