Updated: 4/17/2020

Alpha-fetoprotein (AFP)

0%
Topic
Review Topic
0
0
Topic
  • Snapshot
    • A 36-year-old G1P2 woman returns to clinic for a regularly scheduled obstetric visit at 20 weeks. Two weeks ago, she had serum labs drawn for a quadruple screen. Her alpha-fetoprotein (AFP) level was found to be decreased. She undergoes further testing and evaluation for possible fetal genetic disorders.
  • Introduction
    • Overview
      • measured routinely in maternal serum around 16-18 weeks (second trimester)
      • assesses for neural tube defects or genetic conditions
    • Associated conditions (abnormal AFP)
      • neural tube defects
      • trisomies
      • abdominal wall defects
  • Epidemiology
    • 50/1,000 pregnant women have abnormal AFP
    • 1-2/1,000 pregnant women will go on to deliver infants with related medical issues
  • Pathogenesis
    • Produced by yolk sac, gastrointestinal (GI) tract, and fetal liver
    • Secreted by fetal kidney into amniotic fluid and passes through placenta into maternal serum
    • High concentration in fetal life, minimal in adulthood
  • Imaging
    • Ultrasound
      • indications
        • abnormal AFP
      • views
        • transvaginal
  • Studies
    • Serum labs
      • evaluate AFP in association with
        • beta-human chorionig gonadotropin (β-hCG)
        • pregnancy-associated plasma protein A (PAPP-A)
        • inhibin A
        • estriol
    • Invasive
      • amniocentesis
        • indications
          • uncertain or normal ultrasound findings after positive maternal serum alpha-feto protein (MSAFP) screen
  • Differential
    • Elevated maternal serum AFP
      • neural tube defects
        • anacephaly
        • meningomyelocele
        • encephalocele
      • abdominal defects
        • gastroschisis
        • omphalocele
      • twin gestations
      • gestational age (GA) is older than was dated
        • incorrect GA is most common cause of abnormal AFP
    • Decreased maternal serum AFP
      • Trisomy 21 (Downs syndrome)
      • Trisomy 18 (Edwards syndrome)
      • GA is younger than was dated

Please rate this review topic.

You have never rated this topic.

Thank you. You can rate this topic again in 12 months.

Flashcards (0)
Cards
1 of 0
EXPERT COMMENTS (2)
Private Note