Antepartum Testing

Question 1

Antepartum Fetal Surveillance

Answer 1

• NST
  
  • –> NR –> Full BPP –> 8 –> Repeat 2x weekly
  • –> Normal –> Repeat 2x weekly
• AFI
  
  • –> Normal –> Repeat 2x weekly
  • –> Oligohydramnios
    
    • > 36 weeks –> delivery
    • < 36 weeks –> expectant mgmt if NST is normal

Question 2

Amniotic Fluid Volume Assessment

Answer 2

Consists of fetal urine and fetal lung fluid

• Near-term fetus produces approx 1,000-1,500 ml of urine and a net of 150-170 of fetal lung fluid daily
• Fetal swallowing removes 500-700 ml amniotic fluid and intramembranes resorb 420 ml of amniotic fluid

Question 3

Clinical measurement of amniotic fluid

Answer 3

AFI: measure vertical diameters of the largest pocket in each quadrant and add 4 measurements together

MVP: vertical dimension of the largest fluid. pocket not containing cord or fetal parts

Question 4

Oligohydramnios

Answer 4

AFI < 5 or MVP < 2

AFI 5-8 cm = borderline

Oligohydramnios ass with IUGR and preterm birth

Question 5

Oligohydramnios

Etiology

Answer 5

• Maternal: dehydration, HTN, renal disease
• Fetal: Renal agenesis, GU obstruction, maternal vascular disease –> impaired fetoplacental perfusion
• Pregnancy complications: PROM, post-term, IUGR, uteroplacental insufficiency

Question 6

BPP

Answer 6

Variables:

• Breathing: at least 1 episode of > 30 seconds of sustained breathing in 30 min of observation under US
• Body movement: > 3 discrete body/limb mvmts in 30 min
• Fetal tone: > 1 episode of extension of extremity with return to flexion, or opening or closing of hang
• Reactive NST: > 2 accels in 30 min
• AF volume: > 1 pocket of amniotic fluid > 2 cm or AFI > 5

Earliest indicator to last indicator in fetal compromise:

NST –> breathing –> mvmt –> tone

Question 7

Mgmt Based on BPP Scores:

8-10

6

4

0-2

Answer 7

8-10: repeat 2x weekly

6: consider delivery if > 36 weeks, deliver if oligo
4: delivery if > 36 weeks; if < 32 weeks, repeat BPP in 4-6 h
0: delivery

If pt is dehydrated, give 2 L of water orally then recheck amniotic fluid

Question 8

Polyhydramnios

Answer 8

AFI > 24-25 or MVP > 8

Question 9

Polyhydramnios

Etiology

Answer 9

• Fetal upper GI obstruction
• Anencephaly
• Genetic disorder
• Maternal DM
• Fetal neuromuscular disorder

Question 10

Modified BPP

Answer 10

Combines NST and AFI; most commonly used tool for antenatal testing

• NST: reflects fetal well-being at time of testing
• AFI: used as long-term indicator of uteroplacental function