fetal problems Flashcards
what is the leading cause of perinatal mortality and morbidity?
prematurity
what defines prematurity?
birth <37 + 6 weeks gestation
what are the reasons for elective premature delivery?
cervical incompetence APH amnionitis pyelonephritis diabetes polyhydramnios uterine abnormalities
what is a breech presentation?
this is when the fetal legs/bum is the presenting part
what are the types of breech position?
complete = bum is presenting and fetal legs are crossed (hips and knees flexed)
Frank = bum is presenting, hips flexed and knees extended, with legs in the air
footling = one leg up/crossed and one leg dangling down as the presenting part
which is the most common type of breech position?
frank
what are the uterine risk factors contributing to breech position?
multiparity
uterine septate/ malformations
uterine fibroids
placenta praevia
what are the fetal factors that contribute to breech position?
prematurity polyhydramnios macrosomia abnormalities e.g. ancephaly twins
what are the clinical features of breech lie in pregnancy? (
on abdominal palpation - feel fetal head higher up and irregular mass in pelvis.
fetal HR auscultated higher than normal
during deliver may notice signs of fetal distress e.g. meconium stained liquor
on vaginal examination, may feel scrotum/foot as presenting part
define an oblique lie
diagonal lie with head in one of the iliac fossas
define a transverse lie
across the uterus - shoulder is presenting part
define an unstable lie
fetal position changes from day to day
what type of fetal lie is the main risk for cord prolapse?
transverse
how is the lie of the baby confirmed?
USS
when should we start to consider management for breech babies?(weeks of gestation?
before 32-35 weeks it is not significant because most likely it will spontaneously correct itself and revert by term.
how is an abnormal lie of the fetus managed?
external cephalic version
how is an abnormal lie of the fetus managed?
external cephalic version
C section - if above is contraindicated, this is advised
vaginal breech birth
what are the complications of breech presentation?
associated with mortality and morbidity due to
major complication is cord prolapse asphyxia - secondary to delay in delvery prematurity congenital malformations fetal head entrapment premature rupture of membranes intracranial haemorrhage- due to head compression during delivery
what is ECV?
The manipulation of fetus within the uterus to a cephalic presentation through maternal abdomen.
what are the complications of ECV?
fetal bradycardia/ changes to heart rate - normally revert after
Also placental abruption
who is ECV more likely to work in?
multiparous women
polyhydramnios
when is ECV contraindicated?
placenta praevia previous C section uterine abnormalities ruptured membranes those with recent APH
when is a vaginal breech delivery contraindicated?
footling position - foot can slip through a non fully dilated cervix and head and shoulders can become trapped
how is a breech vaginal delivery performed?
Can deliver via the vagina but should not apply traction as this can lead to fetal head becoming trapped
if needed special manoeuvres can be performed
what special manoeuvres can be used to deliver breech babies?
Flexing fetal knees to enable delivery of legs
Lovsett’s manoeuvre = rotate body to deliver shoulders
Mauriceau Smellie veit manoeuvre - deliver head by flexion
what defines oligohydramnios?
amniotic fluid index below 5th centile for that gestational age
describe the normal changes to the level of amniotic fluid.
normally amniotic fluid slowly rises until 33 weeks gestations, then stays level till 38 weeks and then slowly declines. By term there is around 500ml of fluid
what is amniotic fluid comprised of?
usually comprised of fetal urine output
but also some placental productions and some fetal secretions (respirations)
what is the function of the amniotic fluid?
Amniotic fluid is swallowed/ breathed in by fetus to allow development of lungs, gut, kidneys etc.
the kidneys filter and then the fetus urinates the amniotic fluid and cycle continues.
allows fetal movements - exercise
what is the pathophysiology behind oligohydramnios?
