Miscarriage: diagnosis and management

It is 16:40 in the early pregnancy assessment unit. The sonographer has gone quiet, turned the screen away, and asked you to come in. The woman on the couch is 9 weeks by dates, has had a day of brown spotting, and is still talking about names. In the next five minutes you will make a diagnosis that cannot be unmade, and say something she will repeat to her friends, her GP and possibly a complaints officer. This topic is how to get both right.^[7][15]

Overview and definition

Miscarriage is common: an estimated 23 million occur worldwide each year, with a pooled risk of 15.3% of recognised pregnancies. ^[7][23]

• Gestational limit. C-Gyn 38 (Version 1, March 2025) is a guideline on early pregnancy loss whose management recommendations stop at 14 weeks; recurrent-miscarriage investigation extends to 20 weeks. RCOG Green-top 17 covers recurrent miscarriage including second-trimester losses. Quote the guideline you are using, then say the others differ.^[21][20]
• Where it happens. Most miscarriages — approximately 80% of all cases of pregnancy loss — happen in the first 14 weeks, which is why C-Gyn 38 builds Part 1 around that window.^[21]
• How common. The pooled risk is 15.3% of recognised pregnancies; a Danish lifetime analysis cited in C-Gyn 38 puts ever having one loss at 17.9%, two at 3.9% and three at 0.87% — different measures of different things.^[23][21]

The language rule that now earns marks. C-Gyn 38 asks you to retire three terms: spontaneous abortion, biochemical pregnancy and blighted ovum. They are ambiguous, and the first is actively wounding. Say miscarriage, say early pregnancy loss, and say the baby if she does.^[21]

References21ShowHide

1. [1]Chu JJ, Devall AJ, Beeson LE, et al. Mifepristone and misoprostol versus misoprostol alone for the management of missed miscarriage (MifeMiso): a randomised, double-blind, placebo-controlled trial Lancet, 2020.PMID 32853559
2. [2]Devall A, Chu J, Beeson L, et al. Mifepristone and misoprostol versus placebo and misoprostol for resolution of miscarriage in women diagnosed with missed miscarriage: the MifeMiso RCT Health Technol Assess, 2021.PMID 34821547
3. [3]Schreiber CA, Creinin MD, Atrio J, et al. Mifepristone Pretreatment for the Medical Management of Early Pregnancy Loss N Engl J Med, 2018.PMID 29874535
4. [4]Trinder J, Brocklehurst P, Porter R, et al. Management of miscarriage: expectant, medical, or surgical? Results of randomised controlled trial (miscarriage treatment (MIST) trial) BMJ, 2006.PMID 16707509
5. [5]Preisler J, Kopeika J, Ismail L, et al. Defining safe criteria to diagnose miscarriage: prospective observational multicentre study BMJ, 2015.PMID 26400869
6. [7]Quenby S, Gallos ID, Dhillon-Smith RK, et al. Miscarriage matters: the epidemiological, physical, psychological, and economic costs of early pregnancy loss Lancet, 2021.PMID 33915094
7. [8]Coomarasamy A, Gallos ID, Papadopoulou A, et al. Sporadic miscarriage: evidence to provide effective care Lancet, 2021.PMID 33915095
8. [9]Nanda K, Lopez LM, Grimes DA, et al. Expectant care versus surgical treatment for miscarriage Cochrane Database Syst Rev, 2012.PMID 22419288
9. [10]Lemmers M, Verschoor MA, Kim BV, et al. Medical treatment for early fetal death (less than 24 weeks) Cochrane Database Syst Rev, 2019.PMID 31206170
10. [11]Kim C, Barnard S, Neilson JP, et al. Medical treatments for incomplete miscarriage Cochrane Database Syst Rev, 2017.PMID 28138973
11. [12]Lissauer D, Wilson A, Hewitt CA, et al. A Randomized Trial of Prophylactic Antibiotics for Miscarriage Surgery N Engl J Med, 2019.PMID 30865795
12. [13]Karanth L, Jaafar SH, Kanagasabai S, et al. Anti-D administration after spontaneous miscarriage for preventing Rhesus alloimmunisation Cochrane Database Syst Rev, 2013.PMID 23543581
13. [15]Farren J, Jalmbrant M, Falconieri N, et al. Posttraumatic stress, anxiety and depression following miscarriage and ectopic pregnancy: a multicenter, prospective, cohort study Am J Obstet Gynecol, 2020.PMID 31953115
14. [16]Coomarasamy A, Devall AJ, Cheed V, et al. A Randomized Trial of Progesterone in Women with Bleeding in Early Pregnancy N Engl J Med, 2019.PMID 31067371
15. [17]Devall AJ, Papadopoulou A, Podesek M, et al. Progestogens for preventing miscarriage: a network meta-analysis Cochrane Database Syst Rev, 2021.PMID 33872382
16. [18]Memtsa M, Johns J, Jurkovic D, et al. Diagnosis and outcome of hydatidiform moles in missed-miscarriage: a cohort-study, systematic review and meta-analysis Eur J Obstet Gynecol Reprod Biol, 2020.PMID 32877774
17. [19]Lemmers M, Verschoor MAC, Oude Rengerink K, et al. MisoREST: Surgical versus expectant management in women with an incomplete evacuation of the uterus after misoprostol treatment for miscarriage: A cohort study Eur J Obstet Gynecol Reprod Biol, 2017.PMID 28209537
18. [20]Regan L, Rai R, Saravelos S, Li TC; Royal College of Obstetricians and Gynaecologists Recurrent MiscarriageGreen-top Guideline No. 17 BJOG, 2023.PMID 37334488
19. [21]Royal Australian and New Zealand College of Obstetricians and Gynaecologists Miscarriage, Recurrent Miscarriage and Ectopic Pregnancy (C-Gyn 38) RANZCOG Clinical Guideline, 2025.Source
20. [22]National Institute for Health and Care Excellence Ectopic pregnancy and miscarriage: diagnosis and initial management NICE guideline NG126, 2026.Source
21. [23]Duane M, Schliep K, Porucznik CA, et al. Does a short luteal phase correlate with an increased risk of miscarriage? A cohort study BMC Pregnancy Childbirth, 2022.PMID 36482355