Clinical Genetics Resources
Prenatal screening, diagnostic testing, genetic counseling, clinical workflows, and reference resources for maternal-fetal medicine and genetics professionals.
See also:
Genetic Counselor's Toolbox
for calculators, databases, laboratory resources, and additional genetics links.
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Genetic Counseling Services
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Prenatal Screening & Carrier Screening
- ACOG: Screening for Fetal Chromosomal Abnormalities JAN 2026
- SMFM Consult Series #74: Cell-free DNA screening for aneuploidies 2025
- ACOG Genetic Screening & Testing Topic Page
- ACOG: Carrier Screening
- ACMG Practice Resource: Carrier screening for autosomal-recessive and X-linked conditions
- California Prenatal Screening Program
- California PNS - Information for Prenatal Care Providers
- California Prenatal Screening Provider Handbook
Prenatal Diagnostic Testing & Genomic Testing
- SMFM Consult Series #41: Chromosomal microarray for prenatal diagnosis REAFFIRMED 2024
- ISPD Updated Position Statement: Genome-wide sequencing for prenatal diagnosis SMFM ENDORSED
- ACOG Practice Bulletin #162: Prenatal Diagnostic Testing for Genetic Disorders
- Perinatology.com: Prenatal Diagnostic Genetic Testing - Quick Reference
- NIH Genetic Testing Registry (GTR)
Patient & Family Education Resources
Prenatal Genetic Testing - Clinical Workflow
1. Offer options to all obstetric patients
Discuss prenatal screening and diagnostic testing regardless of maternal age or baseline aneuploidy risk. If screening is chosen, use one screening strategy rather than simultaneous independent screening tests.
Discuss prenatal screening and diagnostic testing regardless of maternal age or baseline aneuploidy risk. If screening is chosen, use one screening strategy rather than simultaneous independent screening tests.
2. Screening choice
cfDNA is the most sensitive and specific screening test for trisomies 21, 18, and 13, but it is not diagnostic. Serum screening remains an option when preferred or when cfDNA is not appropriate or available.
cfDNA is the most sensitive and specific screening test for trisomies 21, 18, and 13, but it is not diagnostic. Serum screening remains an option when preferred or when cfDNA is not appropriate or available.
3. Positive cfDNA result
Genetic counseling + detailed ultrasound evaluation + offer diagnostic confirmation with CVS or amniocentesis.
Genetic counseling + detailed ultrasound evaluation + offer diagnostic confirmation with CVS or amniocentesis.
4. Nonreportable / no-call cfDNA
Offer genetic counseling, comprehensive ultrasound, and diagnostic testing because nonreportable results are associated with increased aneuploidy risk. A repeat cfDNA attempt may be considered in selected circumstances based on gestational age, ultrasound findings, and likely cause of test failure.
Offer genetic counseling, comprehensive ultrasound, and diagnostic testing because nonreportable results are associated with increased aneuploidy risk. A repeat cfDNA attempt may be considered in selected circumstances based on gestational age, ultrasound findings, and likely cause of test failure.
5. Ultrasound remains important
Offer a second-trimester anatomic survey to all patients, regardless of the screening method used.
Offer a second-trimester anatomic survey to all patients, regardless of the screening method used.
Based on ACOG January 2026 guidance and SMFM Consult Series #74.
1. Define the indication
Known familial pathogenic variant, positive parental carrier screen, suggestive family history, consanguinity, or fetal phenotype suggesting a specific monogenic disorder.
Known familial pathogenic variant, positive parental carrier screen, suggestive family history, consanguinity, or fetal phenotype suggesting a specific monogenic disorder.
2. Confirm the molecular target when possible
For a known familial condition, identify the exact pathogenic variant(s) before fetal testing whenever feasible.
For a known familial condition, identify the exact pathogenic variant(s) before fetal testing whenever feasible.
3. Select the fetal assay
CVS or amniocentesis can provide material for targeted testing. Use a targeted assay when the familial variant is known; use a phenotype-directed panel when a defined group of genes is suspected.
CVS or amniocentesis can provide material for targeted testing. Use a targeted assay when the familial variant is known; use a phenotype-directed panel when a defined group of genes is suspected.
4. Avoid assuming CMA or exome answers every single-gene question
Repeat expansions, methylation disorders, and some other variant classes require specialized assays.
Repeat expansions, methylation disorders, and some other variant classes require specialized assays.
1. Fetal structural anomaly identified
Review phenotype, family history, exposures, and whether the findings suggest a recognizable syndrome.
