Pregnancy - large for dates Flashcards
Define what large for gestational age is
- A baby is classed as large for dates if USS EFW (estimated fetal weight) is >90th centile or AC (abdominal circumference) >97th centile for that gestational age
LGA is indicated if the SFH is >2cm for that gestational age
What are the causes for a baby to be large for their gestational age ?
- Wrong dates
- Fetal Macrosomia
- Polydramnios
- Diabetes
- Multiple Pregnancy
What are the reasons you might have the wrong dates for a pregnanacy causing you to percieve the pregnancy as large for gestational age ?
- Concelled pregnancy
- Vulnerable women
- Transfer of care - booked in abroad
Define what the term fetal macrosomia means
This described a baby which is constitutinally large due to familial genetics (i.e. the family just have large babies)
How is fetal macrosomia diagnosed ?
- Using ultrasound - USS EFW >90th centile or AC >97th centile
- Match these measurements against generic population based & customised growth charts (taking into account ethnicity, BMI & parity for customised ones)
What are the risk accompanied with fetal macrosomia ?
- Clinican & maternal anxiety
- Labour dystocia = obstructed labour
- Shoulder dystocia = specific cause of labour dystocia where the ant.shoulder of the infant cannot pass, it is more common with DM and fetal macrosomia
- PPH - bigger baby bigger risk of bleeding
What is the management of fetal macrosomia ?
- Exclude gestational diabetes - do a OGTT
- Reassure if DM excluded
- Desicion then needs to be made between conservative, IOL & c-section. - NICE recommends in the absence of any other indications, induction of labour should not be carried out simply because a healthcare professional suspects a baby is large for gestational age (macrosomic).
Define what polyhydraminios is
This is excess amniotic fluid
List the possible causes of polyhydraminios
Maternal - Diabetes
Fetal:
- Anomaly- GI atresia, cardiac, tumours
- Monochorionic twin pregnancy
- Hydrops fetalis – Rh isoimmunisation
- Viral infection (erythrovirus B19, Toxoplasmosis, CMV)
Idiopathic
What are the signs and symptoms of polyhydraminios ?
Symptoms:
- Abdominal discomfort
- Pre-labour rupture of membranes
- Preterm labour
- Cord prolapse
Signs:
- LFD - i.e. SFH
- Malpresentation
- Tense shiny abdomen
- Inability to feel fetal parts
How is a diagnosis of polyhydraminios confirmed ?
Ultrasound - based on the following measurements:
- Amniotic fluid index (AFI) > 25
- Deepest vertical pocket (DVP) > 8cm
When a diagnosis of polyhraminios is made what investigations should then be carried out ?
- OGTT - to check for DM
- Seriology - toxoplasmosis, CMV, Parovirus
- Antibody screen e.g. for Rh status
- USS - fetal survey assesing e.g. lips, stomach etc to look for abnormalities
What is the management of polyhydraminios ?
- Serial USS- growth, Left ventricle (LV), presentation
- IOL by 40 weeks
- Regarding labour there is a risk of malpresentation, cord prolapse, pre-term labour &PPH
Define what is meant by the term multiple pregnancy ?
This is the presence of > 1 fetus
What are the risks for having a multiple pregnancy ?
- Assisted conception
- Geography - low risk in Japan/china, high risk in Nigeria
- Fam history of them
- Increased age
- Increased parity
- Tall women
What is a multiple pregnancy classified by ?
- Zygosity
- Chorionicity
What can the zigosity of a multiple pregnancy be described as ?
Either monozygotic or dizygotic
- Monozygotic = they develop from one zygote
- Dizygotic = they develop from 2 different fertilised eggs
Note - A zygote is the union of the sperm cell and the egg cell. Also known as a fertilized ovum
What can the chroionicity of a multiple pregnancy be described as ?
Chorionicity = the number of placentae a pregnancy has i.e. 1 or 2 etc
- Dizygous - babies always have separate placentas & separate amniotic sacs (DCDA)
- Monozygous - may share or have their own separate placentas & may share or have their own amniotic sac ==> babies can be DCDA (dichorionic, diamniotic), MCDA, MCMA or conjoined
What is ultrasound used to assess in multiple pregnancies and why is this important ?
