eMedicine Specialties > Obstetrics and Gynecology > Obstetrical Complications

Placenta Previa: Differential Diagnoses & Workup

Author: Saju Joy, MD, MS, Assistant Professor, Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Wake Forest University School of Medicine
Coauthor(s): Deborah Lyon, MD, Director, Division of Gynecology, Associate Professor, Department of Obstetrics and Gynecology, University of Florida Health Science Center at Jacksonville
Contributor Information and Disclosures

Updated: Aug 12, 2008

Differential Diagnoses

Abruptio Placentae
Cervicitis
Premature Rupture of Membranes
Preterm Labor
Vaginitis
Vulvovaginitis

Other Problems to Be Considered

Vasa previa
Cervical or vaginal laceration
Vaginal sidewall laceration
Miscarriage (spontaneous abortion)

Workup

Laboratory Studies

  • Although coagulopathy is a rare occurrence, a complete blood count with platelets is useful.
  • A disseminated intravascular coagulopathy (DIC) profile with prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, and fibrin split products may also be helpful.

Imaging Studies

  • The most useful and inexpensive study is transvaginal ultrasonography that provides 100% accuracy in identifying a placenta previa.
  • An alternative would be transabdominal ultrasonography that can be 95% accurate; however, the false-positive and false-negative rates can range from 2-25%. Translabial sonography is another alternative; however, it is often deferred to the accuracy, safety and tolerability of transvaginal sonography.
  • MRI may be used for planning the delivery in that it may help identify placenta accreta, placenta increta, or placenta percreta. These invasive placental abnormalities are more common (eg, placenta accrete occurs in up to 0.2% of pregnancies) due to the increase in cesarean deliveries, advancing maternal age, hypertensive disease, smoking, and placenta previa cases. Although in most situations, MRI is no more sensitive in diagnosing placenta accreta that ultrasonography, it may be superior for the posterior placenta accreta or the more invasive increta and percreta. For women at high risk for placenta accreta, a 2-step protocol that uses ultrasonography first and then MRI for cases with inconclusive ultrasonographic features may optimize diagnostic accuracy.

Other Tests

  • An ultrasonographic evaluation of the fetus is valuable in identifying current gestational age and weight, potential congenital anomalies, malpresentation, and evidence for fetal growth restriction. Ultrasonographic evaluation is also recommended in identifying umbilical cord insertion and excluding a velamentous insertion.
  • A sterile speculum examination should be performed to evaluate rupture of the fetal membranes.

More on Placenta Previa

Overview: Placenta Previa
Differential Diagnoses & Workup: Placenta Previa
Treatment & Medication: Placenta Previa
Follow-up: Placenta Previa
Multimedia: Placenta Previa
References
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References

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Further Reading

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Keywords

placenta previa, complete placenta previa, partial placenta previa, marginal placenta previa, low-lying placenta, placenta accreta, placenta increta, placenta percreta, cesarean delivery, cesarean hysterectomy, transvaginal sonography, transvaginal ultrasonography, tocolysis, continuous fetal monitoring, accreta, increta, percreta, transvaginal ultrasound

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Contributor Information and Disclosures

Author

Saju Joy, MD, MS, Assistant Professor, Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Wake Forest University School of Medicine
Saju Joy, MD, MS is a member of the following medical societies: American College of Obstetricians and Gynecologists, American Institute of Ultrasound in Medicine, American Medical Association, and Society for Maternal-Fetal Medicine
Disclosure: Nothing to disclose.

Coauthor(s)

Deborah Lyon, MD, Director, Division of Gynecology, Associate Professor, Department of Obstetrics and Gynecology, University of Florida Health Science Center at Jacksonville
Deborah Lyon, MD is a member of the following medical societies: American College of Obstetricians and Gynecologists, Association of American Medical Colleges, Association of Professors of Gynecology and Obstetrics, and Florida Medical Association
Disclosure: Nothing to disclose.

Medical Editor

Ronald Levine, MD, Director, Section of Gynecologic Endoscopy, Professor, Department of Obstetrics and Gynecology, University of Louisville School of Medicine
Ronald Levine, MD is a member of the following medical societies: American Academy of Allergy Asthma and Immunology, American College of Obstetricians and Gynecologists, American Medical Association, and Society of Laparoendoscopic Surgeons
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.

Managing Editor

Richard S Legro, MD, Professor, Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology, Pennsylvania State University College of Medicine; Consulting Staff, Milton S Hershey Medical Center
Richard S Legro, MD is a member of the following medical societies: American College of Obstetricians and Gynecologists, American Society for Reproductive Medicine, Endocrine Society, Phi Beta Kappa, and Society of Reproductive Surgeons
Disclosure: Nothing to disclose.

CME Editor

Frederick B Gaupp, MD, Consulting Staff, Department of Family Practice, Hancock Medical Center
Frederick B Gaupp, MD is a member of the following medical societies: American Academy of Family Physicians
Disclosure: Nothing to disclose.

Chief Editor

Carl V Smith, MD, The Distinguished Chris J and Marie A Olson Chair of Obstetrics and Gynecology, Professor, Department of Obstetrics and Gynecology, University of Nebraska Medical Center
Carl V Smith, MD is a member of the following medical societies: American College of Obstetricians and Gynecologists, American Institute of Ultrasound in Medicine, American Medical Association, Arkansas Medical Society, Association of Professors of Gynecology and Obstetrics, Central Association of Obstetricians and Gynecologists, Council of University Chairs of Obstetrics and Gynecology, Nebraska Medical Association, and Society for Maternal-Fetal Medicine
Disclosure: Nothing to disclose.

 
 
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