Does gestational sac volume predict the outcome of missed miscarriage managed expectantly?

The aim of this study was to investigate whether gestational sac volume (GSV) can predict the outcome of missed miscarriages that are managed expectantly.

This was a prospective observational study. Between February 1, 2000, and January 31, 2001, all patients with a confirmed first-trimester missed miscarriage who chose to undergo expectant management were recruited to participate. A single investigator performed all sonographic examinations and measurements. The main outcome measure was a complete spontaneous abortion within 4 weeks of the initial diagnosis. A complete miscarriage was defined as a maximum anteroposterior diameter of the endometrium of less than 15 mm on transvaginal sonography and no persistent heavy vaginal bleeding. The patients could opt to undergo surgery at any time, but those who had not expelled the products of conception within 4 weeks of the diagnosis were advised to have surgical uterine evacuation.

In total, 90 patients were enrolled, and 86 patients completed the study. The mean GSV, as measured by 3-dimensional sonography, was 9.7 +/- 8.9 ml, and the mean sac diameter was 24.5 +/- 8.0 mm. A significant exponential correlation was found between the mean sac diameter and the GSV (r = 0.86; p < 0.0001). Forty-six (53.5%) of the 86 patients experienced a complete miscarriage within 4 weeks of the diagnosis (ie, expectant management was successful), but expectant management was unsuccessful in the remaining 40 (46.5%) patients (5 had an incomplete miscarriage, and 35 did not expel the products of conception). The GSV did not differ significantly between the "successful" and "unsuccessful" groups (p = 0.82). A logistic regression analysis showed no significant correlation between GSV and the outcome of missed miscarriages managed expectantly (p = 0.59).

The GSV does not predict the outcome of expectant management of missed miscarriage within 4 weeks of the diagnosis.