Size and Date Discrepancies

Question 1

Define small for gestational age (SGA)

Answer 1

≤10th percentile

Question 2

Define very small for gestational age (VSGA)

Answer 2

<3rd percentile

• associated w/ increased risk of poor outcome
• often associated w/ IUGR

Question 3

IUGR vs SGA

Answer 3

IUGR = growth restriction

VS

SGA = constitutionally small

• if otherwise normal, no intervention required
• no antenatal surveillance required

Question 4

What is the best method to identify SGA vs IUGR?

Answer 4

customized growth potential: assesses individual growth potential for each baby in each pregnancy based on:

• fetal sex
• maternal height
• weight
• parity
• ethnic origin

Question 5

Define IUGR/FGR

Answer 5

fetus that fails to reach potential growth

OR

failure of fetus to achieve genetic growth potential in utero

Question 6

What are the 4 underlying etiologies of IUGR?

Answer 6

1) aneuploidy
2) viral infection
3) nonaneuploid syndromes
4) placental insufficiency

Question 7

What are maternal prepregnancy conditions that are associated w/ IUGR?

Answer 7

• HTN
• pre-GDM
• renal disease
• autoimmune disease
• thrombophilias
• severe anemia, malabsorptive disease, malnutrition
• 20>BMI>/=30
• high altitutude
• tobacco/substance abuse

Question 8

What are pregnancy conditions that are associated w/ IUGR?

Answer 8

• multiple gestation
• inadequate weight gain (esp low protein intake)
• placental abnormalities (e.g. previa, abruption, mosaicism)
• relative hypoglycemia (i.e. “flat response” on 3h GTT)

Question 9

How does symmetric IUGR occur?

Answer 9

early alteration in process of cell division –> smaller number and size of cells

• occurs during hyperplasia
• fetal cell number decreased

Question 10

When/How can symmetric IUGR be seen?

Answer 10

at early 2nd tri U/S

• uniform diminishment of fetal organs, length, body weight
• body and head growth usually similarly affected

Question 11

What causes symmetric IUGR?

Answer 11

genetic, infectious, or teratogenic insults

1) chromosomal or congenital anomalies
2) infections (e.g. CMV, rubella)
3) teratogens (e.g. smoking, alcohol, cocaine, narcotics, valproate)

Question 12

What are antenatal interventions for symmetric IUGR?

Answer 12

there aren’t any!

not usually improved w/ antenatal interventions

Question 13

How does asymmetric IUGR occur?

Answer 13

• occurs during hypertrophy
• fetal cell number normal
• cell size is small

Question 14

What does asymmetric IUGR look like?

Answer 14

• abdomen and lower body experience delay

- head growth spared

Question 15

What maternal conditions are risk factors to assymetric IUGR?

Answer 15

• uteroplacental insufficiency
• maternal HTN (preeclampsia)
• malnutrition (esp protein/glucose restriction)
• diabetes
• renal disease
• placental abnormalities
• multiple gestation
• autoimmune disorders
• hemoglobinopathies

Question 16

What are antenatal interventions for asymmetric IUGR?

Answer 16

• nutrition
• hydration
• improvement of uteroplacental blood flow
• optimize timing of delivery

Question 17

What are fetal risk factors for IUGR?

Answer 17

1) chromosomal or congenital anomalies
2) teratogen exposure
3) fetal infection
4) genetic disorders
5) structural abnormalities

Question 18

What are neonatal risks associated w/ IUGR?

Answer 18

1) increased risk respiratory distress, NEC, intraventricular hemorrhage, clotting disorders, multiorgan failure
2) increased mortality
3) meconium aspiration
4) hypoglycemia
5) electrolyte abnormalities
6) hypocalcemia
7) impaired renal function
8) polycythemia, anemia, thrombocytopenia, hyperbili
9) hypothermia

Question 19

What is prognosis of IUGR?

