Association between ectopic pregnancy and pelvic endometriosis

The surgical records of 882 women who had surgery for an ectopic pregnancy (EP) in 5 general hospitals in Vilnius, Lithuania, from 1993 through 1997, were reviewed assessing how many women also had endometriosis. The presence of endometriosis was established according to the American Society for Reproductive Medicine scoring system. The women's mean age was 30.0 years (range, 17–44 years) and mean gravidity and parity were 3.3 (range, 1–13) and 1.0 (range, 0–4). Of the 882 women, 158 underwent laparoscopy for the diagnosis and treatment of EP, 74 underwent diagnostic laparoscopy followed by laparotomy, and the remaining 650 underwent laparotomy only. Endometriosis was diagnosed in only 11 women (1.2%), and it was classified as mild. Operative findings are summarized in Table 1. Seven of the 11 women who had endometriosis were nulliparous, and no endometriosis was found in women younger than 27 years. Reviewing the gynecologic history of all the women revealed that 9 women (1%) had been diagnosed with endometriosis prior to surgery for EP, and lesions were present in 7 at the time of surgery. The other 2 women had had their endometriosis treated, and showed no evidence of endometriosis at the time of surgery for EP. This study supports the scant information available on the near absence of endometriosis in association with EP. In 1988, 2 case-control studies evaluated endometriosis as possible risk factor for EP by investigating the gynecologic history of women with EP, and no relationship was demonstrated [1], [2]. In contrast, a decade later, Coste et al. [3] found that endometriosis was associated with a risk for EP. Recently, Hunter [4], in a hypothetical animal model, suggested that fragments of endometrial tissue may become implanted in the fallopian tube, generating a “uterine-like” environment. Because this study is retrospective, mild endometriosis could have been missed during emergency surgery for a bleeding EP unless it was specifically searched for. Moreover, as most operations were performed by laparotomy, it is likely that mild endometriosis was underdiagnosed due to hemoperitoneum. And yet, despite the lack of a retrospectively matched control group and the reliance on subjective operative reports instead of video records, it is intriguing that the occurrence of endometriosis in Vilnius (1.2%) was almost identical to that observed in Zimbabwe (1.0%) [5] and Norway (2.3%) [6]. In conclusion, this report may describe, for the first time in the English-language medical literature, observations on the prevalence of endometriosis in a selected population from a former Eastern European bloc country. In addition, the extremely low prevalence of endometriosis in this large population-based study seems to question any role of endometriosis in the etiology of EP. Further epidemiological research is needed to definitely determine whether endometriosis is a risk factor for EP.