IUGR: A fetus that has not reached its growth potential.
Biometrical test: Test to meassure size
SGA: Small for gestational age (SGA) refer to fetal weight deviation in percent of standard deviation in relation to growth curve. Normally defined as below the 10 centile (86 % of median weight).
SGA includes IUGR and constitutionally small fetus (50-70% of SGA below 10% percentil).
The lower the birthweight centile, the higher the risk of intrauterine growth restriction = intrauterine growth retardation.
Traditionally divided into in:
Type I symmetrical 20%
Type II asymmetrical 80%
Biophysical test: Test to assess fetal well-being
for Gestational Age
||30 + 0
||34 + 0
||38 + 0
||40 + 0
||42 + 0
||-22% weight deviation » 2 SD
||-35% weight deviation » 3 SD
10% percentile ~ ca. 15% weight deviation
Causes and risk of IUGR:
5% percentile ~ 18% weight deviation
2,3% percentile ~ 2 SD ~ 22% pre-SD
1% percentile ~ 28% weight deviation
0,1% percentile ~ 37% weight deviation
- Previous IUGR
- More than two spontaneous abortions
- Fetal Factors:
- Karyotype abnormalities. This figure is higher if severe IUGR and if structural defects, normal liquor volume and normal uterine and umbilical artery Doppler flow are seen.
- placental mosaicism
- genetic syndrome
- major congenital abnormalities
- multiple gestation
- Placental injuries, mosaicism and abruption
- Thrombophilia related uteroplacental abnormalities
- Chronic inflammation
Gross placental structure anomalies
- Velamentorus insertion of umbilical artery
- Single umbilical artery
- Bilobate placenta
- Placenta previa
- Collagen/Vascular disease
- Antiphospholipid syndrome
- Renal disease, Myxoedem, anemia
Low calorie intake:
- Abuse (Smoking, Alcohol)
- Toxic (Antineoplastic)
- Famine World War II " 500 g
Complications of IUGR:
- Cyanotic heart disease
- Chronic pulmonary disease
- High attitude:
- 65 g for each 500 m above 2000 m
Fetal distress, Hypoxia, Acidosis and Low Apgar Score at
Increased perinatal morbidity and mortality
Grade 3-4 intraventricular haemorrhage
Metabolic disturbances and hypoglycemia
Impaired cognitive function and cerebral paresis
Measurements of fetal growth:
Symphysis - fundal distance (SF) in early studies reported sensivities of 56-86% and specificities of 80-93%. Seems best to predict early severe cases as both fetal weight and amnotic fluid decreases. However the impact of SF is uncertain.
Estimation of fetal weight by ultrasound.
In 5% of fetal weight estimation the real weight deviate > 14%.
Fetal wellbeing: movements by the mother.
Doppler flow and biophysical profile.
The risk of IUGR in patients with chronic hypertension increase with abnormal uterine notch. Growth is more important than size in predicting poor fetal outcome AC growth < 40 mm in 2 weeks are abnormal.
Use of Doppler in IUGR are associated with a reduction in perinatal death and induction of labor and less emergency cesarean sections (Cochrane).
Flow in uterine artery.
Increased flow especially in third trimester increases the risk for repeat IUGR and preeclampsia. The sensitivity is higher in II trimester than in I trimester. If normal at 22-24 weeks no further control seems indicated.
Uterin artery score:
- 0 Normal bilateral flow
- 1. One abnormal parameter Pulsatility Index (PI) in II trimester > 1,2 or notch
- 2. Two abnormal parameters
- 3. Three abnormal parameters
- 4. Four abnormal parameters
The parameters could be either high pulsatility index and or notch
Sequence of Doppler changes in severe IUGR < 32 weeks.
Early stage: Mild to moderate
- MCA (Middle Cerebral Artery). Pulsatility Index decreases
- UA (Umbilical Artery) pulsatility index increases
- Amniotic fluid drops.
- Umbilical artery end diastolic flow disappears = absent end diastolic flow (AEDF)
- Aorta pulsatility index increases (reduced short term variability).
