High Risk Pregnancy

Question 1

What are the risk factors for multiple pregnancy?

Answer 1

Assisted conception (IVF, ovulation induction),
Increased maternal age,
Ethnic origin (West africa),
Family History

Question 2

What do the following terms mean:
Zygosity,
Chorionicity,
Amnionicity

Answer 2

Zygosity - number of fertilized eggs.
Chorionicity - number of placentas
Amnionicity - number of sacs

Question 3

What are Dizygotic twins?

Answer 3

Most common type.
Two eggs and two sperm so no more identical than siblings.
They are always DCDA (dichorionic and diamniotic), meaning always have two placenta and two sacs

Question 4

What are monozygotic twins?

Answer 4

When one egg is fertilized so they are identical.
If splits before day 4 (before chorion development) then they are dichorionic and diamniotic.

Splits from day 4-8 (prior to amnion development) then they are monochorionic and diamniotic.

Split after day 9 (after amnion development) then monochorionic and monoamniotic. Increased risk of conjoined twins.

Dichorionic - Two placentas
Diamniotic - Two amniotic sacs

Question 5

What ultrasound signs indicate Monochorionic vs dichorionic

Answer 5

Mono - Lambda sign.
Di - T sign

Question 6

What are the maternal antenatal complications of multiple pregnancy?

Answer 6

Hyperemesis gravidarum,
Pre-eclampsia,
Gestational diabetes,
Placenta praevia,
Minor complications

Question 7

What are the fetal complications of multiple pregnancy?

Answer 7

Miscarriage,
Congenital anomaly,
Growth restriction,
Pre-term delivery
If monochorionic then increased risk of twin to twin transfusion syndrome (recipient is larger with polyhydramnios), acute transfusion and twin reversed perfusion sequence.

Question 8

How do you diagnose multiple pregnancies?

Answer 8

Ultrasound - Essential to determine chorionicity. Screen with nuchal translucency for aneuploidy.

Invasive proceedures - Amniocentesis and chorionic villus sampling.

Question 9

How can you monitor foetal growth in multiple pregnancies?

Answer 9

Regular ultrasounds!
Dichorionic twins 4 weekly from 24 weeks.
Monochorionic twins 2 weekly from 16 weeks.

Question 10

When are twins delivered?

Answer 10

37 weeks for DCDA twins
36 weeks for MCDA twins

Question 11

Explain features of delivery for twins

Answer 11

Analgesia for mum - often epidural.
Monitoring during labor: Maternal - BP IV access, fluids and ranititdine,
Faetal: Continuous CTG, abdominal and fetal scalp electrodes

Question 12

What are the postnatal complications of twins/multiple pregnancies?

Answer 12

Increased risk of PPH,
Increased risk of post natal depression, anxiety, relationship issues and bereavement

Question 13

What specific complications affect monochorionic twins?

Answer 13

Acute transfusion,
Twin to twin transfusion syndrome,
Twin reversed arterial perfusion sequence

Question 14

Describe features of an acute transfusion

Answer 14

Death of one twin in utero leads to increased risk of hypoxic-ischaemic injury in survivor due to acute transfusion from health to dying twin. Risk of exsanguination of healthy twin into dying twin.
Delivery expedited if compromise detected.

Question 15

Describe features of twin to twin transfusion syndrome

Answer 15

Connection between bloody supplies of the two fetus. Recipient fetus receives more blood and gets heart failure and polyhydramnios. Donor receives less blood and gets growth restriction, anaemia and oligohydramnios.

Question 16

Explain the diagnosis, staging and management of twin to twin transfusion syndrome?

Answer 16

Diagnosis is via ultrasound.
Quintero staging
Management - Fetoscopic laser ablation of anastomosis or cord occlusion.

Question 17

What is twin reversed arterial perfusion syndrome?

Answer 17

Where two cords linked by big aterio-arterial anastamosis and retrograde perfusion. it is a severe form of TTTS.
There is a pump twin and a perfused twin.
Managed with ablation of anastamosis.

Question 18

Describe features of monoamniotic twins

Answer 18

Almost all develop cord entanglement and there is high mortality. Elective C-section required at 32-33 weeks

Question 19

what is a breech presentation and what are the different types?

Answer 19

When baby comes feet first. It can either be flexed, footling or extended.

Question 20

What are the associations with breech presentations?

Answer 20

Multiple pregnancies,
Bicornate uterus,
Fibroids,
Placental praevia,
Polyhydramnios,
Oligohydramnios
Fetal anomaly

Question 21

What is the management of breech presentation?

