Intrauterine Growth Restriction Flashcards
What is the definition of SGA?
Infant has Birth weight < 10th centile
What is FGR?
Failure of the foetus to achieve predetermined growth potential for various reasons
What is the definition of Low Birthweight?
Less than 2500 g at delivery
What is the definition of very low birthweight?
Less than 1500g at delivery
What is the definition of extremely low birthweight?
Less than 1000g at delivery
Which centile for IUGR is the most sensitive?
10th centile
Will capture all babies with IUGR, but will also include those babies that are just SGA
*False positives
Which centile for IUGR is most specific?
3rd centile
All babies in 3rd centile have IUGR, but some IUGR babies may be missed
* False negatives
What are the short term problems of LBW/ FGR/ Pre-maturity?
Respiratory distress Intraventricular haemorrhage Sepsis Hypoglycaemia Necrotising enterocolitis Jaundice Electrolyte imbalance
What are the medium term problems of LBW/FGR/ Prematurity?
Respiratory problems
Developmental delay
Special needs schooling
What are the long term problems of LBW/ FGR/ Prematurity?
Fetal programming
What are the maternal medical factors linked to IUGR, SGA?
Chronic hypertension Connective tissue disease Severe chronic infection Diabetes mellitus Anaemia Uterine abnormalities Maternal malignancy Pre-eclampsia Thrombophilic defects
What are the maternal behavioural factors linked to IUGR, SGA?
Smoking Low booking weight (<50kg) Poor nutrition Age <16/ >35 at delivery Alcohol Drugs High altitude Social deprivation
What are the fetal factors linked to IUGR, SGA?
Multiple pregnancy Structural abnormality Chromosomal abnormalities Intrauterine (congenital) infection Inborn errors of metabolism
What are the placental factors linked to IUGR, SGA?
Impaired trophoblast invasion Partial abruption or infarction Chorioamnionitis Placental cysts Placenta praevia
When is the period of placentation?
10-12 weeks
What is the definition of pre-eclampsia?
Multisystem disease that usually manifests as hypertension and proteinuria
- Gestational hypertension of at least 140/90 mmHg on 2 separate occasions >4hrs apart
- Proteinuria >0.3g/day (PCR>30)
- arising de novo after the 20th week of gestation in a previously normotensive woman and resolving completely by 6th postpartum week
Which foetuses would require growth monitoring?
Indication: Bad obstetric history
- Bad obstetric history Previous maternal hypertension Previous FGR Stillbirth Placental abruption
Which foetuses would require growth monitoring?
Indication: Concerns in index pregnancy
Abnormal serum biochemistry (PAPP-A<0.3 MoM)
Reduced symphysis fundal height
Maternal systemic disease (e.g. hypertension, renal, coagulation, PET)
Antepartum haemorrhage
Multiple pregnancy
What maternal history would predispose to FGR?
Poor obstetric history Primips Obese Afro-carribean/ African Strong family history Essential hypertension Diabetes Systemic vascular disease Renal disease Thrombophilias
Describe how screening of “at risk” pregnancies at 24 weeks is done?
Uterine artery Doppler during 1st/2nd trimester
Identify high resistance flow
What is the sequence of events in FGR?
i. Increased Uterine Artery PI
ii. Increased Umbilical artery PI (reduced liquor volume)
iii. Decreased Middle Cerebral Artery PI (reduced Fetal movement)
iv. Increased Ductus Venosus PI
v. IUD
What is Pulsatility Index?
Pulsatility index is another parameter used to assess pulsatility and is defined as the difference between maximum and minimum blood flow velocity, normalized to the average velocity.
When using Doppler US, when does increased impedence in umbilical arteries become evident?
When at least 60% of placental vascular bed is obliterated
Where is the cardiac output in foetus redistributed to under hypoxia?
Increased flow: - Brain - Heart - Adrenals Decreased flow: - Lungs - Kidneys - Gut
What are the CNS effects on foetus during hypoxia?
- Poor tone
- Altered breathing
- Altered movement patterns
- Changes in heart rate patterns
When 60-70% of placental vascular tree is not functioning, what follows?
Decrease in impedance to blood flow in the middle cerebral artery as a consequence of “brain sparing effect”, while resistance increases in aortic blood flow.
The redistribution of the blood flow allows preferential oxygenation of fetal vital organs
What are the 3 shunts in fetal circulatory system?
- Ductus venosus (shunts oxygenated blood from placenta away from semifunctional liver and towards the heart)
- Foramen Ovale (shunt between atriums)
- Ductus arteriosus (aorta and pulmonary artery, shunt blood away from lungs)
Which ventricle is dominant in fetal?
Right ventricle
What is used to quantitatively assess fetal movement countings?
Cardiff kick chart (UK)
Mothers record the time taken each day to feel 10 fetal movements
What should be done if a reduction in fetal movements is reported?
Cardiotocography (CTG)
Ultrasound assessment
What are the 3 general principles of management of FGR pregnancies?
a. Problems in index preganacy
b. Screening of “at risk” pregnancies
c. Delivery
a. Manage according to serial fetal biometry, fetal Doppler, Biophysical profile and CTG
b. 24/40 wks Ut A screening
c. Aim to deliver when >28 weeks and/or >500g
Caesarean section for compromised foetuses
What can be administered to mother at gestations <36 weeks in order to improve neonatal wellbeing?
Corticosteroids
Is preeclampsia highly correlated to early or late IUGR?
Early
Is early or late IUGR more common?
Late