- Decreased or reversed flow in ductus venous during late diastole
- UA (Umbilical Artery) Reverse flow (RF), Aorta reverse flow
- Ductus venosus reverse flow and vein pulsation in umbilical vein and inferior vena cava .
Some believe that fetal heart rate changes are late signs of fetal distress and believe venous Doppler changes comes early in the decompensated phase.
IUGR < 32-34 weeks umbilical artery Doppler and other fetal Doppler measurement may help in timing of the delivery in cases of severe IUGR at early gestational age, but is proven more useful in a context of serial measurements.
Do not consider delivery if there is normal umbilical artery flow, fetal movements and normal amnotic fluid.
Antenatal surveillance in gestational age < 32-34 weeks is unnecessary in fetus suspected for IUGR if umbilical artery Doppler is normal and fetal movement is registered by the mother and there is normal amount of amniotic fluid.
In preterm IUGR, absent or reversed umbilical artery blood flow (UA-AREDV) is strongly associated to perinatal mortality and acidosis: Ductus venosus Doppler most effectively identifies those preterm IUGR that are at higher risk of adverse neonatal outcome (particularly stillbirth) at least one week before delivery. Based on present observation a cut of value for ductus venosus flow of 2-3 SD seems to be most appropriate for delivery of GA below 30 weeks.
Absent or reversal of arterial velocity in the ductus venosus and pulsation in the umbilical vein have a high specificity [98%] and positive predictive value [82%].
Thus in very preterm IUGR fetuses an important intrauterine time can sometime be gained if venous flows are normal. However, only 50% of fetuses at risk for audosis develop abnormal venous flow. Therefore, additional tests like computerized cardiotocography and biophysical profile score are of value.
In case of abnormal umbilical flow 2 and 3, and brain sparring (MCA > 2 SD), biophysical profile do not add to outcome prediction.
- Deliver if CTG shows late deceleration,
- Abnormal venous flow 2-3 SD
- Reversed EDF by 31 weeks
- Absent in diastolic flow by 33 weeks
- Reduced EDF by 36 weeks
- Remember antenatal steriods before 34-(36) weeks
Waiting for these changes can cause Intra uterine fetal death and
neuro-developmental damage but this can also be
caused by early preterm delivery itself.
Spontaneous late decelerations often coincides with
pulsation in the umbilical vein or abnormal ductus
50% of the fetuses seem to have abnormal fetal heart rate before venous Doppler changes. Uterine artery notch increases the risk.
IUGR > 34-36 weeks
If IUGR (>=36 weeks < 5 percentile)~ --> 18% weight deviation: Delivery.
Umbilical Doppler > 32 weeks is not necessarily reassuring.
SGA fetuses with normal umbilical artery and abnormal
uterine and/or fetal middle cerebral artery waveforms
have an increased risk of fetal distress and being
delivered by cesarean section.
Deliver if in doubt
Normal biophysical profile (BPP), false negative stillbirth rate of 0.1 per 1,000 within 7 days.
Amniotic fluid index < 5th centile or £ 5 cm, a single cord-free pocket depth (< 1 cm, 2 x 1 cm, 2 x 2 cm) have all similar diagnostic accuracy, good negative predictive value in high risk pregnancies and rarely abnormal when Doppler findings is normal.
Change in biophysical profile
- No growth in 2-3 weeks
- CTG no acceleration
Abnormal Biophysical Profile and Doppler cerebral/umbilical ratio are associated with low umbilical artery pH, low apgar score and increased rate of cesarean section.
Abnormal Doppler normal precedes abnormal biophysical profile.
