Background In most pregnancies that miscarry, arrest of embryonic or fetal development occurs some time (often weeks) before the miscarriage occurs. Ultrasound examination can reveal abnormal findings during this phase by demonstrating anembryonic pregnancies or embryonic or fetal death. Treatment has traditionally been surgical but medical treatments may be effective, safe, and acceptable, as may be waiting for spontaneous miscarriage. This is an update of a review first published in 2006. Objectives To assess, from clinical trials, the effectiveness and safety of different medical treatments for the termination of non-viable pregnancies. Search methods For this update, we searched Cochrane Pregnancy and Childbirth’s Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (24 October 2018) and reference lists of retrieved studies. Selection criteria Randomised trials comparing medical treatment with another treatment (e.g. surgical evacuation), or placebo, or no treatment for early pregnancy failure. Quasi-randomised studies were excluded. Cluster-randomised trials were eligible for inclusion, as were studies reported in abstract form, if sufficient information was available to assess eligibility. Data collection and analysis Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. We assessed the quality of the evidence using the GRADE approach. Main results Forty-three studies (4966 women) were included. The main interventions examined were vaginal, sublingual, oral and buccal misoprostol, mifepristone and vaginal gemeprost. These were compared with surgical management, expectant management, placebo, or different types of medical interventions were compared with each other. The review includes a wide variety of different interventions which have been analysed across 23 different comparisons. Many of the comparisons consist of single studies. We limited the grading of the quality of evidence to two main comparisons: vaginal misoprostol versus placebo and vaginal misoprostol versus surgical evacuation of the uterus. Risk of bias varied widely among the included trials. The quality of the evidence varied between the different comparisons, but was mainly found to be very-low or low quality. Vaginal misoprostol versus placebo Vaginal misoprostol may hasten miscarriage when compared with placebo: e.g. complete miscarriage (5 trials, 305 women, risk ratio (RR) 4.23, 95% confidence interval (CI) 3.01 to 5.94; low-quality evidence). No trial reported on pelvic infection rate for this comparison. Vaginal misoprostol made little difference to rates of nausea (2 trials, 88 women, RR 1.38, 95% CI 0.43 to 4.40; low-quality evidence), diarrhoea (2 trials, 88 women, RR 2.21, 95% CI 0.35 to 14.06; low-quality evidence) or to whether women were satisfied with the acceptability of the method (1 trial, 32 women, RR 1.17, 95% CI 0.83 to 1.64; low-quality evidence). It is uncertain whether vaginal misoprostol reduces blood loss (haemoglobin difference > 10 g/L) (1 trial, 50 women, RR 1.25, 95% CI 0.38 to 4.12; very-low quality) or pain (opiate use) (1 trial, 84 women, RR 5.00, 95% CI 0.25 to 101.11; very-low quality), because the quality of the evidence for these outcomes was found to be very low. Vaginal misoprostol versus surgical evacuation Vaginal misoprostol may be less effective in accomplishing a complete miscarriage compared to surgical management (6 trials, 943 women, average RR 0.40, 95% CI 0.32 to 0.50; Heterogeneity: Tau² = 0.03, I² = 46%; low-quality evidence) and may be associated with more nausea (1 trial, 154 women, RR 21.85, 95% CI 1.31 to 364.37; low-quality evidence) and diarrhoea (1 trial, 154 women, RR 40.85, 95% CI 2.52 to 662.57; low-quality evidence). There may be little or no difference between vaginal misoprostol and surgical evacuation for pelvic infection (1 trial, 618 women, RR 0.73, 95% CI 0.39 to 1.37; low-quality evidence), blood loss (post-treatment haematocrit (%) (1 trial, 50 women, mean difference (MD) 1.40%, 95% CI-3.51 to 0.71; low-quality evidence), pain relief (1 trial, 154 women, RR 1.42, 95% CI 0.82 to 2.46; low-quality evidence) or women’s satisfaction/acceptability of method (1 trial, 45 women, RR 0.67, 95% CI 0.40 to 1.11; low-quality evidence). Other comparisons Based on findings from a single trial, vaginal misoprostol was more effective at accomplishing complete miscarriage than expectant management (614 women, RR 1.25, 95% CI 1.09 to 1.45). There was little difference between vaginal misoprostol and sublingual misoprostol (5 trials, 513 women, average RR 0.84, 95% CI 0.61 to 1.16; Heterogeneity: Tau² = 0.10, I² = 871%; or between oral and vaginal misoprostol in terms of complete miscarriage at less than 13 weeks (4 trials, 418 women), average RR 0.68, 95% CI 0.45 to 1.03; Heterogeneity: Tau² = 0.13, I² = 90%). However, there was less abdominal pain with vaginal misoprostol in comparison to sublingual (3 trials, 392 women, RR 0.58, 95% CI 0.46 to 0.74). A single study (46 women) found mifepristone to be more effective than placebo: miscarriage complete by day five after treatment (46 women, RR 9.50, 95% CI 2.49 to 36.19). However the quality of this evidence is very low: there is a very serious risk of bias with signs of incomplete data and no proper intention-to-treat analysis in the included study; and serious imprecision with wide confidence intervals. Mifepristone did not appear to further hasten miscarriage when added to a misoprostol regimen (3 trials, 447 women, RR 1.18, 95% CI 0.95 to 1.47). Authors’ conclusions Available evidence from randomised trials suggests that medical treatment with vaginal misoprostol may be an acceptable alternative to surgical evacuation or expectant management. In general, side effects of medical treatment were minor, consisting mainly of nausea and diarrhoea. There were no major differences in effectiveness between different routes of administration. Treatment satisfaction was addressed in only a few studies, in which the majority of women were satisfied with the received intervention. Since the quality of evidence is low or very low for several comparisons, mainly because they included only one or two (small) trials; further research is necessary to assess the effectiveness, safety and side effects, optimal route of administration and dose of different medical treatments for early fetal death.