Large for Dates Flashcards
What does it mean if a foetus is considered “large for date”?
Symphyseal-fundal height >2cm for Gestational age
What are the possible reasons for a baby being large for date?
- Wrong dates
- Fetal Macrosomia
- Polydramnios
- Diabetes
- Multiple Pregnancy
Why may a patient have wrong dates which contribute to healthcare professionals thinking the baby is large for dates?
- Late Booker
- Concealed pregnancy (undiagnosed)
- Vulnerable women (e.g. children already in social care => not engaging with healthcare during pregnancy)
- Transfer of Care: Booked abroad
How is foetal macrosomia diagnosed?
Ultrasound Scan
- Estimated Foetal Weight >90th centile
- plotted on population based charts OR customised growth charts
How are growth charts “customised” to the mother?
Take into account:
- ethnicity (caucasian population = largest babies > african >asian)
- BMI
- parity (previous children and their birth weights)
What are the risks of foetal macrosomia?
- Labour dystocia (difficulty to progress)
- Shoulder dystocia (shoulder gets stuck - more common with diabetes)
- Post Partum Haemorrhage
How should foetal macrosomia be managed?
- Exclude diabetes
- Reassure
- Plan for Conservative Mx vs Induction of Labour vs C-Section delivery
What name is given to a condition of excess amniotic fluid which can cause a baby to be large for date?
Polyhydramnios
How is Polyhydramnios diagnosed?
Amniotic Fluid Index (AFI >25cm)
Deepest Pool >8cm
experienced clinicians may be able to diagnose this clinically
What is the most common maternal cause of polyhydramnios?
Diabetes
After diabetes, what is the next most common cause of polyhydramnios?
Idiopathic
=> no cause identified
What causes of polyhydramnios are usually due to the foetus?
- Anomaly- GI atresia, cardiac, tumours
- Monochorionic twin pregnancy
- Hydrops fetalis (abnormal fluid in>2 fetal compartment => ascites, pleural effusion, pericardial effusion, oedema)
- Viral infection (erythrovirus B19, Toxoplasmosis, CMV)
What symptoms of polyhydramnios does the mother often present with?
- Abdominal discomfort
- Pre-labour rupture of membranes
- Preterm labour
- Cord prolapse through cervix
What signs of polyhydramnios may be present on clinical examination?
- Large for date
- Malpresentation
- tense shiny abdomen
- inability to feel foetal parts on examination
How is polyhydramnios investigated?
- Oral Glucose Tolerance Test (OGTT)
- Viral Serology
- Antibody Screen
- USS – fetal survey- lips, stomach
How is polhydramnios managed?
- Serial USS for growth, presentation
- Induction of Labour by 40 weeks
What complications should you warn the patient about before labour?
- Risk malpresentation
- Risk of cord prolapse
- Risk of Preterm Labour
- Risk of Post Partum Haemorrhage
What is the incidence of spontaneous twins and triplets?
Spontaneous twins 1:80
Spontaneous triplets 1:10,000
What can increase a woman’s risk of multiple pregnancy?
- Assisted conception (less common now as only one embryo is transferred)
- Race - African
- Geography (Africa > Europe > Asia)
- Family History
- Increased maternal age
- Increased Parity (no. of children born)
- Tall women> short women
What is the difference between Gravidity and Parity?
Gravidity - number of times a woman has been pregnant
Parity - number of times a woman has given birth to a foetus with gestational age of >24 weeks
(regardless of whether born alive or still born)
What is the difference between monozygotic and dizygotic twins?
Monozygotic : splitting of a single fertilised egg (30%)
Dizygotic: fertilisation of 2 ova by 2 spermatozoa(70%)
Describe the potential chorionicity of monozygotic and dizygotic twins
Chorionicity = ONE or TWO placentas (i.e. do they share)
Dizygous
- always DCDA
- Dichorionic (2 placentas), Diamniotic (2 amniotic sacs)
Monozygous-
DCDA = Dichorionic, Diamniotic (2 placentas and 2 amniotic sacs)
MCDA = Monochorionic, Diamniotic (1 placenta, 2 amniotic sacs)
MCMA = Monochorionic, Monoamioniotic (shared placenta and amniotic sac)
Conjoined
What factor can change the chorionicity of monozygotic twins?
