Large For Dates Flashcards
what is large for dates?
symphyseal-fundal height >2cm above gestational age
examples of what can cause large for dates?
wrong date fetal macrosomnia polyhydramnios diabetes (can cause macrosomnia, polyhyramnias and multiple pregnancy) multiple pregnancy
what can lead to wrong dates at pregnancy booking?
late booking
- concealed pregnancy (deliberate or unaware that theyre pregnant - common in very athletic women)
- vulnerable women
- transfer of care from abroad
what is fetal macrosomnia?
big baby
EFW > 90th centile
AC > 97th centile
(generic charts not used, charts for different ethnicities etc)
risks to mother of macrosomnia?
clinical and maternal anxiety
labour dystocia
shoulder dystocia (more with diabetes)
PPH
how is macrosomnia diagnosed?
US scan
- but EFW is commonly overestimated (10% margin of error)
how is macrosomnia managed?
exclude diabetes in mother
reassure mother
conservative measures
when is a cesarian section delivery advised in macrosomnia?
> 4.5kg
25 y/o first pregnancy abdominal discomfort 28 weeks pregnant 35cm symphyseal-fundal height (SFH) what is main differential?
polyhydramnios
what is polyhydramnios?
excess amniotic fluid
amniotic fluid index >25cm
deepest pool >8cm
(can be clinical diagnosis in experienced clinician)
maternal causes of polyhydramnios?
diabetes
fetal causes of polyhydramnios?
anomaly (GI atresia, cardiac, tumours) monochorionic twin pregnancy hydrops fetalis (Rh isoimmunisation) viral infection (erythrovirus B19, toxoplasmosis, CMV) idiopathic
symptoms of polyhydramnios?
abdominal discomfort
pre-labour rupture of membranes (water breaking)
preterm labour
cord collapse
signs of polyhydramnios?
large for dates
malpresentation
tense shiny abdomen
inability to feel fetal parts
diagnosis of polyhydramnios?
US
- AFI >25
- DVP >8cm
(can be subjective)
investigations in polyhydramnios?
OGTT (exclude diabetes)
serology (toxoplasmosis, CMV, parovirus)
antibodys creen
USS (fetal survey - lips, stomach)
management of polyhydramnios?
inform patient of potential complications
serial US (growth, LV, presentation)
induce labour by 40 weeks
neonatal examination
what increases chance of multiple pregnancy?
assisted conception African race more common in nigeria family history increased maternal age increased parity more common in tall women
mono/dizygotic twins?
mono = splitting of a single fertilized egg (30%) di = fertilization of 2 ova by 2 spermatozoa (70%)
what is chorionicity and why is it important?
number of placenta (1 or 2)
dizygous = always dichorionic, diamniotic (2 placenta, 2 sacs)
monozygous = can be MC/MA, MC/DA, DC/DA, or conjoined depending in time of splitting of fertilized ovum
splitting of the fertilized ovum at which points in time create which classification of twins?
day 3 after fertilization = dichorionic, diamniotic
day 4-7 = monochorionic, diamniotic
day 8-14 = monochorionic, monoamniotic
day 15+ = conjoined twins
how is chorionicity determined?
shape and thickness of membrane on US scan (11-13+6 weeks)
- T sign = monochorionic diamniotic
- Lambda sign = dichorionic diamniotic
why is chorionicity important?
monochorionic/monozygous twins at higher risk of complications
symptoms of multiple pregnancy?
exaggerated pregnancy symptoms (e.g excessive sickness/hyperemesis gravidarum)
high AFP
large for dates
multiple fetal poles
when can multiple pregnancy be confirmed?
US scan at 12 weeks
fetal complications of multiple pregnancy?
congenital abnormalities IUD (single/both) pre-term birth growth restriction cerebral palsy twin to twin transfusion (oligohydramnios and polyhydramnios)
maternal complications of multiple pregnancy?
hyperemesis gravidarum anaemia pre-eclampsia antepartum haemorrhage (abruption, placenta praevia) preterm labour caesarean section
management of multiple pregnancy?
consultant lead care twin/multiple pregnancy clinic clinic appointments - every 2 weeks if Monochorionic - every 4 weeks if DC give maternal education
what medication can be used in multiple pregnancy?
iron supplement
low dose aspirin
folic acid
how are monochorionic twins monitored via US?
every 2 weeks from 16 weeks look for anomaly at 18-20 weeks look at deep vertical pool bladder and umbilical artery doppler EFW
complications in monochorionic twins?
single fetal death (also involves risk to surviving twin)
selective growth restriction
twin to twin transfusion syndrome (TTTS)
twin anaemia-polycythaemia sequence (TAPS)
absent EDV (AEDV) or reversed (REDV)
what is twin anaemia polycythaemia sequence?
unequal blood counts between twins in the womb (form of TTTS)
can follow fetoscopic laser ablation for TTTS?
main complications to be aware of?