- The chorionicity & fetal sex
- It is important to assess the chorionicity because Monochorionic / monozygous twins at higher risk of pregnancy complications
What are the signs/symptoms of a multiple pregnancy ?
Symptoms:
- Exaggerated pregnancy symptoms e.g. excessive sickness/ hyperemesis gravidarum
Signs:
- High AFP (alpha fetoprotein)
- Large for dates uterus (SFH)
- Mutiple fetal poles
When and what is used to confirm a diagnosis of multiple pregnancy?
- USS at 12 weeks (determines the gestational age, chorionicity, & screens for DS)
List the fetal complications which may occur in a multiple pregnancy ?
- Higher perinatal mortality i.e. death of a fetus or neonate (6X higher than singleton)
- Congenital anomalies eg acardiac twin
- IUD ( single/both)
- Pre term birth
- Growth restriction- both /discordant
- Cerebral Palsy - (twins 8X higher, triplets 47X higher)
- Twin to twin transfusion- oligohydramnios & polyhydramnios (MC twins)
- Twin Anaemia- Polycythaemia Sequence (TAPS) (MC twins)
- Absent EDV (AEDV) or Reversed (REDV) - associated with perinatal mortality
List the maternal complications which may occur in a multiple pregnancy
- Hyperemesis Gravidarum
- Anaemia
- Pre eclampsia
- APH - abruption, placenta praevia
- Preterm Labour
- Caesarean section
List the standard antenatal management of multiple pregnancies
- Twin/mulitple pregnancy clinic
- Maternal education
- Medications - Fe supplements, aspirin, folic acid
- Anomaly US at 18-20 weeks.
- MC clinic 2 weekly and US 2 weekly from 16/40 onwards
- DC clinic 4 weekly and US 4 weekly from 16/40 onwards
What should be done if a single fetal IUD occurs during a multiple pregnancy ?
- MRI fetal brain 4 weeks post IUD of co-twin (so of the one alive)
- MCA PSV to check for fetal anaemia
If selective growth restriction is detected during a multiple pregnancy, what may be considered ?
- If early onset with abnormal dopplers consider selective reduction
- Selective reduction is the practice of reducing the number of fetuses in a multiple pregnancy, say quadruplets, to a twin or singleton pregnancy.
What is Twin Anaemia- P0lycythaemia Sequence (TAPS)?
- It is a form of twin-to-twin transfusion syndrome (TTTS)
- Results in a donor and a recipient twin, the donor twin can develop anaemia whilst the recipient twin can develop polycythaemia
What are the risk factors for developing Twin Anaemia- Polycythaemia Sequence (TAPS)?
Occurs randomly or after fetoscopic Laser ablation for TTTS
What is twin to twin transfusion syndrome (TTTS)?
- It is a syndrome where the placenta contains artery-vein anastomoses which result in a donor twin perfusing the recipient twin.
- It is Rare to occur after 26/40
What are the signs of TTTS?
- Polyhydramnios (excess amniotic fluid) in the sac of one twin
- Oligohydramnios (decreased to no amniotic fluid) in the sac of the other twin
- Size differences (discordance) in the twins
If left untreated what is the outcome of TTTS?
- Mortality >90% with no treatment
- Neurological morbidity 37% and high in surviving twin if IUD
What is the treatment of TTTS?
- Before 26/40 – Rx fetoscopic laser ablation
- >26/40- amnioreduction /septostomy
- Deliver 34-36/40
When and how should the following multiple pregnancies be birthed ?
- DCDA
- MCDA
- MCMA
- triplets or more
- Conjoined twins
- DCDA - 37 to 38 weeks
- MCDA - after 36+0 weeks with steroids
- MCMA - c-section
- Triplets or more - c-section
- Conjoined twins - MDT & specliased centres
For DCDA and MCDA - if twin one cephalic aim for vaginal delivery
Describe the management of labour of a multiple pregnancy
Labour- High Risk:
- Consultant Led Unit
- Epidural analgesia
- Fetal monitoring: USS & FSE (fetal scalp electrode)
- Syntocinon after twin 1
- USS to confirm presentation
- Intertwin delivery time <30min
- Risk of PPH- active 3rd stage
