Foundations of Perinatal Genetic Counseling

Preface

Acknowledgments

Common Abbreviations

1. Pregnancy Basics

1.1 Pregnancy Timeline and Dating

Pregnancies are Counted in Weeks Gestational Age versus Embryonic Age Normal Pregnancy Timeline and Duration Methods for Dating Guidelines and Recommendations for Determining Dating Tools Available for Calculating Gestational Age

1.2 Pregnancy Care

Types of Prenatal Providers Routine Prenatal Visits Prenatal Panel Complete Blood Count Blood Type and Antibody Testing HbA1c for Diabetes Fetal Imaging Complicated Pregnancies

1.3 Documenting a Pregnancy History

Gravida and Para Calculating Gravidity and Parity (G's and P's)

2. The Perinatal Genetic Counseling Appointment and Family History

2.1 The Perinatal Genetic Counseling Session

2.2 Obtaining a Pregnancy History

2.3 Obtaining a Family History

2.4 Interpreting a Family History

Mendelian Conditions Multifactorial Conditions Consanguinity Birth Defects Intellectual Disability and Autism Pregnancy Loss and Infertility Unknown Etiologies Accuracy Other Conditions (Referrals)

2.5 Unique Situations in the Perinatal Family History

Gamete Donation Same Sex Couples Surrogacy Adoption Ethnicity

3. Prenatal Screening

3.1 Evaluation of a Screen

Sensitivity Specificity Positive Predictive Value Negative Predictive Value Personal Utility

3.2 Prenatal Screening Options

Maternal Serum Screening

Multiples of the Median (MoM) Calculating the Risk Timing and Test Options Results Pattern Association Follow up of Abnormal Results Limitations of Maternal Serum Screening

Cell Free DNA Testing

Origin Fetal fraction Clearance Methodology Conditions Analyzed Test performance Who to offer testing to? Multiples and Vanishing Twins Adverse Pregnancy Outcomes Considerations Prior to Testing Results and Follow up Resources

4. Prenatal Diagnosis

4.1 Techniques

Chorionic Villus Sampling

Twins Risks Limitations

Amniocentesis

Twins Risks

4.2 Testing Options

Karyotype Fluorescence in situ Hybridization (FISH) Microarray Molecular Testing AFP &AChE Other Testing

4.3 Indications for Diagnostic Testing

5. Common Indications

5.1 Age Related Risks

Maternal Age Paternal Age

5.2 Personal and Family History

Single Gene Conditions Aneuploidy Multifactorial Conditions Birth Defects Intellectual Disability/Developmental Delay/Autism Consanguinity

5.3 Ultrasound Anomalies

Counseling for Ultrasound Anomalies

Classification of Ultrasound Findings

Estimating Risks

Ultrasound Findings in Pregnancies with Aneuploidy

Down syndrome Trisomy 18 Trisomy 13 Turner Syndrome Triploidy Common Ultrasound Findings Hallmark Ultrasound Findings Associated with Genetic Conditions Open Neural Tube Defects

5.4 Teratogens

5.5 Recurrent Pregnancy Loss, Stillbirth, and Infertility

Evaluation of Pregnancy Loss and Stillbirth

Evaluation of Infertility

Male Infertility Female Infertility

5.6 Preconception Counseling

6. Carrier Screening

6.1 Background

Who Should be Offered Carrier Testing? Carrier Screening for Gamete Donors Timing of Screening Evaluating Risks Positive Test Results Negative Results and Residual Risks Other Types of Results Application of a High Risk Result Repeat Testing Newborn Screening

6.2 Condition Directed or Ethnicity Based Testing

Cystic Fibrosis Spinal Muscular Atrophy FMR1-Related Disorders Ashkenazi Jewish and French Canadian/Cajun Hemoglobinopathies Family History

6.3 Expanded Carrier Testing

7. Pregnancy Management

7.1 Reproductive Options

Continuation of Pregnancy Adoption Termination

First Trimester Second Trimester Later Term Twins

7.2 Pregnancy Management Referrals

Maternal-Fetal Medicine Specialist Specialized Imaging

3D Ultrasound Echocardiography MRI

Cardiology Neonatology Fetal Surgery/Intervention Pediatric Surgery Pediatric Specialists Pathology/Autopsy Palliative Care/Hospice

7.3 Support Referrals and Bereavement

8. Assisted Reproductive Technology and Reproductive Options for the At Risk Couple

8.1 Reproductive Options for At Risk Couples

8.2 Assisted Reproductive Techniques

8.3 Preimplantation Genetic Testing

Preimplantation Genetic Screening (PGS) Preimplantation Genetic Diagnosis (PGD)

9. Common Perinatal Genetic Counseling Situations

9.1 Pregnancy Termination Misinterpreted Intent Patient Provider Conflict

9.2 Incidental Findings

Misattributed Paternity Discovery of Consanguinity Identification of an Incidental Condition

9.3 Privacy and Confidentiality

Genetics is a Family Affair Secret Information

9.4 Working with couples

Couples in Conflict "It's not my body"

9.5 Dealing with Uncertainty

Fetal Diagnosis and Prognosis Family History Complex Conditions Variants of Uncertain Significance

9.6 Fetal Sex Disclosure

Patient's Desire to Know or Not Testing may Reveal Sex Chromosome Abnormalities (SCAs) Disorders Affecting a Specific Sex Testing Only for Sex Fetal Sex may be "Difficult News"

9.7 Patient Questions

"What would you do?" When You Don't Know the Answer

9.8 Testing a Fetus for Adult Onset Condition

9.9 Barriers for Consent

Patient Understanding Voluntary Participation

9.10 Rapidly Evolving Technologies

Appendix A

Appendix B Index