First dose of misoprostol administration at home or in hospital for medical abortion between 12-22 gestational weeks in Sweden (PRIMA): a multicentre, open-label, randomised controlled trial

Abstract

Background: Medical abortion after 12 gestational weeks often requires a stay in hospital. We hypothesised that administering the first misoprostol dose at home could increase day-care procedures as compared with overnight care procedures, shorten inpatient stays, and improve patient satisfaction.

Methods: This multicentre, open-label, randomised controlled trial was done at six hospitals in Sweden. Participants were pregnant people aged 18 years and older who were undergoing medical abortion at 85-153 days of pregnancy. Randomisation was done in blocks 1:1 to mifepristone administered in-clinic followed by home administration or hospital administration of the first dose of misoprostol. Allocation was done by opening of opaque allocation envelopes. Due to the nature of the intervention, masking was not feasible. Between 24-48 h after mifepristone 200 mg, the participants administered 800 μg of misoprostol either at home 2 h before admission to hospital or in hospital. The primary outcome was the proportion of day-care procedures (defined as abortion completed in <9 h). The intention-to-treat analysis included all participants randomly assigned to receive the study drug and who had known results for the primary outcome. Individuals who received any treatment were included in the safety analyses. This trial is registered at ClinicalTrials.gov, NTC03600857, and EudraCT, 2018-000964-27.

Findings: Between Jan 8, 2019, and Dec 21, 2022, 457 participants were randomly assigned to treatment groups. In the intention-to-treat-population, 220 participants were assigned to the home group and 215 to the hospital group. In the home group, 156 (71%) of 220 participants completed the abortion as day-care patients, compared with 99 (46%) of 215 in the hospital group (difference 24·9%, 95% CI 15·4-34·3; p<0·0001). In total, 97 (22%) of 444 participants in the safety analysis had an adverse event. Seven (2%) of 444 participants aborted after mifepristone only. Two (1%) of 220 in the home group aborted after the first dose of misoprostol, before hospital admission.

Interpretation: Home administration of misoprostol significantly increases the proportion of day-care procedures in medical abortion after 12 gestational weeks, offering a safe and effective alternative to in-clinic protocols.

Funding: Region Västra Götaland, Hjalmar Svensson's Fund, the Gothenburg Society of Medicine, Karolinska Institutet-Region Stockholm, and The Swedish Research Council.