Depends on time of splitting of fertilised ovum
- later splitting = sharing of more structures (up to conjoinment)
What days of gestation can the fertilised egg split and change the chorionicity of monozygotic twins?
Day 1-3 = DCDA
Day 4-8 = MCDA
Day 8-13 = MCMA
Day 13-15 = Conjoined
How can the chorionicity be determined on an US scan?
- Assessing shape/thickness of membrane
- Lambda sign = DCDA
- T shape = MCDA
- foetal sex may give indication (if opposite sexes => Dizygotic => DCDA)
What symptoms experienced by the pregnant mother may indicate a multiple pregnancy?
Exaggerated pregnancy symptoms
e.g. excessive sickness/ hyperemesis gravidarum
What signs may point towards a potential multiple pregnancy?
- High AFP
- Large for dates uterus
- Mutiple fetal poles
- USS confirmation at 12 weeks
What complications can present in a multiple pregnancy?
- Higher perinatal mortality
- Congenital anomalies
- IUD (single twin/both)
- Preterm birth
- Growth restriction- both /discordant
- Cerebral Palsy
- Twin to twin transfusion
What are the maternal complications of multiple pregnancy?
- Hyperemesis Gravidarum
- Anaemia (as BOTH babies need lots of iron)
- Pre eclampsia
- Antepartum haemorrhage- abruption, placenta praevia
- Preterm Labour
- C section
How are pregnant mothers with multiple pregnancy managed antenatally?
- Consultant Led care
- Attend Twin/Multiple Pregnancy Clinic
Appointments:
=>MC: every 2 weeks
=> DC every 4 weeks - Maternal education and Support (e.g. schemes to give discounts on baby food/clothes)
What medication should mothers of multiple pregnancy be started on?
- Iron supplementation
- Low Dose Aspirin
- Folic Acid
How often do mothers of multiple pregnancy require Ultrasound scanning?
- MC 2 weekly from 16/40
- DC 4 weekly
Anomaly USS 18-20 weeks
What are the main complications of monochorionic twins?
- Single Fetal Death (also causes risk to survivor => neuro abnormality)
- Selective Growth Restriction (sGR)
- Twin-To- Twin Transfusion Syndrome (TTTS)
What do twins look like after being born with Twin-To- Twin Transfusion Syndrome (TTTS)?
- one = small and pale
- other = polycythaemic and larger
due to one being donor and one being receiver twin`
What other complications does Twin Transfusion Syndrome (TTTS) cause?
Oligohydramnios- polyhydramnios (Oly-Poly)
- One twin with oligo, other with polyhydramnios
HOw can Twin Transfusion Syndrome (TTTS) be treated?
Before 26/40 RARE – Mx = Foetoscopic laser ablation
> 26/40- amnioreduction /septostomy
Deliver 34-36/40 wks
What risks are present in an MCMA birth and how are these babies deliveres as a result?
- Risk for cord entanglement
- Higher Risk of Foetal Death
=> Deliver by C/Section 32-34 weeks
When are DCDA and MCDA twins typically delivered?
DCDA Twins deliver 37-38 weeks
MCDA Twins deliver after 36 weeks with steroids.
HOw should twins or multiple pregnancies usually be delivered?
- Triplets or more – Caesarean section
- MCMA- Caesarean section as highest risk
- If first twin presents cephalic => aim for vaginal delivery
(if second then presents breech might actually still be possible for vaginal birth after first one)
What types of diabetes must we be aware of during pregnancy?
Pregestational - Type 1,2, MODY
Gestational diabetes
What is common to all complications from diabetes which occur in pregnancy?
