• American College of Obstetricians and Gynecologists (ACOG). Invasive prenatal testing for aneuploidy. Washington (DC): American College of Obstetricians and Gynecologists (ACOG); 2007 Dec. 9 p. (ACOG practice bulletin; no. 88). [50 references]

This is the current release of the guideline.

Fetal chromosomal abnormalities (fetal aneuploidy)

Counseling
Diagnosis
Risk Assessment
Screening

Medical Genetics
Obstetrics and Gynecology
Pediatrics

Physicians

• To aid practitioners in making decisions about appropriate obstetric and gynecologic care
• To provide clinical management guidelines for the prenatal diagnosis of fetal aneuploidies

All women, regardless of maternal age

Screening and Diagnosis

1. Risk assessment for fetal aneuploidy
2. Invasive testing for prenatal diagnosis of fetal chromosomal abnormalities
   • Amniocentesis
     • Traditional
     • Early (considered but not recommended)
   • Chorionic villus sampling
   • Cordocentesis (percutaneous umbilical blood sampling)
3. Laboratory tests to diagnose aneuploidy
   • Metaphase analysis of cultured amniocytes or chorionic villus cells
   • Fluorescence in situ hybridization analysis
   • Comparative genomic hybridization
4. Ultrasonography

Counseling

1. Prenatal counseling concerning risks and benefits of screening versus invasive diagnostic testing
2. Counseling of women with chronic hepatitis B or C virus infections, or human immunodeficiency virus infection
3. Nondirective counseling concerning pregnancy termination

• Procedure-related pregnancy loss rate
• Procedure-related complication rate
• Risk for chromosomal abnormalities
• Positive predictive value of diagnostic/screening tests for chromosomal abnormalities

Hand-searches of Published Literature (Primary Sources)
Hand-searches of Published Literature (Secondary Sources)
Searches of Electronic Databases

The MEDLINE database, the Cochrane Library, and the American College of Obstetricians and Gynecologists' own internal resources and documents were used to conduct a literature search to locate relevant articles published between January 1985 and June 2007. The search was restricted to articles published in the English language. Priority was given to articles reporting results of original research, although review articles and commentaries also were consulted. Abstracts of research presented at symposia and scientific conferences were not considered adequate for inclusion in this document. Guidelines published by organizations or institutions such as the National Institutes of Health and the American College of Obstetricians and Gynecologists were reviewed, and additional studies were located by reviewing bibliographies of identified articles.

Not stated

Weighting According to a Rating Scheme (Scheme Given)

Studies were reviewed and evaluated for quality according to the method outlined by the U.S. Preventive Services Task Force:

I Evidence obtained from at least one properly designed randomized controlled trial.

II-1 Evidence obtained from well-designed controlled trials without randomization.

II-2 Evidence obtained from well-designed cohort or case–control analytic studies, preferably from more than one center or research group.

II-3 Evidence obtained from multiple time series with or without the intervention. Dramatic results in uncontrolled experiments also could be regarded as this type of evidence.

III Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees.

Systematic Review

Not stated

Expert Consensus

Analysis of available evidence was given priority in formulating recommendations. When reliable research was not available, expert opinions from obstetrician–gynecologists were used. See also the "Rating Scheme for the Strength of Recommendations" field regarding Grade C recommendations.

Based on the highest level of evidence found in the data, recommendations are provided and graded according to the following categories:

Level A — Recommendations are based on good and consistent scientific evidence.

Level B — Recommendations are based on limited or inconsistent scientific evidence.

Level C — Recommendations are based primarily on consensus and expert opinion.

A formal cost analysis was not performed and published cost analyses were not reviewed.

Internal Peer Review

Practice Bulletins are validated by two internal clinical review panels composed of practicing obstetrician-gynecologists generalists and sub-specialists. The final guidelines are also reviewed and approved by the American College of Obstetricians and Gynecologists (ACOG) Executive Board.

The grades of evidence (I-III) and levels of recommendation (A-C) are defined at the end of the "Major Recommendations" field.

The following recommendation is based on good and consistent scientific evidence (Level A):

• Early amniocentesis (at less than 15 weeks of gestation) should not be performed because of the higher risk of pregnancy loss and complications compared with traditional amniocentesis (15 weeks of gestation or later).

The following conclusions are based on limited or inconsistent scientific evidence (Level B):

• Amniocentesis at 15 weeks of gestation or later is a safe procedure. The procedure-related loss rate after midtrimester amniocentesis is less than 1 in 300 to 500.
• In experienced individuals and centers, CVS procedure-related loss rates may be the same as those for amniocentesis.

The following recommendation and conclusions are based primarily on consensus and expert opinion (Level C):

• Invasive diagnostic testing for aneuploidy should be available to all women, regardless of maternal age.
• Patients with an increased risk of fetal aneuploidy include women with a previous fetus or child with an autosomal trisomy or sex chromosome abnormality, one major or at least two minor fetal structural defects identified by ultrasonography, either parent with a chromosomal translocation or chromosomal inversion, or parental aneuploidy.
• Nondirective counseling before prenatal diagnostic testing does not require a patient to commit to pregnancy termination if the result is abnormal.

Definitions:

Grades of Evidence

I Evidence obtained from at least one properly designed randomized controlled trial.

II-1 Evidence obtained from well-designed controlled trials without randomization.

II-2 Evidence obtained from well-designed cohort or case–control analytic studies, preferably from more than one center or research group.

II-3 Evidence obtained from multiple time series with or without the intervention. Dramatic results in uncontrolled experiments also could be regarded as this type of evidence.

III Opinions of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees.

Levels of Recommendation

Level A — Recommendations are based on good and consistent scientific evidence.

Level B — Recommendations are based on limited or inconsistent scientific evidence.

Level C — Recommendations are based primarily on consensus and expert opinion.

None provided

The type of supporting evidence is identified and graded for each recommendation (see "Major Recommendations").

Appropriate use of prenatal screening and diagnostic testing for fetal aneuploidy

Procedure-related maternal and fetal complications, including pregnancy loss, can occur with amniocentesis and chorionic villus sampling.

These guidelines should not be construed as dictating an exclusive course of treatment or procedure. Variations in practice may be warranted based on the needs of the individual patient, resources, and limitations unique to the institution or type of practice.

An implementation strategy was not provided.

Staying Healthy

Patient-centeredness
Safety
Timeliness

• American College of Obstetricians and Gynecologists (ACOG). Invasive prenatal testing for aneuploidy. Washington (DC): American College of Obstetricians and Gynecologists (ACOG); 2007 Dec. 9 p. (ACOG practice bulletin; no. 88). [50 references]

Not applicable: The guideline was not adapted from another source.

2007 Dec

American College of Obstetricians and Gynecologists - Medical Specialty Society

American College of Obstetricians and Gynecologists (ACOG)

American College of Obstetricians and Gynecologists (ACOG) Committee on Practice Bulletins - Obstetrics

Not stated

Not stated

This is the current release of the guideline.

Proposed performance measures are included in the original guideline document.

This NGC summary was completed by ECRI Institute on July 30, 2008. The information was verified by the guideline developer on August 20, 2008.

This NGC summary is based on the original guideline, which is subject to the guideline developer's copyright restrictions.