Statistical Analysis
All data were analyzed by IBM SPSS Version 21.0 (IBM, Armonk, NY, USA), and the survival package in R was used for drawing plots of survival analysis. Continuous variables were compared using Student t-test and Mann-Whitney’s U test for normally and non-normally distributed data, respectively. Categorical variables were analyzed using the Pearson chi-squared (χ2) or Fisher exact probability test. The Kaplan-Meier method was used to compute cumulative livebirth rate curves (1-survival function) between the two groups, and the differences were compared using a log-rank test. The date of entry for each patient was the date of surgery. The last day of analysis was the date of the first delivery or the last follow-up visit in women who remained non-livebirth. Women who had no event at the end of the analysis were recorded censoring data. We processed a Cox proportional hazards regression model with potential variables in an enter fashion to identify predictors of successful live birth. The magnitude of statistical significance was expressed with adjusted hazard ratios (AHR) and 95% confidence intervals (CI). Two-tailed P-values < 0.05 were considered statistically significant.
Initial analysis was by intention-to-treat (ITT). We also performed a per-protocol (PP) analysis in which we ruled out 8 patients who had additional bilateral salpingectomy for recurrent hydrosalpinges or for EP.