Week 3- small for dates. Large for dates Flashcards
What are the reasons for having a small baby?
Pre-term delivery
Intra-uterine growth restriction
Constitutionally small- (healthy and small, nothing abnormal about it)
What weeks mean a baby is “pre-term” delivery?
24- 36+6 weeks
What is a term delivery?
37 onwards.
What things can cause pre-term births?
Commonest cause is idiopathic
Infection- typically one that causes systemic upset
Intercurrent illness e.g. pneumonia, appendicitis, pyelonephritis
Over-distension- anything that overextends the uterus can cause issues in pregnancy e.g. twin pregnancies, polyhydramnios (too much fluid).
Cervical insufficiency- the cervix didn’t hold together during pregnancy
Vascular- placental abruption.
What risk factors are there for pre-term birth?
Previous pre term birth Multiple pregnancy (twins) Uterine anomalies Extremes of age Poor socio-economic status Smoking Drugs Low BMI
When might you plan a C section in pre-term birth?
Severe pre-eclampsia, kidney disease or poor foetal development.
If premature rupture of membranes occurs, what would you do?
Speculum examination to make sure the membrane has actually ruptured and its not just incontinence/discharge.
Give steroids to mature the babies lungs. Give them erythromycin (supposedly lengthens the time from membrane rupture to delivery).
What is meant by the term ‘small for gestational age’?
Infant with a birthweight that is less than 10th centile for gestation corrected for maternal height, weight, fetal sex and birth order.
What is intra-uterine growth restriction?
Poor growth- can be due to maternal factors, fetal factors or placental factors.
What maternal factors can result in poor growth?
Lifestyle- smoking, alcohol, drugs
Height and weight
Age
Maternal disease e.g. hypertension
What fetal factors can result in poor growth?
Infection e.g. rubella, CMV, toxoplasma.
Congenital abnormalities e.g. absent kidneys
Chromosomal abnormalities e.g. downs syndrome
What placental factors can result in poor growth?
Infarcts
Abruption
Often secondary to hypertension
How can intrauterine growth restriction be classified?
As symmetrical or non-symmetrical.
Symmetrical- everything is proportionally small.
Asymmetrical- one part of the foetus is small inproportionaitely to another.
What are the antenatal/during labour risks of being growth restricted?
Risk of hypoxia or death.
What are the post natal risks of being growth restricted?
Hypoglycaemia
Effects of asphyxia (body deprived of oxygen)
Hypothermia
Polycythaemia (too many RBC’s)
Hyperbilirubinaemia (too much bilirubin- baby will be jaundiced).
Abnormal neurodevelopment
What clinical features indicate a poor growth of the foetus?
Fundal height less than expected- should be roughly same as gestation +/- 2cm.
Reduced fetal movements
Predisposing factors
How do you assess fetal wellbeing?
Assess growth- head circumference, femur length and waist circumference.
Cardiocotography
Biophysical assessment
Doppler ultrasound- specifically looking at umbilical artery , middle cerebral artery and ductus venosus.
What is a cardiocotography?
Two belts on the tummy- one picks up foetal heart on ultrasound on doppler. The other picks up contractions.
Produces two traces- top one tells you what the babies heart is doing while the bottom one tells you about contractions.
What is acceleration on cardiocotography?
What is it a sign of?
An increase in the babies heart beat above the base line rate lasting 10-15 seconds.
A healthy baby.
What is loss of baseline variability on cardiocotography?
What is it a sign of?
When there isn’t much up and down deflection on the babies heart rate (variability of less than 5 beats/minute)
Worrying sign if prolonged. However can be a result of sedative drugs.
What are late decelerations on cardiocotography?
Decelerations of the babies heart rate often after contractions. Worrying if 10-15 beats over 10-15mins.
What is meant by biophysical profile? How is it scored?
Assessing on ultrasound the following: -Movement -Tone -Fetal breathing movements -Liquor volume Scored out of 10. 8-10 is satisfactory, 4-6 repeat, 0-4 deliver.
How does loss of amniotic fluid reflect the babies health?
If good blood perfusion to the baby, the foetus will have good kidney perfusion meaning it pees a lot- increasing amniotic fluid volume. If bad perfusion, amniotic fluid will be lost.
What circulation is needed for the baby to be well perfused?
What happens if the placenta is bad?
A high flow, low resistance network.
If the placenta is bad you get narrowed vessels with high resistance, which aren’t good for allowing transfer of oxygen and nutrients.
What should a doppler ultrasound of the umbilical artery supposed to look like?
A toblerone- with peaks of chocolate but also chocolate in-between peaks.
What does absent end diastolic flow look like on doppler ultrasound of the babies umbilical artery?
Why is this?
Just triangles not connected.
This is because the resistance is too high which means no blood can get into the placenta. Sign of a poor placenta.
What does reverse diastolic flow look like? What does this mean the blood is doing?
What is the significance of this?
The peak goes on the other side of the line.
Means blood is flowing backwards.
Pre-death marker so need to get the baby out.
Why do you doppler the middle cerebral artery?
If the baby isn’t getting enough oxygen, it directs blood from the gut to the brain. Called cerebral redistribution..
Look at peak systolic flow. However does increase as pregnancy goes on.
Where does the ductus venosus go from? What does it carry?
The umbilical vein into the heart.
Oxygenated blood.
What are the causes of large for dates pregnancies?
Wrong dates Polydramnios Diabetes Multiple pregnancies Fetal Macrosomia
Why would someone have the wrong dates on their pregnancy?
Concealed pregnancy
Vulnerable women
Booked abroad
What is fetal macrosomia and how is it diagnosed?
Big baby
USS- gives estimated fetal birth weight of >90th centile
What are the risks of fetal macrosomia?
