Labour (stages; CTGs)

Question 1

What is the definition of labour? [1]

Answer 1

Onset of regular, painful contractions AND
Cervical changes (dilatation, effacement, softening)

Question 2

The length of the first stage of labour varies widely:

First labour: an average of around [] hours may be expected, rarely would it last longer than 18 hours.

Subsequent labour: may last around [] hours on average and rarely longer than 12 hours.

Answer 2

The length of the first stage of labour varies widely:

First labour: an average of around 8 hours may be expected, rarely would it last longer than 18 hours.

Subsequent labour: may last around 5 hours on average and rarely longer than 12 hours.

Question 3

The length of the second stage varies widely:

Nulliparous (no previous births): normally will last less than [] hours
Multiparous (more than one previous birth): normally will last less than [] hours

Answer 3

Length

The length of the second stage varies widely:

Nulliparous (no previous births): normally will last less than 3 hours
Multiparous (more than one previous birth): normally will last less than 2 hours

Question 4

What are the three stages of labour? [3]

Answer 4

• The first stage is from the onset of labour (true contractions) until 10cm cervical dilatation.
• The second stage is from 10cm cervical dilatation to delivery of the baby.
• The third stage is from delivery of the baby to delivery of the placenta.

Question 5

What are prostaglandins key in preganancy? [1]

What is the clinical significance of them? [1]

Answer 5

Prostaglandins act like local hormones, triggering specific effects in local tissues:
- They play a crucial role in menstruation and labour by stimulating contraction of the uterine muscles.
- They also have a role in the ripening of the cervix before delivery.

One key prostaglandin to be aware of is prostaglandin E2. Pessaries containing prostaglandin E2 (dinoprostone) can be used to induce labour.

Question 6

What are Braxton-Hicks contractions? [1]

Answer 6

Braxton-Hicks contractions are occasional irregular contractions of the uterus.

These are NOT true contractions, and they do not indicate the onset of labour.

They do not progress or become regular. Staying hydrated and relaxing can help reduce Braxton-Hicks contractions

Question 7

What are the signs of labour? [4]

Answer 7

Abdominal pains – regular, initial frequency 2-3 in 10 minutes

Passage of show – mucous plug, brownish or blood stained (not always)

Water leak (often) – but typically waters should break in labour

Others (nausea, vomiting, general malaise…)

Question 8

Describe what is meant by cervical efficacement [2]

Answer 8

Cervix gets thinner and dilates and opens up

Question 9

Describe in detail the first stage of labour
Include the different phases of the first stage of labour [3]

Answer 9

First stage: from the onset of labour until the cervix is fully dilated to 10cm

It involves cervical dilation (opening up) and effacement (getting thinner from front to back)

The “show” refers to the mucus plug in the cervix, that prevents bacteria from entering the uterus during pregnancy, falling out and creating space for the baby to pass through.

Phases of the first stage:
Latent phase:
- From 0 to 3cm dilation of the cervix.
- This progresses at around 0.5cm per hour. There are irregular contractions.

Active phase::
- From 3cm to 7cm dilation of the cervix.
- This progresses at around 1cm per hour, and there are regular contractions.

Transition phase:
- From 7cm to 10cm dilation of the cervix.
- This progresses at around 1cm per hour, and there are strong and regular contractions.

Question 10

NICE guidelines on intrapartum care (2017) refer to the latent first stage and established first stage.

What is the difference between them? [1]

Answer 10

The latent first stage is when there are both:
* Painful contractions
* Changes to the cervix, with effacement and dilation up to 4cm

The established first stage of labour is when there are both:
* Regular, painful contractions
* Dilatation of the cervix from 4cm onwards

Question 11

Describe the second stage of labour [+]

Answer 11

The second stage of labour lasts from 10cm dilatation of the cervix to delivery of the baby.

The success of the second stage depends on “the three Ps”: power, passenger and passage.

1. Power:
- the strength of the uterine contractions.

2. Passenger: the four descriptive qualities of the fetus:
- Size: particularly the size of the head as this is the largest part.
- Attitude: the posture of the fetus. For example, how the back is rounded and how the head and limbs are flexed.
- Lie: the position of the fetus in relation to the mother’s body: Longitudinal lie – the fetus is straight up and down; Transverse lie – the fetus is straight side to side; Oblique lie– the fetus is at an angle.
- Presentation: the part of the fetus closest to the cervix: Cephalic (head first); Shoulder presentation (shoulder first); Breech presentation (legs first)

3. Passage: the size and shape of the passageway, mainly the pelvis.

Question 12

What is descent with regards to labour? [1]

Answer 12

Obstetricians describe the position of the baby’s head in relation to the mother’s ischial spines during the descent phase. Descent is measured in centimetres, from:
* -5: when the baby is high up at around the pelvic inlet
* 0: when the head is at the ischial spines (this is when the head is “engaged”)
* +5: when the fetal head has descended further out

E.g could be +2

Question 13

For how long would you wait before considering ventouse or forceps? [1]

Answer 13

Wait 1hr

Question 14

Describe what happens in the third stage of labour

Answer 14

The third stage of labour is from the completed birth of the baby to the delivery of the placenta.
- Physiological management is where the placenta is delivered by maternal effort without medications or cord traction.
- Active management of the third stage is where the midwife or doctor assist in delivery of the placenta

Question 15

What would indicate active management of the placenta? [2]

What drug is used for active management? [1]

What feeling is associated with active management? [1]

Answer 15

Haemorrhage, or more than a 60-minute delay in delivery of the placenta, should prompt active management.

