At least 15 percent of clinically recognized pregnancies result in miscarriage during the first trimester, and many are routinely treated by surgical evacuation of the uterus. This surgery can have serious complications, including infection, perforation of the uterus, and damage to the bowel. Luise and colleagues investigated the acceptability and outcome of monitoring without surgical intervention in cases of spontaneous first-trimester miscarriage.

They studied 1,096 consecutive women attending a special early pregnancy assessment unit of a London teaching hospital because of suspected miscarriage during the first trimester. After assessment and ultrasonography, each miscarriage was classified as complete, incomplete, missed, or anembryonic, based on the guidelines of the Royal College of Obstetricians and Gynecologists. Women with complete miscarriage were discharged with arrangements to follow up and promptly report any further signs or symptoms. The 686 women with retained products of conception were given the choice of surgical evacuation of the uterus or expectant management. The women who chose expectant management had the option to request surgical evacuation at any time. Otherwise, progress was monitored by weekly ultrasonography for up to four weeks. Symptoms were monitored throughout the study, and completion of the miscarriage was assessed by cessation of vaginal bleeding and an endometrial thickness of less than 15 mm on ultrasound.

Two patients with molar pregnancies were excluded, and 408 patients were classified as having completed the miscarriage at the initial assessment. Of the 686 remaining women, 478 (70 percent) opted for expectant management. Complete data were available on 451 of these women. Overall, 201 of the 221 (91 percent) incomplete miscarriages spontaneously completed with expectant management. The rate of spontaneous completion for missed miscarriage was 105 of 138 (76 percent), and for anembryonic pregnancies it was 61 of 92 (66 percent). In the whole group, complications were documented in 11 women (1 percent), and five of these were related to surgical evacuation of the uterus. Only six (1 percent) of the 451 women treated expectantly had any complications.

The authors concluded that most women would choose expectant management of early miscarriage if they were assured of close monitoring and the availability of surgery if required or requested. They attribute much of this attitude to the extent and quality of patient support and counseling.