The predictive value of endometrial stripe thickness in patients with suspected ectopic pregnancy who have an empty uterus at ultrasonography

UNLABELLED: Prior research suggests that, in patients with empty uteri at ultrasonography, endometrial stripe thickness may be predictive of ectopic pregnancy or the likelihood of obtaining chorionic villi after a dilatation and evacuation procedure (D+E). However, it is unclear whether the predictive value of endometrial stripe thickness is confined to patients with low beta-human chorionic gonadotropin (beta-hCG) values.

OBJECTIVE: To determine whether endometrial stripe thickness is predictive of the risk of ectopic pregnancy or the likelihood of obtaining chorionic villi after D+E in patients with beta-hCG values >1,000 mIU/mL or < or =1,000 mIU/mL.

METHODS: In an urban academic ED, the authors conducted a retrospective chart review of consecutive ED patients from August 1991 to August 1997 with abdominal pain or vaginal bleeding, a positive beta-hCG value, and an empty uterus by transvaginal ultrasound examination. Patients were divided into four groups-group 1: endometrium thin, beta-hCG value < or =1,000 mIU/mL; group 2: endometrium thick, beta-hCG value < or =1,000 mIU/mL; group 3: endometrium thin, beta-hCG value >1,000 mIU/ mL; and group 4: endometrium thick, beta-hCG value >1,000 mIU/mL. The secondary analysis was limited to patients who had a D+E performed within 48 hours of the ED visit. The risks of ectopic pregnancy and the likelihoods of obtaining chorionic villi after D+E were compared using chi-square or Fishers' exact test where appropriate, with a p-value of 0.05 being significant.

RESULTS: 224 patients were enrolled in the initial analysis. Intergroup differences in the frequency of ectopic pregnancy were of borderline significance (p = 0.08). However, when the comparison was limited to the groups with beta-hCG values < or =1,000 mIU/mL, the predictive value of endometrial stripe thickness reached statistical significance (group 1: 27/99 [27%], group 2: 2/28 [7%], p = 0.05). 79 patients had a D+E performed. Intergroup differences in the rate of obtaining chorionic villi were significant (p = 0.002). Group 1 had the lowest frequency of having chorionic villi identified (4/26 [15%]) and was the only group in which villi were obtained in fewer than 50% of cases.

CONCLUSION: Endometrial stripe thickness may be predictive of the risk of ectopic pregnancy and the likelihood of obtaining chorionic villi at D+E. However, its predictive value appears to be confined to patients with beta-hCG values < or =1,000 mIU/mL.