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Multifetal Pregnancy Workup

  • Author: Asha J Heard, MD, MPH, FACOG; Chief Editor: Ronald M Ramus, MD  more...
Updated: Mar 09, 2016


Ultrasound examination remains the most reliable method for diagnosis of multiple gestations. Chorionicity should be established as soon as possible during pregnancy because it can affect future management decisions. The optimal time for diagnosis is in the first trimester or early second trimester.[11]

The most reliable predictor of a dichorionic gestation is the presence of two separate placentas. However, if the placentas have fused by the time an ultrasound examination is performed, a dichorionic, diamniotic gestation can show evidence of a “twin peak” or “lambda” sign on ultrasound. This refers to a triangular portion of the chorion fused between two layers of amnion. See the images below.

Twin peak sign Twin peak sign
Twin peak sign Twin peak sign

A monochorionic, diamniotic gestation can have the presence of a “T” sign, which is the appearance of the amnion as it comes off the placenta at a 90° angle. See the image below.

"T" sign "T" sign

These signs can be more difficult to appreciate as the pregnancy progresses.

Contributor Information and Disclosures

Asha J Heard, MD, MPH, FACOG Assistant Professor of Obstetrics and Gynecology, Associate Residency Director, Director of Clinical Ultrasound, Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Louisiana State University Health Sciences Center

Asha J Heard, MD, MPH, FACOG is a member of the following medical societies: American College of Obstetricians and Gynecologists, American Institute of Ultrasound in Medicine, Society for Maternal-Fetal Medicine

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Chief Editor

Ronald M Ramus, MD Professor of Obstetrics and Gynecology, Director, Division of Maternal-Fetal Medicine, Virginia Commonwealth University School of Medicine

Ronald M Ramus, MD is a member of the following medical societies: American College of Obstetricians and Gynecologists, American Institute of Ultrasound in Medicine, Medical Society of Virginia, Society for Maternal-Fetal Medicine

Disclosure: Nothing to disclose.

Additional Contributors

Jordan G Pritzker, MD, MBA, FACOG Adjunct Professor of Obstetrics/Gynecology, Hofstra North Shore-LIJ School of Medicine at Hofstra University; Attending Physician, Department of Obstetrics and Gynecology, Long Island Jewish Medical Center; Medical Director, Aetna, Inc; Private Practice in Gynecology

Disclosure: Nothing to disclose.

Steven J Ralston, MD Associate Professor of Obstetrics and Gynecology, Harvard Medical School; Consulting Staff in Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Beth Israel Deaconess Medical Center

Steven J Ralston, MD is a member of the following medical societies: American College of Obstetricians and Gynecologists, American Society of Law, Medicine & Ethics, Association of Professors of Gynecology and Obstetrics, Society for Maternal-Fetal Medicine

Disclosure: Nothing to disclose.

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Twin peak sign
Twin peak sign
"T" sign
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