Review phenotype, family history, exposures, and whether the findings suggest a recognizable syndrome.
2. Offer diagnostic testing
Chromosomal microarray should be offered when genetic analysis is performed for a fetus with one or more structural anomalies.
Chromosomal microarray should be offered when genetic analysis is performed for a fetus with one or more structural anomalies.
3. If chromosome-level testing is nondiagnostic
In selected pregnancies with a persistent suspicion for a genetic disorder, consider phenotype-directed gene testing or prenatal exome/genome sequencing with appropriate genetics expertise and pre/post-test counseling.
In selected pregnancies with a persistent suspicion for a genetic disorder, consider phenotype-directed gene testing or prenatal exome/genome sequencing with appropriate genetics expertise and pre/post-test counseling.
4. Reassess after additional imaging
A refined fetal phenotype may change the most appropriate laboratory test and improve interpretation.
A refined fetal phenotype may change the most appropriate laboratory test and improve interpretation.
CMA guidance: SMFM Consult #41, reaffirmed 2024. Prenatal sequencing: ISPD position statement endorsed by SMFM.
cfDNA Interpretation - Practical Points
Low-risk cfDNA
Substantially lowers risk for the conditions screened but does not exclude all chromosome abnormalities, genetic disorders, or fetal structural anomalies. Diagnostic testing remains an option later if new findings arise.
Substantially lowers risk for the conditions screened but does not exclude all chromosome abnormalities, genetic disorders, or fetal structural anomalies. Diagnostic testing remains an option later if new findings arise.
High-risk cfDNA
Do not treat a screening result as a fetal diagnosis. Provide genetic counseling and recommend confirmatory diagnostic testing.
Do not treat a screening result as a fetal diagnosis. Provide genetic counseling and recommend confirmatory diagnostic testing.
Nonreportable / no-call result
Do not assume the result is reassuring. Offer genetic counseling, comprehensive ultrasound, and diagnostic testing; repeat cfDNA may be reasonable only in selected situations.
Do not assume the result is reassuring. Offer genetic counseling, comprehensive ultrasound, and diagnostic testing; repeat cfDNA may be reasonable only in selected situations.
Sex chromosome aneuploidy
ACOG/SMFM recommend that sex chromosome screening be an opt-in choice with appropriate pretest counseling. Unexpected results may reflect fetal, placental, or maternal biology and require careful interpretation.
ACOG/SMFM recommend that sex chromosome screening be an opt-in choice with appropriate pretest counseling. Unexpected results may reflect fetal, placental, or maternal biology and require careful interpretation.
Microdeletion screening
Routine general-population cfDNA screening for microdeletion conditions is not recommended. Patients seeking information about fetal copy-number variants should be offered diagnostic testing rather than cfDNA microdeletion screening.
Routine general-population cfDNA screening for microdeletion conditions is not recommended. Patients seeking information about fetal copy-number variants should be offered diagnostic testing rather than cfDNA microdeletion screening.
Genetics Databases & Variant Interpretation
Professional Genetics Resources by Region
United States
Selected Current References
- American College of Obstetricians and Gynecologists. Screening for Fetal Chromosomal Abnormalities. Practice Advisory. January 2026.
- Rink BD, Dugoff L, Kuller JA. Society for Maternal-Fetal Medicine Consult Series #74: Cell-free DNA screening for aneuploidies: Updated guidance. 2025. Endorsed by ACOG.
- Dugoff L, Norton ME, Kuller JA. Society for Maternal-Fetal Medicine Consult Series #41: The use of chromosomal microarray for prenatal diagnosis. Reaffirmed 2024.
- Van den Veyver IB, Chandler N, Wilkins-Haug LE, Wapner RJ, Chitty LS; ISPD Board of Directors. Updated Position Statement on the use of genome-wide sequencing for prenatal diagnosis. 2022. Endorsed by SMFM.
- American College of Obstetricians and Gynecologists. Practice Bulletin #162: Prenatal Diagnostic Testing for Genetic Disorders.
- Gregg AR, Aarabi M, Klugman S, et al. Screening for autosomal recessive and X-linked conditions during pregnancy and preconception: an ACMG practice resource. Genet Med. 2021;23:1793-1806.
- California Department of Public Health. California Prenatal Screening Program - Information for Prenatal Care Providers. Accessed August 24, 2026.
External links were reviewed August 24, 2026. Stable professional-society and program landing pages are preferred
over fragile deep links whenever possible. Laboratory and society guidance may change; verify current recommendations
before clinical use.