Miscarriage is the most common complication of pregnancy. As many as 15-25% of pregnancies end in miscarriage, and the number of miscarriages in England is estimated to be approximately 125,000 per year. Miscarriage often brings not only physical pain, bleeding and risks of infection, but also psychological impacts on women and their families. This study will focus on women whose pregnancy sac remains inside the womb (known as a missed miscarriage) and opt for medical management of their miscarriage up to 13+6 weeks of pregnancy. NICE currently recommends that a drug called misoprostol (a vaginal pessary or oral tablet that makes the womb contract) should be used in the medical treatment of miscarriage. However, there is evidence to suggest that combining this drug with mifepristone (an oral tablet that reduces pregnancy hormones) may be more effective in treating miscarriage. Therefore, to test this in a clinical trial, participants will be allocated at random to receive either mifepristone followed by misoprostol, or a dummy drug (placebo) followed by misoprostol. Neither the participants nor the researchers will know what allocation is decided, which is necessary to test the treatments fairly. The main outcome of interest will be whether miscarriage is complete within 7 days of randomisation. If miscarriage is not complete then further treatment (more tablets or surgery) will be offered. A number of other key outcomes, such as the need for an operation, will also be assessed. We will also study the views and experience of the participants regarding the tablet treatment.

We anticipate that 710 women will be required to take part in the study to answer this question with confidence. We estimate that we would be able to recruit this many women in two years.

Aim: To investigate the clinical and cost-effectiveness of MifeMiso combination (mifepristone and misoprostol) versus misoprostol alone in the management of missed miscarriage.

Primary clinical objective: To test the hypothesis that treatment with mifepristone plus misoprostol is superior to misoprostol alone for the resolution of miscarriage within 7 days in women diagnosed with missed miscarriage by pelvic ultrasound scan in the first 13+6 weeks of pregnancy.

Key secondary objective:To test the hypothesis that the addition of mifepristone reduces the need for surgical intervention to resolve the miscarriage.

Other secondary objectives:

1. To evaluate if the addition of mifepristone reduces the need for further doses of misoprostol.
2. To evaluate if the addition of mifepristone improves other clinical outcomes including surgical intervention up to and including 7 days post-randomisation and after 7 days post-randomisation, duration of bleeding, infection, negative pregnancy test at 21 days post-randomisation, time from randomisation to discharge from EPU care, side effects and complications.
3. To evaluate if the addition of mifepristone improves patient satisfaction
4. To assess the cost-effectiveness of the combination of mifepristone and misoprostol in the medical management of missed miscarriage.

Economic objectives: To assess the cost-effectiveness of the combination of mifepristone and misoprostol in the medical management of missed miscarriage based on an outcome of additional cost per additional successfully managed miscarriage and additional cost per additional quality-adjusted life-year (QALY). Using a model-based economic evaluation we will further explore the cost-effectiveness of the medical management of missed miscarriage, as explored in the proposed trial, with alternative management strategies, such as surgical and expectant, based on available secondary sources.

Mixed-method evaluation objectives: To explore the satisfaction of patients who complete the trial protocol. The results of the satisfaction survey (CSQ-8) will act as a sampling frame to conduct semi-structured interviews to further investigate patient experiences and satisfaction with medical management of missed miscarriage.

Inclusion Criteria:

• Women diagnosed with missed miscarriage by pelvic ultrasound scan in the first 13+6 weeks of pregnancy that choose to have medical management of miscarriage.
• Age 16 years and over
• Willing and able to give informed consent.

Exclusion Criteria:

• Women opting for alternative methods of miscarriage management (expectant or surgical)
• Diagnosis of incomplete miscarriage.
• Life threatening bleeding.
• Contraindications to mifepristone or misoprostol use for example chronic adrenal failure, known hypersensitivity to either drug, haemorrhagic disorders and anticoagulant therapy, prosthetic heart valve or history of endocarditis, existing cardiovascular disease, severe asthma uncontrolled by therapy or inherited porphyria.
• Participation in any other blinded, placebo-controlled trials of investigational medicinal products in pregnancy.
• Previous participation in the MifeMiso trial
• Woman not able to attend for day 6-7 ultrasound scan

Participants, investigators, research midwives/nurses and other attending clinicians will remain blind to the trial drug allocation throughout the duration of the trial.