Large for dates Flashcards
what is large for dates
symphyseal-fundal height >2cm for gestational age
causes of large for dates
wrong dates foetal macrosomia diabetes multiple pregnancy Polyhydramnios
causes for late booking in pregnancy
concealed pregnancy
vulnerable women
transfer of care eg. booked abroad
what is foetal macrosomia
‘big baby’
USS estimated foetal weight >90th gentile
abdominal circumference >97th percentile
risks of macrosomia
clinician and maternal anxiety
labour dystocia (baby physically cant get out)
shoulder dystocia (after head gets out, the anterior shoulder gets stuck behind the pubic bone)
post partum haemorrhage
what is the margin of error for ultrasound estimated foetal weight
10%
eg. could estimate 4000g but its actually 3600g
how do you manage macrosomia
exclude diabetes
reassure
Birth plan eg. conservative vs induction of labour vs caesarean section
induction of labour should not be carried out for macrosomia unless there are other indications
what is Polyhydramnios
excess amniotic fluid
Amniotic fluid index >25cm
Deepest pool >8cm
causes of Polyhydramnios
Maternal Diabetes
Anomaly- GI atresia, cardiac, tumours
Monochorionic twin pregnancy
hydros fetalis (accumulation of fluid in the foetus)
viral infection
idiopathic
how does Polyhydramnios present
Abdominal discomfort
Pre-labour rupture of membranes
Pre-term labour
Cord prolapse
Signs: large for dates malpresentation tense shiny abdomen inability to feel fatal parts
how do you investigate Polyhydramnios
Ultrasound
Amniotic fluid index >25
Deepest vertical pocket >8cm
Survey fetus
Oral glucose tolerance test
Serology - toxoplasmosis, CMV, parvovirus
Antibody screen
how do you manage Polyhydramnios
Inform patient fo complications
Serial USS -growth, presentation
Induce labour by 40 weeks
risks in labour caused by Polyhydramnios
Malpresentation
Cord collapse
Preterm labour
Post partum haemorrhage
what is a multiple pregnancy
more than one foetus - twins, triplets etc
spontaneous twins 1/80
spontaneous triplets 1/10,000
increased with assisted conception
what increases the risk of multiple pregnancy
Assisted conception Race - African Geography - more common in Nigeria, less common in Japan and china FH Increased maternal age Increased parity (have had kids before) Tall women>short women
what are monozygotic twins
splitting of a single fertilised egg
30% of twins
what are dizygotic twins
fertilisation of 2 ova by 2 sperm
70% of twins
always dicorchionic/diamniotic
what are dichorionic twins
twins that have 2 placentas
what are monochorionic twins
twins that share a placenta
what are monoamniotic twins
twins that share 1 amniotic sac
what are diamniotic twins
twins that have their own amniotic sacs
what combinations of chronicity and amnionicity can you get
Dichorionic/diamniotic
(2 placentas, 2 amniotic sacs) - get in dizygotic twins or day 3
Monochorionic/diamnionic
(1 placenta, 2 amniotic sacs)
-monozygotic twins that split on days 4-7
Monochorionic/monoamniotic
(1 placenta, 1 amniotic sac)
-monozygotic twins that split on days 8-14
what determines chronicity/amnionicity
time of splitting off of fertilised ovum in monozygotic twins
what days do monozygotic twins split to be conjoined
days 13-15
or >day 15
monozygotic twins that split day 3
dichorionic/diamniotic
DCDA
monozygotic twins that split days 2-7
monochorionic/diamniotic
MCDA
monozygotic twins that split days 8-14
monochorionic/monoamniotic
MCMA
monozygotic twins that split >15 days
conjoined
how do you determine chorionicity
Ultrasound
-shape of membrane and thickness of membrane
Foetal sex
what type of twins are at highest risk of pregnancy complications
Monochorionic monozygous twins
ultrasound sign for DCDA twins
Lambda sign
curve in membrane as it is two separate ones coming together
ultrasound sign for MCDA twins
T sign
Thick at top = single placenta
Thin down the middle - divides the two amniotic sacs
symptoms of multiple pregnancy
