Approximately 6 million pregnancies occur each year in the United States. Of this number, approximately 4 million result in live births and 600,000 are lost due to miscarriage. Genetic abnormalities are a common cause of miscarriage and congenital malformations. Nearly half of all miscarriages are associated with abnormal karyotypes and occur during the first few weeks of pregnancy. Genetic abnormalities also cause many birth defects.
Amniocentesis and chorionic villus sampling are among the screening tests traditionally used to identify fetal chromosomal aneuploidies (see TABLE on pages S4-S5). While they can provide a definitive diagnosis, these procedures are invasive and carry a small risk of miscarriage. Evolving diagnostic tests use maternal blood samples and are based on DNA sequencing technologies. These tests are noninvasive and do not carry the risk of miscarriage. Noninvasive cellfree DNA prenatal testing, or NIPT, is associated with nearly 100% sensitivity and specificity in the detection of trisomies 21, 18, and 13. It can be used in pregnant patients who are at both a normal or increased risk of fetal aneuploidies.
In August 2020, the American College of Obstetricians and Gynecologists (ACOG), in collaboration with the Society for Maternal-Fetal Medicine, published ACOG Practice Bulletin #226 entitled “Screening for Fetal Chromosomal Abnormalities.” The purpose of this Practice Bulletin is to provide ObGyn clinicians with the most current information regarding the benefits, performance characteristics, and limitations of the available screening test options for fetal chromosomal abnormalities. The introduction to the Practice Bulletin states: “This Practice Bulletin has been revised to further clarify methods of screening for fetal chromosomal abnormalities, including expanded information regarding the use of cell-free DNA in all patients regardless of maternal age or baseline risk, and to add guidance related to patient counseling.”
The articles that comprise this journal supplement will often reflect and expand upon the information presented in the ACOG Practice Bulletin. After reading this supplement, it is hoped that learners will possess the information necessary to better counsel their patients regarding NIPT and be able to more efficiently and effectively implement NIPT into their clinical practices.
To receive CME credit, please read the articles and go to www.omniaeducation.com/NIPT to access the post-test and evaluation.
This supplement is designed to provide ObGyn clinicians with current information on the cell-free DNA screening test options available for fetal chromosomal abnormalities. These screening tests are commonly referred to as Noninvasive Prenatal Screening (NIPS). In August 2020, the American College of Obstetricians and Gynecologists (ACOG) issued a Practice Bulletin entitled “Screening for Fetal Chromosomal Abnormalities” (PB #226). This Practice Bulletin included expanded information regarding the use of NIPS in all patients regardless of maternal age or baseline risk. It also identified NIPS as the most sensitive and specific test for screening for the most common aneuploidies. The authors of this supplement provide additional information on the technology, performance, and clinical utilization of NIPS testing.
Ann Early has nothing to disclose.
Genevieve L. Fairbrother MD, MPH, FACOG has nothing to disclose.
Morry Fiddler, PhD receives a salary from Insight Medical Genetics.
Barry A. Fiedel, PhD has nothing to disclose.
Amanda Hilferty has nothing to disclose.
Robert Schneider, MSW has nothing to disclose.
Lee P. Shulman, MD, FACMG, FACOG receives consulting fees from Biogix, Celula, Cooper Surgical, Natera, and Vermillion/Aspira and is a speaker for Bayer, Lupin Pharmaceuticals, Inc., and Myriad.
Andrew F. Wagner, MD, FACMG, FACOG has nothing to disclose.
Haichuan Zhang, PhD has ownership interest in Celula China Medical Technology Co.
After participating in this educational activity, participants should be better able to:
- Overcome barriers and demonstrate competency in integrating ACOG/Society for Maternal-Fetal Medicine Noninvasive Prenatal Testing Committee Opinions/Practice Bulletins recommendations into clinical decisionmaking surrounding prenatal visits for all pregnant patients.
- Explain the benefits and disadvantages of traditional fetal chromosomal aneuploidy screening tests compared with noninvasive screening tests.
- Define the technology that is the basis of the various noninvasive screening tests, including the role that fetal fraction plays in influencing results.
- Explain the expanding role of NIPS in the general obstetrical population.
ACCREDITATION AND CREDIT DESIGNATION STATEMENTS:
Global Learning Collaborative (GLC) is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians.
Global Learning Collaborative designates this enduring material for a maximum of 1 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.
This activity is designed to meet the educational needs of the obstetrician and gynecologist, family physician, internal medicine physician, physician assistant, nurse practitioner, and certified nurse midwife.
This activity is supported by an independent educational grant from Roche Diagnostics.
The views and opinions expressed in this educational activity are those of the faculty and do not necessarily represent the views of GLC and Omnia Education. This presentation is not intended to define an exclusive course of patient management; the participant should use his/her clinical judgment, knowledge, experience, and diagnostic skills in applying or adopting for professional use any of the information provided herein. Any procedures, medications, or other courses of diagnosis or treatment discussed or suggested in this activity should not be used by clinicians without evaluation of their patients’ conditions and possible contraindications or dangers in use, review of any applicable manufacturer’s product information, and comparison with recommendations of other authorities. Links to other sites may be provided as additional sources of information. Once you elect to link to a site outside of Omnia Education you are subject to the terms and conditions of use, including copyright and licensing restriction, of that site.
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