Abnormal labour

Question 1

What is induction of labour?

Answer 1

Artificially trying to start labour. Involves using medications/devices to bring about cervical changes required to begin labour. May involve artificial amniotomy (rupture of membranes).

Approx 1 in 5 pregnancies are induced

Question 2

What is cervical ripening?

Answer 2

• Process by which the cervix gets ready for labour.
• Naturally it does this by softening, thinning down, dilating and moving anteriorly.
• In an induced labour - need to mimic this process.

Question 3

What 2 things are used to mimic cervical ripening during an induced labour?

Answer 3

• Prostaglandin medication - usually inserted into vagina - pessary / gel e.g misoprostol
• Balloon - inserted through cervix and blows up to try stretch open the cervix

Question 4

What is the Bishop’s score?

Answer 4

A pre-labour scoring system that assesses the cervix and whether it is ready for labour.

• A lower score (<5) means the cervix is not ready for labour and unlikely to start without ripening/softening - use things like balloon catheter or medications e.g prostaglandins which ripen the cervix i.e get it ready for delivery
• Score of 7 or more is an indication that induction will be more successful - you would do an amniotomy at this point (artificial rupture of the membranes) and then start IV syntoconin (artificial oxytocin) infusion to initiate/achieve adequate uterine contractions for delivery

Question 5

Once labour has been induced, which drug is administered to achieve adequate uterine contractions? (4-5 contractions in 10 minutes)

Answer 5

IV synthetic oxytocin e.g syntocinon

• If contractions spontaneously start after induction then this is not necessary

Question 6

What are some common reasons/indications for induction of labour?

Answer 6

• Diabetes
• Post due date (term + 7 days) - the risk is that after 41-2 weeks the risk of still birth increases
• Maternal need for planning of delivery i.e if a women is on anticoagulant for DVT or PE
• Foetal reasons - continuing the pregnancy may be detrimental to the foetus i.e growth concerns
• Social / maternal request

Question 7

What are some causes of complications during labout that may mean labour may not be able to progress?

Think ‘Powers, passages, passenger’

Answer 7

• Powers
  
  • Inadequate uterine activity (powers)
• Passeges
  
  • Cephalopelvic disproportion (CPD)
  • Other reasons for obstruction e.g. fibroid
• Passenger
  
  • Malposition
  • Malpresentation

Question 8

Throughout labour abdominal and vaginal examinations are used to determine how the pregnancy is progressing.

What things are looked for during these examinations? (4)

Answer 8

• Cervical effacement (thinning)
• Cervical dilatation (cm)
• The descent of the foetal head through the maternal pelvis
• Palpate abdomen to determine foetal lie and to feel contractions

Question 9

What happens if there is an inadequate number of contractions?

Answer 9

The foetal head will not descend and exert force on the cervix and the cervix will not dilate.

Question 10

What is the risk associated with an obstructed labour? (Inadequate uterine activity)

Answer 10

Continuing to labour and contract when the cervix isn’t dilating could result in uterine rupture (rare in the UK)

Need to keep an eye on labour and ensure it is progressing normally

Question 11

What is Cephalopelvic disproportion (CPD)?

And what 2 clinical signs might you see with this?

Answer 11

A mismatch between the mother’s pelvis dimensions and the baby.

• It is relatively rare
• The fetal head is in the correct position for labour but is too large to negotiate the maternal pelvis and be born
• May see some clinical signs - these can be normal, however, if they were considerable and early on in pregnancy then this would be concerning.
  
  • Caput - swelling on the top of the baby’s head
  • Moulding - sutures on baby’s head cross over each other

Question 12

Apart from CPD, what are some other passage obstructions?

Answer 12

• Placenta praevia - low lying placenta - essentially the placenta is presenting - it comes out first and cuts off blood supply to baby
• Foetal anomaly i.e hydrocephalus
• Fibroids esp in the cervix

Question 13

What is Malposition?

Answer 13

When the baby’s head is in an suboptimal position for labour and ‘relative’ CPD occurs. They are in normal cephalic presentation though.

Question 14

What are the main causes of foetal distress?

Answer 14

• Common
  
  • No cause is found
  • Hypoxia
  • Infection
• Rare
  
  • Cord prolapse
  • Placental abruption
  • Vasa praevia

Question 15

How does having too many uterine contractions result in foetal distress?

Answer 15

Uterine Hyper-stimulation can cause insufficient placental blood flow which in turn can result in foetal distress

Question 16

How is the foetal well being monitored during labour?

Answer 16

• Intermittent auscultation of the foetal heart - low risk pregnancies (no RF, no concerns of infection etc)
• Cardiotocography (CTG) - continuous
• Foetal blood sampling
• Foetal ECG

Question 17

What is Meconium?

Answer 17

Sometimes, the foetus passes a stool in the womb. This bowel movement is called meconium, which goes into the amniotic fluid.

If a baby ingests meconium on delivery, it can have health consequences.

Question 18

How is blood taken from the foetus?

Answer 18

• Speculum used to take foetal scalp blood sample.
• This is done when there is abnormal CTG (continuous monitoring of foetal heart rate) and concern about foetal distress.
• Can tell if baby is hypoxic

Provides a direct measurement from baby:

• We can measure pH and base excess
• Also can measure lactic acid
• pH gives a measure of likely hypoxaemia

If FBS is abnormal then that would usually instigate an immediate delivery i.e foreceps or c-section.

Question 19

What are common complications in the 3rd stage of labour?

Answer 19

Occur after the birth - even if it is a straight forward labour and delivery. 3rd stage = from birth to delivery of placenta.

• Retained placenta - placenta doesn’t deliver
• Post partum haemorrhage
• Tears
  
  • Graze
  • 1st degree
  • 2nd degree
  • 3rd degree - involves anal sphincter complex
  • 4th degree - involves rectal mucosa

Question 20

Operative delivery options

Answer 20

• Instrumental deliveries (forceps / ventouse - suction)
• Planned (elective) Caesarean section (CS)
• Emergency CS

Operative vaginal birth or caesarean section may be necessary when problems occur in labour to prevent fetal and maternal morbidity and mortality

Question 21

Anaemia in pregnancy

Answer 21

• Iron deficiency anaemia
  
  • Most common cause of anaemia and most common type in pregnant women
  • Because the expansion in plasma volume is greater than the increase in red cell mass there is a fall in haemoglobin concentration, haematocrit and red cell count
• Pernicious anaemia - B12 deficiency
  
  • Most common cause of vitamin B12 deficiency
  • Pernicious anaemia causes your immune system to attack the cells in your stomach that produce the intrinsic factor, which means your body is unable to absorb vitamin B12
  • If you’re pregnant, not having enough vitamin B12 can increase the risk of your baby developing a serious birth defect known as a neural tube defect.
• Sickle cell disease
  
  • Abnormality in haemoglobin which leads to a rigid, sickle-like shape RBC under certain circumstances.
  • May not cause any complications during pregnancy