twin to twin transfusion syndrome (TTTS)
what is TTTS?
syndrome with artery-vein anastamosis
donor twin perfuses the recipient twin
(rare after 26 weeks)
how is TTTS diagnosed?
oligohydramnios of one amniotic sac (low amniotic fluid) and polyhydramnios of the other (high amniotic fluid)
complications of TTTS?
mortality >90% without treatment
37% neurological morbidity
management of TTTS?
if before 26 weeks = fetoscopic laser ablation
if over 26 weeks = amnioreduction/septostomy
deliver at 34-36 weeks
risks in monochorionic monoamniotic twins?
risk for cord entanglement
higher risk of fetal death
should be delivered by C section at 32-34 weeks
types of complex multiple births?
monochorionic monoamniotic twins
conjoined twins
higher order births (trichorionic twins, monochorionic dichorionic twins)
how are multiple pregnancies delivered?
timing - DCDA = 37-38 weeks - MCDA = after 36 weeks with steroids mode of delivery - triplets or more = C/section - MCMA = C/section - twins = if twin one cephalic, aim for vaginal delivery
labour is high risk in multiple pregnancy, how is this managed?
ocnsultant lead epidural anaesthesia feal monitoring (US and FSE) syntocinon after twin 1 US to confirm presentation intertwin delivery time <30 mins risks of PPH - active 3rd stage
complications of pre-existing diabetes in pregnancy?
if pre-existing diabetes
- congenital anomalies (related to high HBA1C)
- miscarriage
- intra-uterine death
- worsening diabetes complications (retinopathy, nephropathy)
complications of gestational and pre-existing diabetes in pregnancy?
pre-eclampsia polyhydramnios macrosomnia shoulder dystocia neonatal hypoglycaemia
pre-pregnancy counselling in diabetes?
monitor HBA1C (aim for 48)
avoid pregnancy if HBA1C >86
stop any embryopathic medication (eg ACE inhibitors, cholesterols lowering drugs)
determine macrovascular and microvascular complications
high dose folic acid 5mg 3 months before and after conception
advice about diabetes and hypoglycaemia
contraception
management of diabetes in pregnancy?
early booking
5mg folic acid
low dose aspirin from 12 weeks
fetal anomaly scan at 18-20 weeks
regular eye checks for retinopathy
refer to renal team if nephropathy present
give hypoglycaemic agents (insulin MDI/pump, metformin)
consider continuous glucose monitoring
growth scans 4 weekly from 28 weeks
counsel about shoulder dystocia
deliver at 38 weeks (earlier if complications)
risk factors for gestational diabetes?
previous gestational diabetes BMI >30 family history (in 1st degree relative) south asian, middle eastern, black caribbean previous big baby polyhydramnios big baby seen on US glycosuria
pathophysiology of gestational diabetes?
pregnancy hormones cause diabetes
- placental hormones cause relative insulin deficiency/insulin resistance
consequences of gestational diabetes?
overgrowth of insulin sensitive tissues and macrosomnia
hypoxaemic state in utero
short term metabolic problems
fetal metabolic reprogramming leading to increased long term risk of obesity and diabetes
screening and diagnosis in GD?
look at risk factors at booking if previous GD - monitor BG - or OGTT 1st trimester and repeat at 24-28 weeks if normal always do OGTT at 24-28 weeks anyway
how is OGTT taken?
measure venous FBS
give 75g glucose solution
measure 2 hr venous glucose (they should have minimal physical activity between tests)
diagnostic OGTT values?
fasting = 5.1
2 hour = 8.5
(NICE is different)
glycaemic targets in diabetes?
fasting = 3.5-5.5 mmol/L
1 hr post meal = <7.8mmol/L
should measure blood glucose minimum 4 times per day (premeal/1 hr post meal/before bed)
potential advantages of oral hypoglycaemic agents?
avoidance of hypoglycaemia associated with insulin
less weight gain
less education required to ensure safe administration
timing of delivery in diabetes?
pre-existing - 38 weeks onwards - earlier if complications gestational - insulin treatment 38-39 weeks - metformin 39-40 weeks - diet alone 40-41 weeks - if fetal macrosomnia/IUGR/PET earlier delivery
mode of delivery in diabetes?
maternal preference
other indication for C/section
should discuss risks and benefits of vaginal birth (shoulder dystocia)
C/section if EFW >4.5kg
post natal period in pregnancy + diabetes?
future development of type 2 diabetes is likely
risk factors
- obesity
- use of insulin during pregnancy
- fasting glucose levels from OGTT during pregnancy can indicate risk
- IGT post partum
- ethnic group
should do fasting blood sugar 6-8 weeks after birth
do OGTT 6 weeks after birth if picture of type 2 diabetes
annual FBS and lifestyle changes
risk during labour in polyhydramnios?
malpresentation
cord prolapse
preterm labour
PPH (post partum haemorrhage)
