Whether and how minimal to mild endometriosis is related to subfertility remains a controversial issue. Retrospective studies have pointed to reduced fecundity in these women compared to those with unexplained infertility. Studies of the effect of removing endometriosis surgically have given conflicting results.
This study was planned to test the hypothesis that, compared to women with no known cause of infertility, those having surgical removal of nonadvanced endometriosis have similar or higher rates of clinical pregnancies (live births) per cycle and cumulative live births following controlled ovarian hyperstimulation (COH) and intrauterine insemination (IUI). The study population included 58 women with endometriosis who were treated during 137 cycles with COH and IUI, and 49 with unexplained infertility who were similarly treated during 122 cycles. Endometriosis was minimal in 41 instances and mild in 17. It had been removed laparoscopically within 7 months before the onset of treatment. COH employed gonadotropin far more often than clomiphene citrate.
The groups with minimal and mild endometriosis and unexplained infertility were similar except for a significantly shorter duration of infertility in the latter group. The pregnancy rate per cycle averaged 20% and was closely similar in women with minimal endometriosis (21%), mild endometriosis (19%), and unexplained infertility (20.5%). The respective cumulative live birth rates within four cycles were 70%, 68%, and 66.5%. Six couples, half of them in the group with minimal endometriosis, had a spontaneous pregnancy during the interval between two treatment cycles. These pregnancies were excluded from life table analysis.
These findings suggest that, when COH and IUI are carried out shortly after laparoscopic removal of minimal or mild endometriosis, pregnancy outcomes are as good as in patients with unexplained subfertility. The investigators believe that COH with IUI is a reasonable first-line treatment for women who have not become pregnant within 6–12 months of having endometriosis excised and who have no other identifiable condition that might compromise fertility.