Answer 21

External cephalic version - 50% success rate. Must do CTG during and after procedure. May need anti-D.
Done at 36 weeks if nulliparous and 37 for multiparous women. Before this, they are likely to turn on their own.

Question 22

What are the contraindications to external cephalic version?

Answer 22

Absolute - Antepartum haemorrhage within last 7 days, abnormal CTG, major uterine anomaly, ruptured membranes, multiple pregnancies and absence of maternal consent.

Relative - Nuchal cord, FGR, proteinuric pre-eclampsia, oligohydramnios, major fetal anomalies, hyperextended fetal head, maternal morbid obesity.

Question 23

What are the risks of vaginal vs C-sections in breech presentations?

Answer 23

Vaginal is mainly risks to fetus - Intracranial injust, widespread bruising, damage to internal organs, spinal cord transection, umbilical cord prolapse and hypoxia.
C-section is mainly maternal risks - surgical morbidity and mortality

Question 24

What are the definitions of the following:
Pre-term
Very pre-term,
Extremely pre-term,
Pre-term labour,
Pre-term Pre-labour rupture of the membranes

Answer 24

Pre-term - Less than 37 weeks
Very pre-term - 28 to 32 weeks
Extremely pre-term - <28 weeks

Pre-term labour - Regular uterine contractions acompanied by effacement and dilation of cervix between 20-37 weeks.

Pre-term Pre-labour rupture of the membranes - Rupture of fetal membranes before 37 weeks and before onset of labout.

Question 25

What are the definitions of the following:
Low birth weight
Very low birth weight
Extremely low birth weight

Answer 25

Low birth weight < 2501g
Very low birth weight < 1501g
Extremely low birth weight < 1000g

Question 26

What are the complications of preterm labour?

Answer 26

Perinatal morbidity and mortality.
Immature fetal organs
Long term disability eg lung disease, cerebral palsy.

Question 27

Explain the role of maternal corticosteroids

Answer 27

IM Betamethasone/dexamethasone is given in divided doses over 24 hours. Used in preterm labour/rupture of membranes.
Crosses placenta and increases amount of fetal pulmonary surfactant which reduces respiratory distress syndrome, intraventricular cerebral haemorrhage, neonatal death, necrotizing enterocolitis.

Question 28

What is the classification of antepartum haemorrhage?

Answer 28

Minor < 50ml
Moderate - 50-1000ml but no hypovolaemic shock.
Major > 1000ml +/- hypovolaemic shock

Question 29

What are the local causes of antepartum haemorrhage

Answer 29

Vulva,
Vagina,
Cervix: cervical ectropion or polyps.
Cervical carcinoma

Question 30

Explain the classification of placenta praevia

Answer 30

I - placenta encroaches lower uterine segment.
2 - Reaches internal os of cervix.
3 - Covers part of internal os.
4 - completely covers internal os.

Question 31

What are the risks of placenta praevia?

Answer 31

A sudden unpredictable major/massive haemorrhage.
Abnormally invasive placenta or placenta accreta

Question 32

What is the management of placenta praevia

Answer 32

May be admitted from 30-32 weks till delivery. Elective delivery at 36-37 weks. Emergency delivery may be required

Question 33

What is placenta accreta?

Answer 33

When the placenta implants deeper through the endometrium and invades the myometrium. Diagnosed via ultrasound
This markedly increases risk of PPH and women may require a hysterectomy following an elective C-section around 35 weeks.
RFs are previous C-section or previous placenta accreta.

Question 34

What is placental abruption and its risk factors?

Answer 34

Bleeding between the placenta and uterus, often with a degree of placental separation. May cause fetal hypoxia and acidosis.
RFs: Previous abruption, HTN, thrombophilia, PROM, multiple pregnancy, folic acid def, cocaine smoking, social deprivation.

Question 35

What is the management of placental abruption?

Answer 35

Fetus alive and < 36 weeks: No distress then observe closely and steroids. If distressed then immediate caeserean.

If > 36w and alive: C-section if distressed, vaginal delivery if no ditress.

Fetal death - induce vaginal delivery.

Question 36

How can you determine the difference between placenta praevia and placental abruption?

Answer 36

Abruption - Shock is out keeping with visible loss and there is constant pain. There is a tense, woody uterus.

Praevia: Shock in keeping with visible loss, no pain and soft uterus.