Large for Date Pregnancies Flashcards
What would be defined as large for date?
Symphyseal-fundal height >2cm for gestational age
What are some causes of large for date babies?
Wrong dates, foetal macrosomia, polyhydramnios, diabetes, multiple pregnancy
Why may someone end up with the wrong due date?
Late booker = concealed pregnancy, vulnerable women, transfer of care (e.g booked abroad)
How is foetal macrosomia diagnosed?
USS = EFW >90th centile, AC >97th centile
What are the risks associated with foetal macrosomia?
Clinician and maternal anxiety, labour dystocia, shoulder dystocia, PPH
How accurate is US at diagnosing foetal macrosomia?
Commonly overestimates EFW in comparison to actual weight = margin of error up to 10%
Gestation more accurate if <38 weeks
How is foetal macrosomia managed?
Exclude diabetes and reassure mother
Conservative, induction of labour or C-section
What are the conditions of induction of labour for foetal macrosomia?
Shouldn’t be done in absence of other indications
What is polyhydramnios?
Excess amniotic fluid = AFI >25cm and DVP >8cm
May be idiopathic
What is a maternal cause of polyhydramnios?
Diabetes
What are some foetal causes of polyhydramnios?
GI atresia, cardiac anomaly, tumour, monochorionic twin, hydrops foetalis, viral infection (CMV, erythrovirus B19)
What are the symptoms of polyhydramnios?
Abdominal discomfort, pre-labour membrane rupture, preterm labour, cord prolapse
What are the signs of polyhydramnios?
Large for date pregnancy, malpresentation, tense shiny abdomen, inability to feel foetal parts
What investigations are done for polyhydramnios?
OGTT, serology, antibody screen, US foetal survey
What is the management for polyhydramnios?
Serial USS = growth, LV, presentation
Induction of labour by 40 weeks
Wat are the risks in labour associated with polyhydramnios?
Malpresentation, cord prolapse, preterm labour, PPH
What are the risk factors for multiple pregnancy?
Assisted conception, African race, family history, increased maternal age, increased parity, taller height
What does zygosity refer to in twins?
Monozygotic = splitting of single fertilised egg (30%) Dizygotic = fertilisation of two ova by two sperm (70%)
How does zygosity influence chorionicity?
Dizygous = always dichorionic/diamniotic Monozygous = monochorionic/monoamniotic, monochorionic/diamniotic, dichorionic/diamniotic
What does chorionicity depend on?
On the time the fertilised ovum split
How does timing influence chorionicity?
DCDA = days 0-3 after fertilisation (morula) MCDA = days 4-7 after fertilisation (blastocyst) MCMA = days 8-14 after fertilisation (implanted blastocyst)
What causes conjoined twins?
Splitting of the formed embryonic disc 15+ days after fertilisation
How is chorionicity determined using US?
Shape/thickness of membrane = twin peak at 11-13+6 weeks (CRL 45-84mm), Lambda sign (triangular appearance of chorion)
What are monochorionic/monozygotic twins at higher risk of?
Complications during pregnancy = risk of cord entanglement, higher risk of foetal death
What are the symptoms and signs of multiple pregnancies?
Symptoms = exaggerated pregnancy symptoms Signs = high AFP, large for date uterus, multiple foetal poles
When would a US confirm the presence of a multiple pregnancy?
At 12 weeks gestation
Do multiple pregnancies carry higher risk during labour than singleton pregnancies?
Yes = 6x higher perinatal mortality
What are the foetal complications associated with multiple births?
Congenital abnormalities, intrauterine death, preterm birth, growth restriction, cerebra palsy, twin-to-twin transfusion syndrome
What are the maternal complications associated with multiple births?
Hyperemesis gravidarum, anaemia, pre-eclampsia, antepartum haemorrhage (abruption, placenta praevia), preterm labour, C-section
What is the antenatal management for multiple pregnancies?
Consultant-led care in twin/multiple pregnancy clinic
See MC twins every 2 weeks and DC twins every 4 weeks
What medications are given antenatally to women with multiple pregnancies?
Iron supplements, folic acid, low dose aspirin
How often are USS done for multiple pregnancies?
MC twins done weekly from 16 weeks gestation
DC twins done 4 weekly
Anomaly US done at 18-20 weeks gestation
What are the complications associated with monochorionic twins?
Single foetal death, selective growth restriction, twin anaemia-polycythaemia sequence, absent/reversed EDV, twin-to-twin transfusion syndrome
What are the features of single foetal death?
