Molar pregnancies

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

Last reviewed: 4 Apr 2025

Last updated: 18 Jan 2024

Molar pregnancies (MPs; hydatidiform moles) are chromosomally abnormal pregnancies that have the potential to become malignant.

There is a higher possibility of MP in women less than 20 years of age or over 35 years of age, and in those who have experienced MP in a previous pregnancy.

The most common presenting symptom is vaginal bleeding.

Suction evacuation (electrical or manual) is the preferred management option in women who desire preservation of fertility.

Hysterectomy may be considered in women who do not want to preserve fertility.

The risk of postmolar neoplasm is 15% to 20% for those with complete hydatidiform mole and 1% to 5% for those with partial hydatidiform mole.

Over 95% of women with postmolar gestational trophoblastic neoplasia attain remission, often with preservation of fertility.

Definition

Molar pregnancies (hydatidiform moles) are chromosomally abnormal pregnancies that have the potential to become malignant (gestational trophoblastic neoplasia). If a MP or other conception gives rise to a persistent locally invasive and/or metastatic trophoblastic tumor, this is considered to be gestational trophoblastic neoplasia (GTN). Gestational trophoblastic disease includes tumors, such as hydatidiform moles and GTN, arising from placental trophoblasts. Syncytiotrophoblasts secrete human chorionic gonadotropin and, therefore, this hormonal product is used as a tumor marker for the disease.[1][2][3]

History and exam

Key diagnostic factors

first trimester of pregnancy
vaginal bleeding
unusual uterine size for gestational age

Full details

Other diagnostic factors

early-onset preeclampsia
shortness of breath and respiratory distress
severe nausea and emesis
tachycardia, tremor, insomnia, and diarrhea
pallor
pelvic pain
uterine bleeding

Full details

Risk factors

extremes of maternal age
prior molar pregnancy
diminished dietary fat and carotene

Full details

Diagnostic tests

1st tests to order

histologic exam of placental tissue
serum human chorionic gonadotropin (hCG)
pelvic ultrasound

Full details

Tests to consider

CBC
serum PT, PTT
serum metabolic panel
serum thyroid-stimulating hormone (TSH)
blood type with antibody screen
CXR

Full details

Treatment algorithm

ACUTE

singleton molar pregnancy: desiring fertility

singleton molar pregnancy: not desiring fertility

viable twin fetus: elective termination not desired

viable twin fetus: elective termination

ONGOING

following initial management: high risk of gestational trophoblastic neoplasia with completed follow up unlikely

Contributors

Authors

Antonio Braga, MD

Associate Professor

Department of Obstetrics and Gynecology

Rio de Janeiro Federal University

Department of Maternal Child

Fluminense Federal University

Rio de Janeiro

Brazil

Disclosures

AB is an author of references cited in this topic.

Kevin M. Elias, MD

Assistant Professor

Brigham and Women’s Hospital

Dana Farber Cancer Institute

New England Trophoblastic Disease Center

Division of Gynecologic Oncology

Department of Obstetrics, Gynecology and Reproductive Biology

Harvard Medical School

Boston

Disclosures

KME has been a paid consultant for AOA Dx and received research support from Aspira Women’s Health and Abcam, Inc. KME is an author of references cited in this topic.

Neil S. Horowitz, MD

Associate Professor

Brigham and Women’s Hospital

Dana Farber Cancer Institute

New England Trophoblastic Disease Center

Division of Gynecologic Oncology

Department of Obstetrics, Gynecology and Reproductive Biology

Harvard Medical School

Boston

Disclosures

NSH is an author of references cited in this topic.

Ross S. Berkowitz, MD

William H. Baker Professor of Gynecology

Brigham and Women’s Hospital

Dana Farber Cancer Institute

New England Trophoblastic Disease Center

Division of Gynecologic Oncology

Department of Obstetrics, Gynecology and Reproductive Biology

Harvard Medical School

Boston

Disclosures

RSB is an author of references cited in this topic.

Acknowledgements

Dr Ross S. Berkowitz, Dr Kevin M. Elias, Dr Neil S. Horowitz, and Dr Antonio Braga would like to gratefully acknowledge Dr John Soper and Dr Emma Rossi, previous contributors to this topic. JS and ER declare that they have no competing interests.

Peer reviewers

Jane Stewart, PhD, MSc

Consultant Gynecologist

Subspecialist in Reproductive Medicine

Newcastle Fertility Centre at Life

Bioscience Centre

International Centre at Life

Newcastle upon Tyne

Disclosures

JS declares that she has no competing interests.

Philip Savage, PhD, FRCP

Consultant in Medical Oncology

Department of Medical Oncology

Charing Cross Hospital

London

Disclosures

PS declares that he has no competing interests.

Aparna Sundaram, DO, MBA, MPH

Physician Consultant

Preventive Medicine

Private Practice

Atlanta

Disclosures

AS declares that she has no competing interests.

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

Horowitz NS, Eskander RN, Adelman MR, et al. Epidemiology, diagnosis, and treatment of gestational trophoblastic disease: A Society of Gynecologic Oncology evidenced-based review and recommendation. Gynecol Oncol. 2021 Dec;163(3):605-13.Full text Abstract

Ngan HYS, Seckl MJ, Berkowitz RS, et al. Diagnosis and management of gestational trophoblastic disease: 2021 update. Int J Gynaecol Obstet. 2021 Oct;155 Suppl 1(suppl 1):86-93.Full text Abstract

Tidy, J, Seckl, M, Hancock, BW, on behalf of the Royal College of Obstetricians and Gynaecologists. Management of gestational trophoblastic disease. BJOG 2021;128: e1-e27.Full text

Lok C, van Trommel N, Massuger L, et al. Practical clinical guidelines of the EOTTD for treatment and referral of gestational trophoblastic disease. Eur J Cancer. 2020 May;130:228-40. Abstract

Reference articles

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

Differentials
- Hyperemesis gravidarum
- Spontaneous abortion
- Multiple gestation
More Differentials
Guidelines
- Epidemiology, diagnosis, and treatment of gestational trophoblastic disease
- Diagnosis and treatment of gestational trophoblastic disease
More Guidelines
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Molar pregnancies

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic tests

1st tests to order

Tests to consider

Treatment algorithm

singleton molar pregnancy: desiring fertility

singleton molar pregnancy: not desiring fertility

viable twin fetus: elective termination not desired

viable twin fetus: elective termination

following initial management: high risk of gestational trophoblastic neoplasia with completed follow up unlikely

Contributors

Authors

Antonio Braga, MD

Disclosures

Kevin M. Elias, MD

Disclosures

Neil S. Horowitz, MD

Disclosures

Ross S. Berkowitz, MD

Disclosures

Acknowledgements

Peer reviewers

Jane Stewart, PhD, MSc

Disclosures

Philip Savage, PhD, FRCP

Disclosures

Aparna Sundaram, DO, MBA, MPH

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

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