Ultrasound evaluation of the endometrium after medical termination of pregnancy.

Objective: To determine ultrasound parameters associated with the need for clinical intervention after mifepristone and misoprostol termination of pregnancy.

Methods: Charts of patients undergoing medical termination according to a standard protocol in a 13-month period were reviewed. Endometrial thickness and the presence of gestational sac, fluid interface, or complex echoes on postprocedure ultrasonogram were recorded. Repeat doses of medication, surgical intervention, and complications were noted. Success was defined as an abortion completed after a single course of medical therapy.

Results: Postprocedure ultrasonograms were available for 525 of 684 patients. Endometrial thickness was measurable in 437 cases. The observed mean endometrial thickness was 4.10 +/- 1.80 mm (range 0.67-13.4 mm). Endometrial thickness was inversely proportional to the number of days after initiation of therapy when ultrasonography was performed (r = -0.22; P <.001). The endometrium was thicker in the women who had failed than in those who had a successful medical abortion (6.15 +/- 1.95 mm [range 3.35-10.0 mm] versus 4.01 +/- 1.75 mm [range 0.67-13.4 mm], respectively; P <.001), but the wide overlap in endometrial thicknesses nullified the clinical usefulness of this difference.

Conclusion: Endometrial thickness after administration of a single dose of mifepristone and misoprostol for medical termination should not dictate clinical intervention. The decision to treat should be based on the presence of a persistent gestational sac or compelling clinical signs and symptoms.