If there is a disruption in the pathway by which amniotic fluid is continually being recycled then there can be oligohydramnios
e.g. renal agenesis - bilateral in potters syndrome
bilateral multicystic dysplastic kidneys
obstructive uropathy
genetic chromosomal abnormalities
placental insufficiency - the blood is directed to fetal head and kidneys are underperfused and thus are less functional - poor urine output
rupture of membranes and leak of amniotic fluid can contribute
viral infections can cause poly or oligohydramnios
how is oligohydramnios diagnosed?
USS:
- amniotic fluid index
- maximal pool depth
- USS can assess for any structural abnormalities e.g. renal agenesis, obstructive uropathy
- fetal size - small babies may indicate placental insufficiency
in history ask if they have noticed leaks - feeling damp all the time
examination - measure symphysis fundal height, speculum examination
bedside test - IGFBP1 in vagina = if this is detected in vagina it is highly suggestive of membrane rupture because found in amniotic fluid
what is the amniotic fluid index?
what is the maximal pool depth
amniotic fluid index - measure cord free vertical pocket of fluid in 4 quadrants and add them
maximal pool depth - measure vertical height of fluid in one area
how is oligohydramnios managed?
If it is caused by ruptured membranes (PROM) - manage as you would manage PROM (induction, wait, steroids)
if there is sign of placental insufficiency, need to time delivery such that it is optimised. usually delivered before 36-37 weeks. Placental insufficiency can be measured using fetal growth rate, umbilical artery and middle cerebral artery doppler scans and CTG to find out how insufficient it is and whether we should delvier
can consider amnioinfusion
in which trimester does oligohydramnios carry a poor prognosis?
T2 - more associated with PROM and prematurity and thus lung hypoplasia and fetal respiratory distress
what is the overall prognosis / problem with oligohydramnios ?
if associated with placental insufficiency - preterm and problems associated
low amniotic fluid means fetal movements cant be practiced in utero and thus no exercise, fetus can develop severe muscle contractures which can lead to disability (despite physio)
define polyhydramnios
amniotic fluid index >95th centile for that gestational age
what is the aetiology behind polyhydramnios?
any problems with recycling of amniotic fluid allows it to build up:
- oesophageal atresis, duodenal atresia - diaphragmatic hernia (compression of oesophagus) - muscular dystrophies and CNS abnormalities
fetal hydrops
fetal anaemia
twin twin transfusion syndrome
maternal diabetes
maternal ingestion of lithium - can give fetal diabetes insipidus
increased lung secretions - cystic adenomatoid malformation of lung
macrosomia - large babies produce more
other genetic/ chromosomal abnormalities
some viral infections can cause it
how does duodenal atresia present on USS
double bubble sign
how is polyhydramnios diagnosed?
examination - does uterus feel tense USS - amniotic fluid index / maximal pool depth - fetal size - signs of fetal anatomy abnormality - detect fetal anaemia?
maternal glucose tolerance test
karyotype
check for viral infection - TORCH screen
what does TORCH stand for?
toxoplasmosis other (parvovirus) Rubella CMV Hepatitis
how is polyhydramnios managed?
no medical intervention usually required
if maternal symptoms e.g. breathlessness then amnioreduction can be considered
indomethacin (NSAID) can be used to enhance water retention and thus reduce fetal urine output
if not sure why polyhydramnios, may want to pass NGT into baby before feeding (after delivery) to ensure no atresia
what are the problems of amnioreduction
infection placental abruption (due to sudden drop in pressure)
what is the problem of giving indomethacin to treat polyhydramnios
indomethacin can close ductus arteriosus and thus should not be used after 32 weeks
what are the problems associated with polyhydramnios?
can be associated with congenital malformation
preterm - due to over extended uterus
mal presentation - fetus has room to move
more likely to have PPH because uterus has to contract more to stop bleed
what is meant by fetal compromise? what is the pathogenesis behind this?
Inadequate delivery of nutrients/ oxygen to fetus
usually due to uteroplacental insufficiency:
- increased uteroplacental vascular resistance
- intrauterine sepsis
- reduced uterine perfusion
- cord compressed
can also be due to reduced fetal reserves (glycogen storage disease)
how does fetal compromise present?
reduced fetal movements
slowing of the symphysis -fundal height measurements
how can we investigate fetal compromise?