- they all occur due to poor glycaemic control and high HbA1c levels
What complications are specific to pre-existing diabetes?
Congenital anomalies- due to high HBA1C at booking
Miscarriage
Intra-uterine death
What complications of diabetes in pregnancy is common to both pre-existing and gestational?
- Pre eclampsia
- Polyhydramnios
- Macrosomia
- Shoulder dystocia
- Neonatal hypoglycaemia
What counselling and advice should be given to women with pre-existing diabetes who are pregnant or considering getting pregnant?
- HbA1c Monitoring Aim = 48mmol/mol (6.5%)
- Avoid pregnancy HBA1C >86 mmol/mol (10%)
- Stop diabetic medication that may harm foetus eg ACEi, cholesterol lowering
- Determine macro/ microvascular complications
- High Dose Folic Acid 5mg
- Advice about DKA/hypo (e.g. during morning sickness)
- Contraception
How should women with diabetes in pregnancy be managed and followed up?
- Low Dose Aspirin from 12 weeks
- Foetal anomaly scan (18-20 wks)
- Eye checks for retinopathy
- Check for nephropathy- refer to renal
- Hypoglycaemic Agents (insulin or metformin)
- Continuous glucose monitoring (Libre)
- Growth scans 4 wkly from 28 weeks
- Counsel about shoulder dystocia
- Deliver at 38 weeks
What are the main risk factors for gestational diabetes?
- Previous GDM
- Obesity BMI >30
- FHx: 1st degree relative
- Ethnic variation
- Previous big baby
- Polyhydramnios
- Glycosuria
HOw is gestational diabetes screened for and diagnosed?
OGTT in 1st Trimester at booking appointment
- If patient is deemed high risk, but OGTT is normal in 2st trimester, then repeat at 24-28 weeks
What values on an OGTT would indicate a diagnosis of gestational diabetes?
Fasting >=5.1 mmol/l
2 hour >=8.5 mmol/l
How is an OGTT carried out?
Venous Fasting Blood Sugar ↓ 75 g glucose given to patient ↓ 2hr venous glucose taken
Who is involved in the antenatal care of mothers with diabetes in pregnancy?
Obstetrician Endocrinologist Midwife Diabetic Specialist Nurse Dietician
What should a pregnant mother with diabetes be educated on?
- diet, body weight and exercise
- Importance of glycaemic control
- Risks: macrosomia and neonatal hypoglycaemia
- Increased risk of baby having obesity/diabetes in later life
- Increased risk of T2DM for mother
How often should pregnant mothers with diabetes check their blood sugar throughout the day?
Minimum 4 times a day- premeals
(sometimes 1 hr postmeal ) and before bed.
What are the glycaemic targets for glucose monitoring during pregnancy?
Fasting = 3.5 -5.5 mmol/l
1 hr after meal <7.8mmol/l
How should diabetic pregnant women be managed?
- Diet and Exercise
- Monitor for Pre-eclampsia
- Growth scans
- Consider Hypoglycaemic agents if diet/exercise fail to maintain targets and macrosomia is visible on US
What are the benefits of oral hypoglycaemic agents as opposed to insulin?
- Avoidance of hypo associated with insulin
- Less weight gain
- Less ‘education’ required to ensure safe / effective administration
Insulin does NOT cross the placenta. TRUE/FALSE?
TRUE
When should babies be delivered if their mother has pre-existing diabetes VS gestational diabetes?
Pregestational Diabetes:
38 weeks onwards
Gestational:
On Insulin = 38 weeks
On Metformin = 39- 40 weeks
Diet alone = 40 to 41 weeks
An Estimated foetal weight over what would indicate the need for a C-section?
If EFW >4.5kg- c/section
What are the main risk factors for the development of Type 2 Diabetes in the post-natal period?
- Obesity
- Use of insulin during pregnancy
- Insufficient Glandular Tissue post partum (low/no milk)
- Ethnic group