Answer 19

• expected to have normal growth curves and height as adults, esp if IUGR only close to delivery
• earlier onset/prolonged IUGR may be related to growth lag
• head circumference <10th percentile –> 2-3x more serious neuro sequelae

Question 20

Define oligohydramnios

Answer 20

AFI≤5cm or DVP≤2cm

Question 21

What are possible causes of early onset oligo?

Answer 21

1) renal agenesis
2) renal dysplasia
3) renal obstructive disorders

–> lack of urine production OR inability to pass urine produced

4) HTN
5) IUGR

Question 22

What are possible causes of 3rd tri oligo?

Answer 22

1) uteroplacental insufficiency
2) prolonged pregnancy (>42wks –> fluid volume decrease)
3) idiopathic - resolves w/ time or w/ hydration

Question 23

What are risks associated w/ oligo at 42wks?

Answer 23

1) meconium stained amniotic fluid
2) fetal intolerance of labor
3) NICU admission
4) increased perinatal morbidity and mortality

Question 24

What is the clinical hallmark of IUGR?

Answer 24

fundal height < 3cm from sure dates

Question 25

How should S

Answer 25

- evaluate for PPROM | - order U/S (anatomy, AFV)

Question 26

How should IUGR be managed?

Answer 26

- serial Doppler blood flow studies - serial growth scans q3-4wks (include BPD, HC/AC ratio, EFW, AFV) - ongoing fetal surveillance (NST, mBPP)

Question 27

Define large for gestational age (LGA)

Answer 27

>/= 90th percentile

Question 28

Define macrosomia

Answer 28

nondiabetic gestational carrier: 4500g diabetic gestational carrier: 4000g

Question 29

Define polyhydramnios

Answer 29

AFV>2100ml or AFI >/= 25cm or DVP>8cm

Question 30

What are risk factors for macrosomia?

Answer 30

1) DM 2) abnormal 1h GTT w/ normal 3h GTT 3) hx of infant>4000g 4) maternal prepregnant obesity 5) excessive prenatal weight gain 6) prolonged pregnancy 7) fetal male sex 8) high paternal birth weight

Question 31

What are fetal causes of poly?

Answer 31

1) congenital anomalies 2) GI disorders 3) CNS disorders (e.g. anencephaly, NTDs) 4) cystic hygromas 5) nonimmune hydrops 6) genetic syndromes 7) congenital infections 8) placental abnormalities 9) twin gestation 10) twin-to-twin transfusion

Question 32

What are maternal causes of poly?

Answer 32

1) idiopathic 2) poorly controlled DM 3) maternal-fetal hemorrhage

Question 33

What are risks associated w/ poly?

Answer 33

1) macrosomia 2) cardiac anomalies 3) aneuploidy 4) PTB 5) fetal intolerance of labor 6) meconium stained amniotic fluid 7) emergency c/s 8) cord pH<7 9) low 5min APGAR 10) increased NICU admission 11) placental abruption 12) PP hemorrhage

Question 34

What is management for macrosomia?

Answer 34

1) anatomy U/S to detect fetal anomalies as cause | 2) serial growth q3-4wks (include BPD, HC/AC ratio, EFW, AFV) - AC>35cm identifies 90% macrosomia

Question 35

Describe MOA of indomethacin

Answer 35

prostaglandin synthetase inhibitor - decreases production of fetal urine - increases fluid reabsorption by fetal lungs - increases amt of intermembranous fluid movement from fetus to gestational carrier

Question 36

What is the outcome of indomethacin?

Answer 36

reduces AFV w/in 24h

Question 37

How can indomethacin be used safely?

Answer 37

- 72h = safe time course | - avoid after 31-32wks --> premature closure of ductus arteriosus and renal abnormalities

Question 38

Describe amnioreduction

Answer 38

removal of 1-5L fluid - usually only done in setting of maternal cardiopulmonary decompensation d/t poly - repeated amnioreduction may prolong pregnancy