Risk to survivor of intra-uterine death (15%) or neurological abnormality
Do MRI of foetal brain 4 weeks post-IUD of co-twin
MCA PSV for foetal anaemia
What are the features of selective growth restriction?
May effect one twin or both
>20% associated with increased perinatal risks
Consider selective reduction if early onset with abnormal dopplers
What may twin anaemia-polycythaemia sequence follow?
Foetoscopic laser ablation for twin-to-twin transfusion syndrome = do MCA PSV
What is twin-to-twin transfusion syndrome?
Syndrome with AV anastomoses = donor twin perfuses recipient twin, rare after 26 weeks gestation
What would confirm the diagnosis of twin-to-twin transfusion syndrome?
Oligohydramnios-polyhydramnios
What is the treatment of twin-to-twin transfusion syndrome?
<26 weeks = foetoscopic laser ablation
>26 weeks = amnioreduction/septostomy
34-36 weeks = delivery
What is the prognosis of twin-to-twin transfusion syndrome?
Mortality of >90% if untreated
When should multiple births be delivered?
MCMA = 32-34+0 weeks DCDA = 37-38 weeks MCDA = 36+0 weeks with steroids
How should multiple births be delivered?
Triplets and MCMA twins = C-section
If one twin is cephalic then aim for vaginal delivery
What are the features of labour for a multiple birth?
Epidural analgesia
Foetal monitoring with USS and FSE
Syntocinon after first twin
USS to confirm presentation
What is the intertwin interval aimed for during a multiple birth?
Delivery time <30 mins inbetween twins
What are the complications of diabetes seen in pregnancy?
Congenital abnormalities, miscarriage, intra-uterine death, worsening of diabetic complications, pre-eclampsia, macrosomia, shoulder dystocia, neonatal hypoglycaemia
How should type 1 and 2 diabetics be counselled before pregnancy?
Avoid pregnancy is HbA1c >86 mmol/mol
Stop any embryopathic medications
High dose folic acid = 5mg
When should women with diabetes take folic acid supplement?
5mg/day from 3 months before conception to 12 weeks gestation
How are type 1 and 2 diabetics managed during pregnancy?
Low dose aspirin from 12 weeks gestation
Regular eye checks for retinopathy
Consider continuous glucose monitoring
What scans are done for type 1 and 2 diabetics during pregnancy?
Growth scans 4 weekly from 28 weeks gestation
Foetal anomaly scan at 18-20 weeks
When would you consider delivery in a woman with type 1 or 2 diabetes?
From 38 weeks onwards = may do so earlier if complications present
What are the risk factors for gestational diabetes?
Previous gestational diabetes, BMI >30, affected first degree relative, previous macrosomia, polyhydramnios, South Asian/Black Caribbean, big baby, glycosuria (+1 on >1 occasion or >= 2+ on 1 occasion)
Why can pregnancy cause diabetes?
It is diabetogenic state = placental hormones cause relative insulin resistance
What are some of the consequences of gestational diabetes?
Overgrowth of insulin sensitive tissues and macrosomia, short term metabolic complications, hypoxaemic state in utero, increased foetal risk of obesity and diabetes
How are women with previous gestational diabetes managed?
Recurrence is >50% so blood glucose monitoring or OGTT in firs trimester = repeat at 24-28 weeks if normal
When would you screen for gestational diabetes?
Do OGTT at 24-28 weeks = diagnostic if fasting glucose >= 5.1 mmol/l and 2hr glucose >= 8.5 mmol/l
Does gestational diabetes increase the risk of the mother developing type 2 diabetes?
Yes = increases risk by up to 70%
What are the glycaemic targets during pregnancy?
Do measurements at least 4 times a day
Fasting glucose = 3.5-5.5 mmol/l
1 hour glucose = <7.8 mmol/l
What are the benefits of oral hypoglycaemic agents?
Avoidance of insulin-associated hypoglycaemia
Less weight gain
Does insulin cross the placenta?
No
When would you consider delivery in a woman with gestational diabetes?
Insulin treatment = 38-39 weeks
Metformin treatment = 39-40 weeks
Managed by diet alone = 40-41 weeks
Deliver earlier if IUGR, pre-eclampsia or macrosomia
When would you do a C-section for a woman with diabetes during pregnancy?
If EFW is greater than 4.5kg
What are the risk factors for developing type 2 diabetes following gestational diabetes?
Obesity, insulin use during pregnancy, ethnic group
How are women with diabetes during pregnancy managed post-natally?
Measure fasting blood glucose 6-8 weeks postnatally
If picture of type 2 diabetes then do OGTT 6 weeks postnatally
