Fetal Growth and Compromise Flashcards
Definition of Small for Dates (SFD)
Weight of fetus is <10th centile for gestation
At term <2.7kg
Mostly constitutionally small and have grown consistently
Assessment of fetal weight is better identoified at IUGR by looking along projected growth for that individual rather than population
Also called small for gestation age (SGA)
Definition of IUGR
Fetus has failed to reach its own growth potential
Growth in utero is small and may end up “small for dates”
A proportion will not appear SFD but will be IUGR as smaller than predicted wieght
Definition of Fetal Distress
Refers to acute situation which may result in fetal damage or death if not reversed or if the fetus is not delivered immediately
Definition of Fetal Compromise
Chronic situation defined by sup-optimal conditions for normal gorwth and neurodevelopment
Most cases involve poor nutrient transfer through the placenta (placental dysfunction)
May be with or without IUGR
e.g. in in maternal DM or prolonged pregnancy
Factors to Identify High-Risk Pregnancy
Pre-Pregnancy Factors Poor Past Obstetric Hx / previous very small baby Maternal disease Assisted conception Extremes of reproductive age Heavy smoking or durg abuse
During Pregnancy HTN Porteinuria Vaginal bleeding SFD Prolonged pregnancy Multiple pregnancy
Investigations available for monitoring fetal well-being
Cervical scan at 23 weeks
USS for fetal growth and abnormalities
USS assessment of biophysical profile and amniotic fluid volume
Limb movement, tone, breathing movements, liquor volume all scored/8
Uterine artery Doppler
Should have low resistance
Abnormal waveform at 23 weeks suggest failure low resistance
Identifies pregnancies at risk of adverse neonatal outcome in the early third trimester
PET, IUGR, abruption
MCA Doppler (Fetal circulation Doppler)
Flow increased in anaemia
Disparity between MCA flow and thoracic aorta –> head-sparing effect (indicative of fetal compromise)
Ductous venous waveform used in place of CTG
Maternal blood tests
PAPP-A –> placental hormone
Chromosomal abnormalities –> reduced in 1st trimester
Reduced levels indicative of high risk –> IUGR, placental abruption and stillbirth
CTG
Kick Chart
Record number of kicks felt
Pathological Determinents of Small for Dates
Pre-existing maternal disease e.g. renal and autoimmune disease
Pregnancy complications e.g. PET
Multiple pregnancy
Smoking
Drug use
Infections e.g. CMV
Extreme malnutrition
Congenital abnormalities
Maternal obesity
Male gender
Complications of SFD and IUGR
Stillbirth
Cerebral palsy
Preterm delivery
Increased maternal risks
Increased cesarean risk
Investigations and Diagnosis of IUGR
Examination
Serial measurements of Sacral-fundal height
Reduced or slowing
BP and urine checked –> PET associated with IUGR
Invx USS Umbilical artery Doppler Amniotic fluid volume MCA Doppler TEst for infection e.g. CMV Chromosomal abnormalities CTG
*History of reduced fetal movements not helpful
Management of IUGR and SFD
SFD Only
Growth rechecked with USS at two weekly intervals
No need for intervention if consistently growing along same projection with normal umbilical artery Doppler
IUGR at Term
Small for dates + abnormal Doppler –> deliver >36 weeks
Can be IOL of C-section
IUGR Preterm
Prevent in utero demise and neurological damage associated with placental dysfunction
Maximise gestation to avoid problems of prematurity
IUGR with abnormal Doppler –> review 2x/week
Absent EDF –> admit, steroids and daily CTG
>34 weeks –> deliver
Delay delivery until CTG or fetal Dopplers abnormal if <34 weeks
Severe IUGR –> Emergency C-Section
Definition of Prolonged Pregnancy
> / 42 weeks gestation
Complications of Prolonged Pregnancy
Increased risk of stillbirth
Neonatal illness and encephalopathy, meconium passage and fetal distress more common
Greater risk in South Asian women
Management of Prolonged Pregnancy
IOL
Failed induction of labour may lead to C-section
Increased risk of fetal distress, therefore increased risk of C-section (two fold due to indication of C-section for failed labour also)
41-42 weeks –> IOL
Associated with lower rates of C-section
Prevents 1 fetal death for every 500 women induced 41-42 weeks
If nullip with infavourable cervix –> daily CTG
Sweeping cervix 40-41 weeks can help spontaneous labour