Action Plan In Case of IUGR
- Decreased variability
- No breathing movements
- Decline in amniotic fluid
- Loss of movement and tone
AED: absent and diastolic flow in umbilical artery. BPP: Biophysical profile
||25(0) – 31(6)
||32(0) – 36(6)
|-15% to -21%
||US /2-3 weeks
||US:/2-3 weeks or delivery
|-22% to -34%
||US: weeklyDoppler: AED C/S, but especially < 28 weeks followed by NST and Doppler daily and BPP twice weekly. Reverse diastolic flow, late deceleration and pulsative venous flow: C/S
||US: weeklyOligo & reverse diastolic flow:C/SAED: daily CTG, Doppler, weekly BPP If Deterioration, C/S
||Consider deliveryIf Doppler, CTG, BPP normal control 1 x 2 weekly, if AED/oligo/ NST nonreac-tive/ BPP £ 6:delivery
|| Karyotype (especially if normal flow and amniotic fluid). Antiphospholipids (APS), ANA, infections (TORCH), thrombophillia. If ANA and APS high levels consider heparin.Doppler: AED C/S but especially < 28 weeks followed by NST, and Doppler daily and BPP twice weekly. Reverse diastolic flow, late deceleration and pulsative venous flow: C/S.
||Karyotype (especially if normal flow and amniotic fluid). Antiphospholipids (APS), ANA, infections (TORCH), thrombophillia. If ANA and APS high levels consider heparin. AED: C/SIncrease P1 consider delivery even if CTG and BPP normal.
||Delivery. AED: C/S
Rules of Thumb for the Prognosis in Preterm Infants
Celeston & surfactant The prognose 1-2 weeks better than gestational age
|Normal among survivors
<85% of median weight The prognose 1 week worser than gestational age
<75% of median weight The prognose 2 weeks worser than gestational age
Prognosis for live born without abnormalities (ETFOL)
||Live born without severe handicaps
Association between gestational age and survival as well as survival with or without handicaps. Summery of Sandbjerg Guidelines
*: Percent of survivals
||Survivals, born after 1990
||Mild handicaps/ cognitive problems*
Prognosis without consideration to gestational age (GRIT 1999)
GRIT (Steve Thornton, presented at Course of fetal medicine, London 1999)
|| Neonatal mortality
||Severe handicaps at 2 year examination
||Dead or severe handicaps at the age of two
|Flow class 1
|Flow class 2
|Flow class 3
1) Axt-Fliedner R. et al. The value of uterine artery Doppler ultrasound in the prediction of severe complications in a risk population. Arch Gynecol Obstet, 2005 Jan;271(1):53-8. Epub 2004 Jun 3.
2) Bilardo CM, Wolf H, Stigter RH, Ville Y, Baez E, Visser GH, Hecher. Relationship between monitoring parameters and perinatal outcome in severe, early intrauterine growth restriction. Ultrasound Obstet Gynecol. 2004 Feb;23(2):119-25.
3) Baschat A. Doppler application in the delivery timing of the preterm growth-restricted fetus: another step in the right direction. Ultrasound Obstet Gynecol 2004;23:111-118.
4) Baschat AA, Gembruch U, Weiner CP, Harman CR. Qualitative venous Doppler waveform analysis improves prediction of critical perinatal outcomes in premature growth-restricted fetuses. Ultrasound Obstet Gynecol 2003;22:240-245.
5) Clinical Green Top Guidelines 2002. The investigation and management of the Small-for-Gestational-Age Fetus. Royal College of Obstetricians and Gynecologists.
6) Habek D, Hodek B, Herman R, Jugovic D, Cerkez Habe J, Salihagic A. Fetal biophysical profile and cerebro-umbilical ratio in assessment of perinatal outcome in growth-restricted fetuses. Fetal Diagn Ther 2003;18(1):12-6.
7) Hernandez-Andrade E et al. Uterine artery score and perinatal outcome. Ultrasound Obstet Gynecol. 2002 May;19(5):438-42.
(8) Severi FM, Bocchi C, Visentin A, Falco P, Cobellis L, Florio P, Zagonari S, Pilu G. Uterine and fetal cerebral Doppler predict the outcome of third-trimester small-for-gestational age fetuses with normal umbilical artery Doppler. Ultrasound Obstet Gynecol 2002 Mar;19(3):225-8.
(9) www.dsog.dk - guidelines.
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