Case 9: Rosemary and Tony

Pregnancy Care: Pre-Conception

Genetic counselling

Conception timing: Delay if…

• Live vaccine

• Recent travel

• Recent teratogenic med use

• Bariatric surgery

• Recent live birth

Vaccines

• MMR

• Varicella

Diet

• Vit + mineral supplementation (folic acid)

• Decrease seafood

Pregnancy Care: Antenatal General

Diet:

• Increase calories

• Vit + mineral supplementation

• Limit caffeine

• No alcohol

• No seafood

Lifestyle:

• Exercise

• Travel precautions

Pregnancy Care: Antenatal 1st Trimester

GTPALS history

• Gravida

• Term

• Premature

• Abortion

• Living

• Stillborn

Family medical history

Comorbidity screening

Genetic testing

US

• Pregnancy location

• Evaluate fetus

• Determine EDD

Pregnancy Care: Antenatal 2nd Trimester

Pregnancy complications (bleeding, fluids)

Physical exam

Comorbidity screening

US

• Evaluate fetus and amniotic fluid

• Placental location

Prenatal Screening Types

Enhanced first trimester screening (eFTS) → Triple screen

Multiple marker screening (MMS) → Quadruple screen

Non-invasive prenatal testing (NIPT)

Prenatal Screening: eFTS

Screen for trisomy 21 and 18

Maternal serum analysis

• Beta-hCG: Increased

• PAPP-A (pregnancy-associated protein A): Placental protein

  • Increased

• AFP (alpha-fetoprotein): Tumor marker

  • Decreased

US: Nuchal translucency

• Fluid-filled area behind fetal neck

• Enlarged (≥ 3mm) = Fetal aneuploidies

Indications: 10-15 weeks

• All patients

Positive = NIPT

Prenatal Screening: MMS

Screen for trisomy 21 and 18 + neural tube defects

Maternal serum analysis

• Beta-hCG

• AFP

• Unconjugated estriol: Weak estrogen

  • Decreased

• Inhibin A: Placental protein

  • Increased

Indications: 15-22 weeks

• Patients declining eFTS

Prenatal Screening: NIPT

Screen for trisomy 21, 18, 13

Maternal serum analysis

• Cell-free fetal DNA (genetic testing)

Indications: 10+ weeks

• All patients

Down Syndrome (Trisomy 21): Pathophysiology

3 copies of chromosome 21 = 47 chromosomes

• Meiotic Nondisjunction: 96%

  • Maternal/paternal nondisjunction in meiosis during oogenesis/spermatogenesis

• Translocation: 3-4%

• Mosaicism: 1-2%

Trisomy 21: Risk Factors

Increased maternal age

NOT hereditary

Trisomy 21: Clinical Presentation

5As:

• Advanced maternal age

• Duodenal atresia

• Atrioventricular septal defect (heart defects)

• AML/ALL

• Early onset Alzheimer

Shortened long bones

Trisomy 21: Investigations

Prenatal screening

US

Confirmatory diagnosis: DNA test

Trisomy 21 Investigations: Prenatal Screening

eFTS:

• High beta-hCG

• Low PAPP-A

• Nuchal translucency

NIPT:

• High beta-hCG

• High inhibin A

• Low free estriol

• Low AFP

Trisomy 21 Investigations: US

Nuchal translucency

Heart abnormalities

Absent nasal bone

Shorter long bones + 5th phalange

Echogenic bowel

Trisomy 21 Investigations: DNA Test

Amniocentesis: Transabdominal amniotic fluid extraction

Chorionic villus sampling: Chorionic tissue extraction

Percutaneous umbiilical cord sampling: Fetal blood sample from umbilical cord

Trisomy 21: Management

Monitor systems for malformations

• Cardiac screening + surgery