Exaggerated symptoms of pregnancy eg- excessive sickness/hyperemesis gravidarum
signs of multiple pregnancy
High AFP
Large for dates uterus
Multiple foetal poles
Confirm via ultrasound at 12 weeks
Foetal complications of multiple pregnancy
Higher perinatal mortality (6x higher than singleton)
Congenital anomalies
Intrauterine death (one or both)
Preterm birth
Growth restriction (one or both)
Cerebral palsy (twins 8x higher, triplets 47x higher)
twin to twin transfusion (causes Oligohydramnios and Polyhydramnios)
Maternal complications of multiple pregnancy
Hyperemesis Gravidarum Anaemia Pre eclampsia Antepartum haemorrhage - abruption, placenta praaevia Preterm labour C-section
how often are appointments needed with a consultant for twins
Monochorionic - every 2 weeks (including USS)
dichorionic - every 4 weeks
including USS
what medications are given to mothers with multiple pregnancies
Iron supplements
Low dose aspirin
Folic acid
complications of monochorionic twins
Single foetal death
Selective growth restriction
Twin-twin transfusion syndrome
Twin anaemia
Absent EDV (end diastolic flow) or reversed end diastolic flow - sign of cardiac stress on foetus/placental insufficiency
what is twin-to-twin transfusion syndrome
Artery vein anastomoses
Donor twin perfuses recipient twin
rare after 26 weeks
causes Oligohydramnios and Polyhydramnios
complications to twin-twin transfusion syndrome
mortality >90%
neurological morbidity 37% and high in surviving twin if intrauterine death
treatment for twin-twin syndrome
<26 weeks - Fetoscopic laser ablation
> 26 weeks - Amnioreduction/septostomy
deliver 34-36 weeks
when would you deliver dichorionic diamniotic twins
37-38 weeks
twin would you deliver monochorionic monoamniotic twins
36 weeks with steroids
how do you deliver triplets or more
c-section
how do you deliver monochorionic monoamniotic twins
c-section
how do manage labour for twins
consultant led epidural fetal monitoring syntocinon after twin 1 USS to comfirm presentation Intertwin delivery time needs to be <30 mins risk of PPH
what types of diabetes do you get in pregnancy
Pregestational
type 1
type 2
MODY
Gestational
complications of pre-existing diabetes in pregnancy
Related to poor control
congenital abnormality (related to high HBA1C before booking)
Miscarriage
Intrauterine death
Worsening diabetic complications eg. retinopathy, nephropathy
complications of gestational and pre-existing diabetes in pregnancy
Pre eclampsia Polyhydramnios Macrosomnia Shoulter dystocia Neonatal hypoglycaemia
Pre-pregnancy counselling for diabetes
aim for HBA1C to be 48mmol/mol (avoid pregnancy if >86)
stop teratogens eg. ACEis
Determine macro and micro vascular complications
high dose folic acid 3 months before conception to 12th week
general diabetes advice
risk factors for gestational diabetes
Previous GDM BMI >30 FH Previous big baby Polyhydramnios Glycosuria current big baby
how is gestational diabetes caused
placental hormone cause relative insulin deficiency/insulin resistance
this leads to overgrowth of insulin sensitive tissues in the foetus - macrosomnia
hyperaemic state in utero
foetal metabolic reprogramming leading to increase in long term risk of obesity, insulin resistance and diabetes
how do you screen for gestational diabetes
oral glucose tolerance test in 1st trimester, then repeated at 24-28 weeks
diagnostic values
fasting glucose >5.1
2 hour glucose >8.5
management of gestational diabetes
diet, weight and exercise control
growth scans
use hypoglycaemic agents when diet and exercise fail to maintain targets
when do you deliver a baby if mother has pregestational diabetes
> 38 weeks
when do you deliver a baby is there is gestational diabetes
on metformin 38-39 weeks
diet alone 40-41 weeks
if fetal macrosomia earlier delivery
what is the risk of future development of type 2 diabetes if the mother has had gestational diabetes
70%
Fasting blood sugar done 6-8 weeks postnatally
