3. Results
Demographic information was described in Table 1. These 44 patients had received Clomid in 3 sessions (150 mg), and their sonography results did not show any dominant follicle in serial sonography and were known as clomiphene citrate resistant. According to the flow chart (Figure 1), treatment was started. Number of follicles was summarized in Table 2. There was a significant linear relationship between letrozole dosage and follicular number (χ 2 for linear trend: 25.6, P < 0.0001), and this trend was significant in each step (χ 2 for linear trend: 11.48, P = 0.005) (Table 2). Complications were presented in Table 3. There was a significant linear trend between Letrozole dosage and its complications (χ 2 for linear trend: 6.38, P < 0.011) (Table 3). Characteristic of letrozole cycle was showed in Table 4.