Fetal growth Flashcards
Define fetal growth
Increase in mass that occurs between end of embryonic period and birth
Simplest way of determining size of infant
Palpating maternal abdomen to find symphysis fundal height
What is symphysis fundal height
Distance between pubic bone and top of the uterus
Why is symphysis fundal height vulnerable to a variety of errors
Data can be lower than actually is due to:
Wrong last period date
Baby is lying transversely
Oligohydramnios
Data can be higher due to:
Maternal obesity
Wrong last period date
Multiple pregnancy
What is oligohydramnios
Low amniotic fluid levels
Complications assocaited with baby being larger than expected on SFH
Molar pregnamcy
Fibroids
Polyhydramnios
Large baby
What is a molar pregnancy
Formed from a previous implanted failed blastocyst that has become a mass
What 4 things are combined to guve estimated fetal weight
Biparietal diameter
Head circumfrence
Adbdominal circumfrence
Femur length
What is done with ultrasound data
The changes in each parameter are plotted and growth over time is visualised- they are expected to follow a centile showing a steady increase in growth
Why are centiles used totrack growth of fetus’
Allows compensation for different sized babies and shows their development is normal
Differences in growth velocity across term
14-15 wks= 5g/day
20wks= 10g/day
33wks= 30g/day
>34wks= growth rate drops
Characterisation of normal fetal growth
Cellular hyperplasia (increased cell numbers): 4-20 weeks Hyperplasia and hypertrophy (increased cell size): 20-28 weeks Hypertrophy dominates: 28-40 weeks
What is main key factor in fetal weight gain
Hypertrophy as most weight gain occurs in final trimester
Issue of using last menstrual period to date pregnancy
Confounding factors include irregular length of periods, endometrial bleeding that is abnormal, oral contraceptive use and breastfeeding
Also people who have had unplanned pregnancies are much less likely to be aware of their most recent period
What is best practice to date pregnancy now
Crown rump length
How does poverty affect fetal growth
Less educated about use of things such as alcohol use during pregnancy
More likely to have disease which can affect baby
More likely to have a baby at younger age
Ideal age for pregnancy for healthy fetus environment
16-35
Problem with having baby over 35
More inclined to have long pregnancy-> increased risk of death to mother and fetus
More likely to have preterm labour
Increased risk of downsyndrome
Problem with havng baby under 16
More likely to have preterm labour which can lead to neurological issues such as irritability, crying and trouble sleeping which affect coping of mother
Effects of weed use during pregnancy
Slows fetal growth Premature delivery Low birth weight Delivery complications Can lead to addiction
Effects of heroin use during pregnancy
Interrupted development Stillbirths Preamture births GI issues Large head
Effects of cocaine use during pregnancy
Smaller brain so learning issues
Stillborn
Premature
Effects of alcohol use during
Facial abnormalities
Affects brain and CNS development -> behavioural issues and retardation
Symptoms of fetal alcohol syndrome
Brain abnormalities
Cognitive deficits
Distictive facial features
Effects of nicotine use on fetal blood supply during
Nicotine constricts blood vessels reducing oxygen supply to baby-> still births
Effects of nicotine use on baby if survives
Low weight
increased asthma risk due to resp effects
Effect of low iron diet on fetus
Anaemia
Effect of low calcium diet on fetus
Poor bone and teeth develpment
Effect of low protein diet on fetus
Retardation
Smaller fetus
Effect of maternal depression on fetus
Slower fetal growth
Associated with maternal cortisol levels
Effect of gender on fetal growth
Males are bigger
Effect of previous pregnancies on fetal growth
Infants are bigger in subsequent pregnancies
Effect of insulin on fetal growth
Increases nutrient delivery and mitotic drive not the differentiation of tissue
Modulates IGF
Affects adipose tissue
Effects of cortisol on fetal growth
Tissue differentiation and maturation
How does cortsiol affect fetal growth
Directly on cells by altering transcription and post translastional modification- also may initiate switch from IGF II to IGF I
Effect of thyroxine on fetal growth
affects tissue accretion and differentiation
Effect of pituitary growth hormone on fetal growth
Very little
Difference between IGF II and I in fetal growth
II involved in embryonic develompment and I in growth of newborn
Effects of fetal glucocorticoids
Maturation of surfactant in lungs
Control of glycaemia in liver
Maturation of the expression of digestive enzymes
Proliferation of the villi
Proof growth hormone has no effect on growth in fetus
No defects present at birth of individuals with deficits
Growth factors affecting fetal growth
Epidermal growth factors
Fibroblast growth factors
Transforming growth factor
Define small for gestational age
Infant has birth weight <10th centile
Define intrauterine growth restriction
Failure for infant to achieve its predetermined genetic potential
How heavy is low birth weight
less than 2500g at delivery
How heavy is very low birth weight
less than 1500gmat delivery
How heavy is extremely low birthweight
less than 1000g at delivery
What is linked with IUGR
pre-eclampsia
What is pre-eclampsia
Diminshed re-mdelling of spiral arteries by cytotrophoblasts
What is pre-eclampsia associated with
Hypertension, proteinuria and oedema
Treatment for pre-eclampsia
Corticosteroids
Receptor for all growth factors
Tyrosine kinase linked
How are neurotransmitters inhibitted
During development cells do have muscarinic receptors on suface but ebryonic cholinesterase is very active through morphogenesis
Most common factor amongst stillbirths
IUGR
Short term complications of IUGR
Respiratory distress Intraventricular haemorrhage Sepsis Hypoglycaemia Necrotising enterocolitis Jaundice Electrolyte imbalance
Moderate term complications of IUGR
Respiratory problems
Developmental delay
Special needs schooling
Long term complications of IUGR
Fetal programming
When does most IUGR occur
Second and third trimester- this is where most growth occurs
When does pre-eclampsia tend to occur
past 20 weeks
