Pregnancy - large for dates

Question 1

Define what large for gestational age is

Answer 1

• 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

Question 2

What are the causes for a baby to be large for their gestational age ?

Answer 2

• Wrong dates
• Fetal Macrosomia
• Polydramnios
• Diabetes
• Multiple Pregnancy

Question 3

What are the reasons you might have the wrong dates for a pregnanacy causing you to percieve the pregnancy as large for gestational age ?

Answer 3

• Concelled pregnancy
• Vulnerable women
• Transfer of care - booked in abroad

Question 4

Define what the term fetal macrosomia means

Answer 4

This described a baby which is constitutinally large due to familial genetics (i.e. the family just have large babies)

Question 5

How is fetal macrosomia diagnosed ?

Answer 5

• 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)

Question 6

What are the risk accompanied with fetal macrosomia ?

Answer 6

• 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

Question 7

What is the management of fetal macrosomia ?

Answer 7

• 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).

Question 8

Define what polyhydraminios is

Answer 8

This is excess amniotic fluid

Question 9

List the possible causes of polyhydraminios

Answer 9

Maternal - Diabetes

Fetal:

• Anomaly- GI atresia, cardiac, tumours
• Monochorionic twin pregnancy
• Hydrops fetalis – Rh isoimmunisation
• Viral infection (erythrovirus B19, Toxoplasmosis, CMV)

Idiopathic

Question 10

What are the signs and symptoms of polyhydraminios ?

Answer 10

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

Question 11

How is a diagnosis of polyhydraminios confirmed ?

Answer 11

Ultrasound - based on the following measurements:

• Amniotic fluid index (AFI) > 25
• Deepest vertical pocket (DVP) > 8cm

Question 12

When a diagnosis of polyhraminios is made what investigations should then be carried out ?

Answer 12

• 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

Question 13

What is the management of polyhydraminios ?

Answer 13

• 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

Question 14

Define what is meant by the term multiple pregnancy ?

Answer 14

This is the presence of > 1 fetus

Question 15

What are the risks for having a multiple pregnancy ?

Answer 15

• Assisted conception
• Geography - low risk in Japan/china, high risk in Nigeria
• Fam history of them
• Increased age
• Increased parity
• Tall women

Question 16

What is a multiple pregnancy classified by ?

Answer 16

1. Zygosity
2. Chorionicity

Question 17

What can the zigosity of a multiple pregnancy be described as ?

Answer 17

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

Question 18

What can the chroionicity of a multiple pregnancy be described as ?

Answer 18

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

Question 19

What is ultrasound used to assess in multiple pregnancies and why is this important ?

Answer 19

• The chorionicity & fetal sex
• It is important to assess the chorionicity because Monochorionic / monozygous twins at higher risk of pregnancy complications

Question 20

What are the signs/symptoms of a multiple pregnancy ?

Answer 20

Symptoms:

• Exaggerated pregnancy symptoms e.g. excessive sickness/ hyperemesis gravidarum

Signs:

• High AFP (alpha fetoprotein)
• Large for dates uterus (SFH)
• Mutiple fetal poles

Question 21

When and what is used to confirm a diagnosis of multiple pregnancy?

Answer 21

• USS at 12 weeks (determines the gestational age, chorionicity, & screens for DS)

Question 22

List the fetal complications which may occur in a multiple pregnancy ?

Answer 22

• 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

Question 23

List the maternal complications which may occur in a multiple pregnancy

Answer 23

• Hyperemesis Gravidarum
• Anaemia
• Pre eclampsia
• APH - abruption, placenta praevia
• Preterm Labour
• Caesarean section

Question 24

List the standard antenatal management of multiple pregnancies

Answer 24

• 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

Question 25

What should be done if a single fetal IUD occurs during a multiple pregnancy ?

Answer 25

* MRI fetal brain 4 weeks post IUD of co-twin (so of the one alive) * MCA PSV to check for fetal anaemia

Question 26

If selective growth restriction is detected during a multiple pregnancy, what may be considered ?

Answer 26

* 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.

Question 27

What is Twin Anaemia- P0lycythaemia Sequence (TAPS)?

Answer 27

* 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

Question 28

What are the risk factors for developing Twin Anaemia- Polycythaemia Sequence (TAPS)?

Answer 28

Occurs randomly or after fetoscopic Laser ablation for TTTS

Question 29

What is twin to twin transfusion syndrome (TTTS)?

Answer 29

* 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

Question 30

What are the signs of TTTS?

Answer 30

* **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

Question 31

If left untreated what is the outcome of TTTS?

Answer 31

* Mortality \>90% with no treatment * Neurological morbidity 37% and high in surviving twin if IUD

Question 32

What is the treatment of TTTS?

Answer 32

* Before 26/40 – Rx fetoscopic laser ablation * \>26/40- amnioreduction /septostomy * Deliver 34-36/40

Question 33

When and how should the following multiple pregnancies be birthed ? * DCDA * MCDA * MCMA * triplets or more * Conjoined twins

Answer 33

* 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

Question 34

Describe the management of labour of a multiple pregnancy

Answer 34

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