Placenta previa

Last reviewed: 27 Apr 2022
Last updated: 30 Mar 2022

Summary

Definition

History and exam

Key diagnostic factors

  • scarred uterus
  • presence of other risk factors
  • painless vaginal bleeding
  • absence of cervical/vaginal causes of bleeding on speculum examination
More key diagnostic factors

Other diagnostic factors

  • previous ultrasound anomaly in first trimester
  • lack of uterine tenderness
  • low blood pressure and tachycardia
Other diagnostic factors

Risk factors

  • advanced maternal age
  • multiple previous pregnancies
  • smoking
  • previous miscarriage
  • previous induced abortion
  • other placental abnormalities
  • short interpregnancy intervals
  • illicit drug use
  • uterine scarring (most commonly due to prior cesarean section)
  • infertility treatments
  • prior placenta previa
More risk factors

Diagnostic investigations

1st investigations to order

  • uterine ultrasound with color flow Doppler analysis
  • CBC
  • type and crossmatch
More 1st investigations to order

Investigations to consider

  • MRI placenta
  • INR/PTT, fibrinogen, and fibrinogen degradation products
  • Kleihauer-Betke test
More investigations to consider

Treatment algorithm

INITIAL

bleeding with unknown placental position

ACUTE

bleeding with known placenta previa

placenta previa with no bleeding

with miscarriage or elective termination

Contributors

Authors

Janet R. Albers, MD
Janet R. Albers

Professor

Department Chair

Family and Community Medicine

Southern Illinois University School of Medicine

Springfield

IL

Disclosures

JRA declares that she has no competing interests.

Thomas H. Miller, MD

Professor

Clinical Family and Community Medicine

Associate Chairman - Western Region

Southern Illinois University School of Medicine

Springfield

IL

Disclosures

THM declares that he has no competing interests.

Acknowledgements

Dr Janet R. Albers and Dr Thomas H. Miller would like to gratefully acknowledge Dr Robert Ewart and Dr Matthew Hagermeyer, previous contributors to this topic.

Disclosures

RE and MH declare that they have no competing interests.

Peer reviewers

Yosra Tahir Jarjees, MD

Assistant Professor

Head of Department of Obstetrics and Gynecology

Mosul College of Medicine

Mosul

Iraq

Disclosures

YTJ declares that he has no competing interests.

John Bachman, MD

Consultant in Family Medicine

Parker D Sanders and Isabella Sanders Professor of Primary Care

Rochester

MN

Disclosures

JB declares that he has no competing interests.

  • Placenta previa images
  • Differentials

    • Normal labor
    • Placental abruption
    • Miscarriage
    More Differentials
  • Guidelines

    • Guideline no. 402: diagnosis and management of placenta previa
    • Guideline no. 402: diagnosis and management of placenta previa
    More Guidelines
  • Patient leaflets

    Premature labor

    More Patient leaflets
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