Introduction to prenatal diagnosis Kathelijn Keymolen

Goals of PND To inform couples about the risk of a birth defect / genetic disorder in their pregnancy To give the couples the information to make an informed decision

Counseling before PND Uptake in prenatal diagnosis is the choice of the woman/ couple Non-directive counseling by geneticist, genetic counselor, gynecologist ... Option for psychological guidance in the decision-making process

Counseling before PND Personal and familial history of couple, consanguinity Carrier testing can be proposed according to prevalence of disorder Hb chromatography in Asian, African, Mediterranean people Tay Sachs, ..in Ashkenazi Jewish

Counseling before PND Explain Risk for affected fetus Detected disorders Risks , limitations of the procedures ( NIPT, invasive PND), general principles about the techniques Answering time Decisions to be considered after PND

Result of PND Absence of specific condition Reassurance Presence of specific condition Plan treatment/ follow-up (eg adrenogenital syndrome) Psychological preparation of parents/ family Termination of pregnancy

Result of PND VUS/ incidental findings/ variable expression/ reduced pentrance Importance of post-test counseling becomes more important with higher complexity of tests

Reasons for performing PND Advanced maternal age ≥ 35 years Risks for aneuploidy at amniocentesis 1/250 at 35y 1/200 at 36y 1/70 at 40y 1/25 at 44y

Reasons for performing PND Psychosocial reasons Reassurance in couples without an increased risk “NIPT for everybody” Medical staff Other caregivers Positive family history but low recurrence risk

Reasons for performing PND History of chromosomal anomaly Previous conceptus with aneuploidy ( eg Trisomy 21) NIPT Structural/ numerical chromosomal anomaly in a parent ( eg carrier of translocation) INVASIVE PND

Reasons for performing invasive PND Positive non-invasive screening Ultrasound NIPT

Reasons for performing invasive PND Specific monogenic condition in family History of an affected family member Parent with Marfan Child with cystic fibrosis Parent(s) healthy carriers HbS (AR) CF (AR) Fra X (XL)

Reasons for performing invasive PND US anomalies and maternal seroconversion CMV Fetal anemia Parvovirus Rhesus immunization

PND Evolving landscape ~ available techniques ~ reimbursement criteria ~ societal demands/ expectations

PND Multidisciplinary and dynamic approach Patient-centered