Download Intrauterine Growth Restriction

Intrauterine Growth Restriction
Eric H. Dellinger, MD
Greenville Hospital System
IUGR: Introduction
• IUGR 2nd leading contributor to PNM rate
• PNM rate increased 6-10 fold
• PNM rate 8/1000 background:
– 120/1000 for all IUGR
– 60-80/1000 when anomalies excluded
IUGR: Introduction
• 40% of stillbirths have IUGR
– 53% of preterm stillbirths
– 26% of term stillbirths
• Intrapartum asphyxia reported in up to 50%
of IUGR fetuses
• > 60% of IUGR fetuses with FHR tracing
abnormalities have hypoxia/acidosis
• Pardi, NEJM 328:692, 1993
When is small, too small? Defining IUGR
IUGR: Definition
• Birth weight < 10th percentile used to
define growth restriction at birth
• Definition carried over to fetuses using
ultrasound measurements (+/- 15%)
• Using 10th percentile, 70% will be
constitutionally small (no increase risk)
• Two SD = less than 3rd percentile
• AC < 2.5th percentile has 95% sensitivity
Perinatal Mortality / 1000 LB
IUGR: PNM and EFW
200
180
160
140
120
100
80
60
40
20
0
> 10
10
9
8
7
6
5
4
Birth Weight (percentile)
3
2
1
0.5
Background Information
Normal Versus Abnormal
Normal Versus Abnormal
< 10th Percentile
70% Normal
(Constitutional IUGR)
30% Abnormal
(Pathological IUGR)
IUGR: Etiology
Fetal / Placental
Chromosomal / Genetic
Twins
Congenital malformation
Infectious disease
CMV
Toxoplasmosis
Rubella
Placental pathology
Previa
Abruption
Mosaiacism
Infarction
Maternal
History of IUGR
Hypertension
Diabetes
MSAFP increase
APS
Chronic illness
Weight < 90% IBW
Hemoglobinopathy
Substance abuse
Anemia/Hypoxia
Past History of IUGR
• Prior history #1 risk factor for subsequent
IUGR
• 1 prior episode:
25% recurrence
• 2 episodes:
Fourfold increase
• 1/3 population “at risk”: 2/3 IUGR babies
• 2/3 population “low risk”: 1/3 of the IUGR
babies, but most are constitutional
IUGR: Diagnosis
• The Fundal Height Myth:
– best from 20-32 weeks: lightening
– lag of 4 cm suspicious
– Sensitivity of 27%, PPV of 18%
• Fundal height of limited value
– risk factors more predictive
IUGR: Fetal Measurements
• Have you weighed a fetus lately?
– EFW derived indirectly
• “Normal” growth curves difficult to establish
• PTL strongly associated with IUGR
– BW derived charts inaccurate
• U/S growth curves more accurate over
preterm age ranges
IUGR: Fetal Growth Patterns
When did you last watch a fetus grow?
Strategy
Strategy
• Normal versus abnormal
• Symmetric versus asymmetric
• Fetal causes
– Anomalies, arrhythmias, infection
•
•
•
•
Placental problems
Amniotic fluid
Dopplers
Fetal surveillance
HC/AC Ratios
Weeks
Ratio
<32
> 1.0
32-34
~ 1.0
>34
< 1.0
Asymmetric
Symmetric
HC preserved, ratio > 1.0
HC, AC both small, ratio ~ 1.0
IUGR: HC/AC Ratios
Asymmetric
Symmetric
HC
HC
HC/AC
AC
HC/AC
AC
Asymmetric vs. Symmetric
Asymmetric
Symmetric
Utereo-placental
Constitutional
Aneuploidy
Infection
Fetal Causes
•
•
•
•
Aneuploidy
Anomalies
Arrhythmias
Infection
Aneuploidy
Anomalies
Arrhythmias
Infection
Placental Causes
Amniotic Fluid Volume
IUGR: Oligohydramnios
• Initial harbinger of doom
– IUGR, preeclampsia
– may precede abnormal HC/AC
• Fluid pocket of BPP:
–
–
–
–
>2 cm
6% IUGR
1-2 cm
20% IUGR
<1 cm
39% IUGR
also predicts intrapartum distress