USS:
- changes that reflect increased placental vascular resistance
- reduced resistance of middle cerebral artery suggest that this has occurred to maintain flow due to impaired placental function
- amniotic fluid index - polyhydramnios and oligohydramnios are associated with fetal compromise
CTG
if CTG abnormal - fetal scalp blood sample for lactate and degree of hypoxia
what is the biophysical profile?
a score given based on amniotic fluid, CTG and fetal behaviour to measure fetal compromise
what are the risk factors for fetal compromise?
previous IUGR, intrauterine death,
maternal Obesity, HTN, smoking, diabetes , other chronic disease, age >35
prolonged pregnancy
rhesus sensitisation
poly/oligohydramnios
how is fetal compromise managed?
depends on cause
need to weigh up risk of intrauterine hypoxia with prematurity and depending on this may want to induce labour or have a C section
continue to monitor for signs of fetal distress
sometimes amnioinfusion can be considered (if oligohydramnios or cord prolapse) - amniotic fluid infused into uterine cavity
what are the risks of amnioinfusion
amniotic fluid embolism
cord prolapse
uterine scar rupture
what is the fetus at risk at when distressed?
meconium aspiration
what is the average baby weight at birth?
7 pounds
what are the causes of large for gestational age?
maternal diabetes - main cause
- mum has high glucose that goes to baby, baby produces excess insulin which is anabolic
other cause of hyperinsulinaemia
genetic cause
beckwedth Weideman syndrome
how is large for gestational age diagnosed?
USS - symphysis fundal heights and growth scans
why is large for gestational age a problem?
injury: shoulder dystocia, brachial plexus, clavical fracture
prolonged labour
more prone to immature suckling/ feeding
risk of hypoglycaemia
risk of prolonged jaundice (due to polycythemia)
increased risk of respiratory distress syndrome
risk of left colon syndrome - temporary bowel obstruction that is self limiting but mimics Hirschsprung’s disease
how can we treat large for gestational age?
offer elective C section
criteria:
- diabetes + >4.5kg
- no diabetes + >5kg
how is small for gestational age defined?
birth weight <10th centile
severe if below 3rd centile
what are the two different types of small for gestational age?
symmetrical - small head circumference and body
asymmetrical - head circumference is normal
what is the mechanisms for small for gestational age?
intrauterine growth restriction non-placental mediated growth restriction - chromosomal - inborn errors of metabolism - fetal infection
what are the low risk factors for being small for gestational age?
age >35
BMI <20 or >25
smoking
pregnancy interval <6 months or >60 months
what are the high risk factors for being small for gestational age?
age >40, heavy smoker >11/day cocaine use excessive exercise previous small baby previous still birth chronic HTN/ pre-eclampsia diabetes with vascular disease renal impairment antiphospholipid syndrome low PAPPA
others - asthma, anaemia, infection
how is small for gestational age diagnosed?
USS:
- symphysis- fundal height
- the above can prompt growth scan (head circumference, abdominal circumference, femur length, umbilical cord blood flow
oligohydramnios and poor fetal movements can indicate placental insufficiency
may want to karyotype/ infection screen
what are the immediate complications of small for gestational age?
hypoxia
prolonged jaundice due to more RBC due to hypoxia
risk of hypoglycaemia (reduced stores) - feed within 2 hours of birth and monitor glucose
thermoregulation problem - may need incubator
what are the late complications of small for gestational age?
coronary artery disease
autoimmune thyroid
HTN
T2D
how do you manage small for gestational age?
depends on cause
- placental insufficiency - may consider delivery due to compromise in utero
- aspirin if at risk of pre-eclampsia or evidence of poor umbilical blood flow
- progesterone to prevent pre-term birth
those at risk have serial USS
smoking cessation interventions
