Eleven studies (n=313 women in repetitive surgery arm, range 9 to 89) were included in the review. Six studies were classed as non-comparative (n=139 women), and five studies as comparative (n=174 women). Where reported, length of follow-up ranged from nine to 60 months.
Comparison between repeat and primary surgery: Within three studies (n=701 women), the pooled pregnancy rates at end of follow-up were 41% (95% CI 37 to 45) for the primary surgery group and 23% (95% CI 16 to 31) for the repetitive surgery group. The pooled odds ratio of pregnancy rates comparing repetitive and primary surgery groups was 0.44 (95% CI 0.28 to 0.68) in favour of primary surgery groups (n=236 out of 577 women in the primary surgery group; n=28 out of 124 women in the repetitive surgery group).
Comparison between second-line surgery and IVF embryo transfer: The pooled results of two studies (n=97 women) reported no statistically significant difference between the two treatments.
Comparison between laparotomy and laparoscopy: The mean weighted conception rate at end of follow-up was 27% (95% CI 20 to 35) with laparotomy, and 25% (95% CI 18 to 33) with laparoscopy, indicating no significant differences between the two treatment approaches.
Heterogeneity was assessed as insignificant within both comparative and non-comparative studies.