Clinician and maternal anxiety
Labour dystocia (difficult birth)
Shoulder dystocia (awkward positioning)- more in diabetes
Post-partum haemorrhage
How would you manage fetal macrosomia?
Exclude diabetes
Reassure
What is polyhydramnios?
Excess amniotic fluid
Why do people get polyhydramnios?
Maternal diabetes Fetal anomaly Monochorionic twin pregnancy Hydrops fetalis-Rh isoimmunisation, infection Idiopathic
What clinical features does polyhydramnios cause?
Abdominal discomfort
Prelabour rupture of membranes
Preterm labour
Cord collapse
How is polyhydramnios diagnosed?
Clinically diagnosed-
- large for dates
- Malpresentation
- tense shiny abdomen
- inability to feel fetal parts
Do US.
What would you find on ultrasound scan of polyhydramnios?
On ultrasound-
Amniotic fluid index (AFI)- >25
Deepest vertical pocket (DVP) ->8cm
What investigations would you do into polyhydramnios?
Oral glucose tolerance test (OGTT)
Serology- for toxoplasmosis, CMV, parvovirus
Antibody screen
Ultrasound- fetal survey.
How do you manage polyhydramnios?
Patient information- tell them about complications
Serial USS- growth, presentation,
Induction of labour- by 40 weeks
What are the risks of polyhydramnios during labour?
Cord collapse
Preterm labour
Post-partum haemorrhage
What is meant by multiple pregnancies and high order births?
Presence of more than one fetus e.g. twins, triplets etc.
Which groups of people are at risk of multiple pregnancies?
Using assisted conception e.g. IVF African race Family history Increased maternal age Increased parity More common in tall women.
What is meant by monozygotic?
Splitting of a single fertilised egg.
What is meant by dizygotic?
Fertilisation of 2 ova by 2 spermatozoa.
What is meant by chorionicity?
Whether the babies have one placenta or two.
NOTE
Monozygotic twins can have one placenta, two placenta’s
However dizygotic twins always have two placentas.
The chorion and the amnion together make up the placenta. The chorion is the red disc bit.
In days 1-3 you have dichorionic diamniotic twins.
Day 4-7 you have diamniotic, monochorionic twins
Day 8-13 you have monochorionic, mono amniotic twins.
How can you determine chorionicity?
Why is it important?
USS- can see the shape of the membrane and thickness of membrane.
Monochorionic twins are at a higher risk of pregnancy complications.
What are the symptoms of multiple pregnancies?
Exaggerated pregnancy symptoms e.g. excessive sickness
What are the signs of multiple pregnancies?
High AFP
Large dates for uterus
Multiple fetal poles
USS confirmation at 12 weeks.
What are the fetal complications of multiple pregnancies?
Higher perinatal mortality Congenital abnormalities IUD (could be single or both) Pre-term birth Growth restriction Cerebral palsy (8 x higher in twins) Twin-twin transfusion
What are the maternal complications of multiple pregnancies?
Hyperemesis gravidarum Anaemia Pre-eclampsia Antepartum haemorrhage Preterm labour C section.
How do you manage multiple pregnancies?
Consultant led care
clinic appointments are often. MC- every 2 weeks. DC- every 4 weeks
Maternal education.
What drug/supplement treatment is given antenatally to multiple pregnancy mothers?
Iron supplementation
Low dose aspirin
Folic acid
When are DCDA twins delivered?
37-38 weeks
When are MCDA twins delivered?
36 weeks
How are triplets delivered?
C section.
How are twins delivered?
If one is cephalic- try vaginal delivery
During labour, what precautions are made?
Epidural analgesia fetal monitoring: USS & FSE Syntocinon after twin 1 USS to confirm presentation Intertwin delivery time <30min Risk of PPH- active 3rd stage
What are the complications that can occur in pregnancy because of diabetes?
They all relate to poor control
Congenital anomalies- related to high HBA1C at booking
Miscarriage
Intra uterine death
What complications are common to pre-existing diabetes and gestational diabetes in pregnancy?
Pre eclampsia Polyhydramnios Macrosomia Shoulder dystocia Neonatal hypoglycaemia
What medication should be stopped in a diabetic who is pregnant?
ACE inhibitors
Cholesterol lowering agents
What medication should be given to a diabetic who is pregnant?
High dose folic acid. (3 months before conception to 12 weeks after)
Low dose aspirin
What management should diabetics have during their pregnancy?
Given medications/adjusted meds Fetal anomaly scan at 18 weeks Regular eye checks for retinopathy Consider continuous glucose monitoring Growth scans monthly from 28 weeks.
What are the risk factors for gestational diabetes mellitus?
Previous GDM Obesity BMI 30 or more Family history- 1st degree relative Ethnic variation: South Asia (India / Pakistan / Bangladesh), Middle Eastern, Black Caribbean Previous big baby Polyhydramnios Big baby – AC / EFW on USS Glycosuria (1+ on >1 occasion or >= 2+ on one occasion
What is the pathophysiology of gestational diabetes?
Placental hormones lead to a relative insulin deficiency and insulin resistance.
This leads to overgrowth of insulin sensitive tissues and macrosomia
Hypoxaemic state in utero
Short term metabolic complications
How do you screen for gestational diabetes?
Look for RFs
Previous GDM- monitor blood glucose or OGTT- in 1st trimester. If normal- repeat at 24-28 weeks.
How do you perform an oral glucose tolerance test?
Venous fasting blood glucose
75g glucose
2 hour venous glucose
Fasting it should be greater than 5.1
2 hours it should be greater than 8.5
What would you educate patients with diabetes on?
Role of diet, body weight
Risks associated with diabetes in pregnancy
Increased risk of baby obesity and diabetes in later life
