Miscarriage

Overview 
Theory 
Diagnosis 
Management 
Follow up 
Resources 

Last reviewed: 5 Aug 2025

Last updated: 03 Feb 2023

Miscarriage occurs in up to one third of pregnancies.

Described as threatened, inevitable, incomplete, complete, missed, or recurrent miscarriage.

Presence of pain, hypotension, tachycardia, and/or anemia warrants exclusion of a life-threatening differential diagnosis such as an ectopic pregnancy.

Serial serum beta hCG titers and a transvaginal ultrasound scan aid in diagnosis.

Medical or surgical uterine evacuation is recommended when the pregnancy is no longer viable. The patient may also be offered a choice of conservative management unless there is profuse, heavy, and persistent bleeding.

The experience of a miscarriage is associated with a psychological impact of varying intensity in the short or long term, or both.

Definition

Miscarriage is an involuntary, spontaneous loss of a pregnancy before 20-24 completed weeks.[1] The gestational threshold for the definition varies between countries: in the US it is usually 20 weeks (but may vary in different states), whereas in the UK, the Royal College of Obstetricians and Gynaecologists defines it as 24 weeks.[2][3] After these differing cut-offs, the loss would be defined as a stillbirth. Miscarriage is associated with unprovoked vaginal bleeding with or without suprapubic pain. The commonly used term, abortion, is unpopular with women who are uncomfortable with a suggestion that it follows an intentional attempt to terminate the pregnancy.[4]

History and exam

Key diagnostic factors

vaginal bleeding with or without clots

Full details

Other diagnostic factors

suprapubic pain
low back pain
recent postcoital bleed
uterine structural abnormality
history of trauma

Full details

Risk factors

older age
uterine malformation
bacterial vaginosis
thrombophilia
parental chromosomal anomaly
vitamin D deficiency
previous spontaneous/induced miscarriage
infertility/assisted conception
nonsteroidal anti-inflammatory drugs (NSAIDs)
caffeine
alcohol
smoking
overweight/obesity
thyroid dysfunction
diabetes mellitus

Full details

Diagnostic tests

1st tests to order

transvaginal ultrasound scan
serum beta hCG titers

Full details

Tests to avoid

inherited thrombophilia test

Full details

Tests to consider

transabdominal ultrasound scan
serum progesterone
urine pregnancy test
CBC
rhesus blood group
lupus anticoagulant, anticardiolipin antibodies, and anti-beta 2 glycoprotein I antibodies
pelvic ultrasound
cytogenetic analysis on products of conception
parental karyotype
vaginal swab

Full details

Treatment algorithm

INITIAL

threatened miscarriage

ACUTE

inevitable/incomplete/missed miscarriage

complete miscarriage

ONGOING

recurrent miscarriage

Contributors

Authors

Ida Muslim, MBChB, MRCOG

Consultant Obstetrician & Gynaecologist

The Women’s Centre

Gloucestershire Royal Hospital

Gloucester

Disclosures

IM declares that she has no competing interests.

Jothi Doraiswamy, MBBS, MRCOG

Consultant in Obstetrics and Gynaecology

Gloucestershire Royal Hospital

Gloucester

Disclosures

JD declares that she has no competing interests.

Acknowledgements

Dr Ida Muslim and Dr Jothi Doraiswamy would like to gratefully acknowledge Dr Isaac Babarinsa and Professor Tim Draycott, previous contributors to this topic.

Disclosures

IB and TD declare that they have no competing interests.

Peer reviewers

Jo Trinder, MD

Consultant Obstetrician and Gynaecologist

St Michael's Maternity Wing

Bristol Royal Infirmary

Bristol

Disclosures

JT is the primary author of one randomized controlled trial cited in this topic. This trial was funded by an NHS Research and Development Grant and a donation from Exelgyn, the manufacturer of misoprostol. JT has accepted honoraria for speaking to groups of midwives and doctors about miscarriage management.

John Bachman, MD

Consultant in Family Medicine

Parker D Sanders and Isabella Sanders Professor of Primary Care

Rochester

Disclosures

JB declares that he has no competing interests.

Peer reviewer acknowledgements

BMJ Best Practice topics are updated on a rolling basis in line with developments in evidence and guidance. The peer reviewers listed here have reviewed the content at least once during the history of the topic.

Disclosures

Peer reviewer affiliations and disclosures pertain to the time of the review.

References

Our in-house evidence and editorial teams collaborate with international expert contributors and peer reviewers to ensure that we provide access to the most clinically relevant information possible.

Key articles

World Health Organization, UNICEF, United Nations Population Fund. Vaginal bleeding in early pregnancy. In: Managing complications in pregnancy and childbirth: a guide for midwives and doctors - 2nd edition. 2017 [internet publication].Full text

National Institute for Health and Care Excellence. Ectopic pregnancy and miscarriage: diagnosis and initial management. Nov 2021 [internet publication].Full text

European Society of Human Reproduction and Embryology. Guideline on the management of recurrent pregnancy loss. Nov 2017 [internet publication].Full text

American College of Obstetricians and Gynecologists. Practice bulletin: early pregnancy loss. Nov 2018 [internet publication].Full text

Kim C, Barnard S, Neilson JP, et al. Medical treatments for incomplete miscarriage. Cochrane Database Syst Rev. 2017 Jan 31;(1):CD007223.Full text Abstract

Tunçalp O, Gülmezoglu AM, Souza JP. Surgical procedures for evacuating incomplete miscarriage. Cochrane Database Syst Rev. 2010 Sep 8;(9):CD001993.Full text Abstract

Duckitt K, Qureshi A. Recurrent miscarriage. BMJ Clin Evid. 2015 [internet publication].

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.

Differentials
- Ectopic pregnancy/heterotopic pregnancy
- Hydatidiform mole
- Partial hydatidiform mole
More Differentials
Guidelines
- Ectopic pregnancy and miscarriage: diagnosis and initial management
- ACR appropriateness criteria: abnormal uterine bleeding
More Guidelines
Patient information
Miscarriage
More Patient information
Videos
Miscarriage: experience of miscarriage
Miscarriage: discussing causal factors
More videos
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Miscarriage

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic tests

1st tests to order

Tests to avoid

Tests to consider

Treatment algorithm

threatened miscarriage

inevitable/incomplete/missed miscarriage

complete miscarriage

recurrent miscarriage

Contributors

Authors

Ida Muslim, MBChB, MRCOG

Disclosures

Jothi Doraiswamy, MBBS, MRCOG

Disclosures

Acknowledgements

Disclosures

Peer reviewers

Jo Trinder, MD

Disclosures

John Bachman, MD

Disclosures

Peer reviewer acknowledgements

Disclosures

References

Key articles

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.

Differentials

Guidelines

Patient information

Videos

Log in or subscribe to access all of BMJ Best Practice

Log in or subscribe to access all of BMJ Best Practice

Log in to access all of BMJ Best Practice