By Rebecca H. Allen, MD, MPH, Editor
SYNOPSIS: In this randomized controlled trial of 563 women comparing vacuum aspiration and operative hysteroscopy for incomplete spontaneous abortion, there was no difference in pregnancy rates within the following two years (62.8% hysteroscopy vs. 67.6% vacuum aspiration; risk difference, -4.8%; 95% confidence interval, -13% to 3%).
SOURCE: Huchon C, Drioueche H, Koskas M, et al. Operative hysteroscopy vs vacuum aspiration for incomplete spontaneous abortion: A randomized clinical trial. JAMA 2023;329:1197-1205.
There has been interest by minimally invasive gynecologic surgeons in using operative hysteroscopy for the treatment of retained products of conception (POC). The rationale behind this is the thought that directed hysteroscopic removal of POC would reduce intrauterine adhesion formation compared to vacuum aspiration and, thus, improve future fertility. This has been controversial; therefore, the authors of this study sought to compare the two techniques in a randomized fashion.
The authors conducted a single-blind randomized trial at 15 centers in France. Inclusion criteria included age 18 to 44 years with incomplete spontaneous abortion less than 14 weeks’ gestation that was a located pregnancy with retained POC diagnosed by transvaginal ultrasound showing a heterogenous mass or intrauterine sac more than 15 mm thick with or without embryo and desiring a future pregnancy as soon as possible after the procedure.
Exclusion criteria were known uterine malformation, previous surgical treatment of the current pregnancy, need for emergency surgical evacuation to treat hemorrhage, presence of an intrauterine device, intrauterine material > 50 mm thick on ultrasound, or pregnancy from in vitro fertilization.
The intervention group received operative hysteroscopy, and the retained POC were resected completely with a bipolar resection system without electricity. The control group received a standard vacuum electric aspiration. The primary outcome was the occurrence of an intrauterine pregnancy lasting beyond 22 weeks’ gestation in the two years after the procedure. Secondary outcomes were time to conception, surgical reintervention, and any subsequent spontaneous abortion or ectopic pregnancy in the two-year period. Adverse events and complications also were tracked. The subjects were seen three to eight weeks postoperatively and then contacted by telephone at six, 12, and 24 months.
A total of 563 patients were recruited, with 281 in the vacuum aspiration arm and 282 in the hysteroscopic arm. In the vacuum aspiration group, all patients received the planned procedure. In the hysteroscopic group, four patients inadvertently received vacuum aspiration, 18 patients had to be converted to vacuum aspiration, and one patient procedure failed.
Intraoperative ultrasound guidance was used for 54.1% of the hysteroscopy group and 83.6% of the vacuum group. About three-quarters of the participants had missed abortions (embryonic demise or anembryonic pregnancy) and one-quarter had retained POC. The length of surgery was longer in the hysteroscopic group (median 30 minutes vs. 11.5 minutes, P < 0.001). In the intention-to-treat analysis, there was no difference between the two groups in terms of pregnancy rates lasting beyond 22 weeks, with 62.8% in the hysteroscopy group and 67.6% in the vacuum aspiration group (risk difference, -4.8%; 95% confidence interval, -13% to 3%). There was a similar result in the per-protocol analysis. The rates of complication were no different between the two groups, with four uterine perforations and two hemorrhages ≥ 500 mL in the hysteroscopy group and one and three, respectively, in the vacuum aspiration group. There was no difference in the time to conception between the two groups.
COMMENTARY
This randomized controlled trial showed that there was no advantage to operative hysteroscopy for the management of missed abortion and spontaneous incomplete abortion. Furthermore, not all procedures could be completed hysteroscopically and the surgeries took longer and used more resources. The title of the study implied to me that the study was about solely retained POC; however, after reading the methods, it was clear that missed abortions also were included, which is not the typical population where hysteroscopic resection is used, in my experience.
Although one-quarter of the subjects did have retained POC, the power of the study to evaluate this specific sub-population may be limited. The strength of the study was the randomized design and large number of subjects. Additionally, the primary outcome (pregnancy > 22 weeks’ gestation) was clinically relevant to providers and patients.
It is true that previous studies have shown some advantage to hysteroscopic resection of prolonged retained POC after initial management in terms of reducing intrauterine adhesion formation and improving subsequent pregnancy rates.1 This was not the population included in the present study, however. The initial management of missed abortion and incomplete abortion, in hemodynamically stable patients, includes expectant management, surgical management with vacuum aspiration, and medical management with mifepristone and misoprostol or misoprostol alone.2
The success rates of these approaches vary according to the type of abortion (missed or incomplete). Surgical evacuation typically is 98% successful for missed or incomplete abortion and vacuum aspiration procedures can be performed safely in the office setting. However, surgery is not always needed or desired; therefore, patients are offered medical and expectant management as well, if appropriate. Mifepristone has been shown to increase the success of uterine evacuation when combined with misoprostol for missed abortion and commonly is used off-label for this purpose. It is hoped that mifepristone will continue to be available on the market.
This study will not change my clinical management, since we never used operative hysteroscopy for the initial management of missed or spontaneous incomplete abortion. However, it is helpful that this study has shown that a more expensive and complicated intervention is not necessary.
REFERENCES
- Vitale SG, Parry JP, Carugno J, et al. Surgical and reproductive outcomes after hysteroscopic removal of retained products of conception: A systematic review and meta-analysis. J Minim Invasive Gynecol 2021;28:204-217.
- The American College of Obstetricians and Gynecologists. Early Pregnancy Loss. Practice Bulletin Number 200. Published November 2018. https://www.acog.org/clinical/clinical-guidance/practice-bulletin/articles/2018/11/early-pregnancy-loss
