Expectant management of spontaneous first-trimester miscarriage: prospective validation of the '2-week rule'

To assess uptake and success of expectant management of first-trimester miscarriage for a finite 14-day period, in order to evaluate our '2-week rule' of management.

This was a prospective observational study evaluating our proposed 2-week rule of expectant management, which is based on the finding that women managed expectantly are most likely to miscarry in the first 14 days and that to wait longer than 2 weeks without intervention does not confer a greater chance of successful resolution. Eligible women diagnosed with first-trimester miscarriage were offered a choice of expectant management or surgical evacuation under general anesthesia. Inclusion criteria for expectant management were: diagnosis of incomplete miscarriage (heterogeneous tissue, with or without a gestational sac, seen on ultrasound in the uterine cavity and distorting the endometrial midline echo), missed miscarriage (crown-rump length (CRL) >or= 6 mm with absent fetal heart activity) or empty sac (anembryonic pregnancy) based on transvaginal ultrasonography. Women with complete miscarriage, missed miscarriage at the nuchal translucency scan, molar pregnancy or miscarriage >or= 3 weeks in duration (missed miscarriage in which the CRL was >or= 3 weeks smaller than the gestational age based on last menstrual period), or with signs of infection or hemodynamic instability were excluded. Expectant management consisted of weekly ultrasonography for 2 weeks. If after 2 weeks resolution was not complete, surgery was advised.

1062 consecutive pregnant women underwent transvaginal ultrasound examination. Of these, 38.6% (410/1062) were diagnosed with miscarriage, of whom 241 (59%) were symptomatic at the time of presentation and 282 were eligible for the study. These were offered expectant management and 80% (227/282) took up this option. 11% (24/227) were lost to follow-up; therefore, complete data were available on 203 women. Overall spontaneous resolution of miscarriage at 2 weeks was observed in 61% (124/203) of women. Rates of spontaneous resolution at 2 weeks according to the type of miscarriage were 71% for incomplete miscarriage, 53% for empty sac and 35% for missed miscarriage. The incidence of unplanned emergency dilatation and curettage due to gynecological infection or hemorrhage was 2.5% (5/203).

Expectant management based on the 2-week rule is a viable and safe option for women with first-trimester miscarriage. Women with an incomplete miscarriage are apparently the most suitable for expectant management.