Active management involves giving a dose of intramuscular oxytocin to help the uterus contract and expel the placenta.

Active management can be associated with nausea and vomiting.

Question 16

Describe the monitoring given in labour for the fetus [1] and mother [5]

Answer 16

Fetus:
* FHR monitored every 15min (or continuously via CTG)

Maternal:
* Maternal pulse rate assessed every 60min
* Maternal BP and temp should be checked every 4 hours
* VE should be offered every 4 hours to check progression of labour
* Maternal urine should be checked for ketones and protein every 4 hours
* Contractions assessed every 30min

Question 17

What is the name for this device? [1]

Answer 17

Pinard stethoscope - for fetal HR

Question 18

Average labour duration:
[] hours for a primipara
[] hours for a multipara

Answer 18

Average labour duration:
8 hours for a primipara
5 hours for a multipara

Question 19

A partogram is used to monitor the active phase of the first stage of labour.

Describe what you would measure on the partogram and what it would indicate if these were atypical [+]

Answer 19

A tool for monitoring maternal and foetal wellbeing during the active phase of labour, and a decision-making aid when abnormalities are detected

Fetal HR
- Normal is 110-160

Maternal pulse, BP, temperature
- raised if chorioamnionitis, UTI, group B streptococcal infection)

Maternal urianalysis
- protein = pre-eclampsia/liquor contamination; glucose = diabetes; ketones = starvation; blood = UTI/obstructed labour

Contractions:
- Frequency per 10 mins: 2nd stage of labour aim is 1min contractions in 10 mins, 3-5 strong)
- Strength
- Regularity

Cervical dilatation:
- PV exam performed every 4hrs: aim is 1cm/hr primiparous, 2cm/hr multiparous
- Alert line: 1cm/2hrs if primiparous or 1cm/hr if multiparous

Head descent:
- PV exam every 4 hrs
- Assess: Fifths palpable per abdomen; station of presenting part (measured in relation to ischial spine); position (orientation of fetal head - feel for fontanelles/sutures); moulding (extent of overlapping fetal skull bones); caput: swelling of presenting part

Liquor:
- Noted every hour
- Assess if intact: clear (membrane rupture), bloody (placental abruption) or meconium present (fetal distress)

Question 20

Which medical devices would you use for HR in 1st or 2nd stage if there were no concerns? [2]

During 1st and 2nd stage how often would you check? [2]

What would you move to next if you were concerned? [1]

Answer 20

Intermittant ascultations: Pinard stethoscope or Doppler ultrasound

1st stage:
- Every 15 minutes, after a contraction, for 1 minute; record maternal pulse hourly

2nd stage: Every 5 minutes, after a contraction, for 1 minute; record maternal pulse every 15 min

Record accelerations and decelerations !!!

Move to CTG if any concerns

Question 21

CTG:
- What is baseline tachycardia [1] and bradycardia [1]

• What are potential causes of fetal tachycardia? [4]
• What are potential causes of fetal bradycardia? [2]

Answer 21

Baseline bradycardia: HR < 100
- Increased fetal vagal tone
- Maternal beta blocker use

Baseline tachycardia: HR > 160:
- Maternal pyrexia
- chorioamnionitis
- fetal hypoxia
- fetal or maternal anaemia
- prematurity
- hyperthyroidism

Question 22

CTG:
- What is fetal bradycardia? [1]
- What are two common causes for fetal bradycardia? [2]
- Severe prolonged bradycardia count as less than [] bpm for more than 3mins. What are the causes? [4]

Answer 22

Fetal bradycardia is defined as a baseline heart rate of less than 110 bpm.

Fetal bradycardia is common in postdate gestation or OP or transverse presentations

Severe prolonged bradycardia (less than 80 bpm for more than 3 minutes) indicates severe hypoxia:
* Prolonged cord compression
* Cord prolapse
* Epidural and spinal anaesthesia
* Maternal seizures
* Rapid fetal descent

Question 23

Describe what is meant by an early deceleration in CTG? [1]
What are the causes of early deceleration in CTG? [1]

Answer 23

Deceleration of the heart rate which commences with the onset of a contraction and returns to normal on completion of the contraction
- They are caused by the uterus compressing the head the fetus, stimulating the vagus nerve of the fetus, slowing the heart rate

Question 24

Why does variability occur in CTGs? [3]

What is normal / reassuring variability? [1]

Answer 24

Variability occurs as a result of the interaction between the nervous system, chemoreceptors, baroreceptors and cardiac responsiveness.
- Normal variability is between 5-25 bpm

Question 25

What reassuring [1], non-reassuring [2] and abnormal [3] fetal HR variability?

Answer 25

**Reassuring:** - **5 – 25 bpm** **Non-reassuring:** * **less than 5** **bpm** for between **30-50 minutes** * **more than 25 bpm** for **15-25 minutes** **Abnormal**: * **less than 5 bpm** for **more than 50 minutes** * **more than 25 bpm** for **more than 25 minutes** * **sinusoidal**

Question 26

What can caused reduced variability in CTGs? [6]

Answer 26

**Fetal sleeping**: this should **last no longer than 40 minutes** (this is the most common cause) **Fetal acidosis** (due to hypoxia): more likely if **late decelerations** are also present **Fetal tachycardia** **Drugs**: opiates, benzodiazepines, methyldopa and magnesium sulphate **Prematurity**: variability is reduced at earlier gestation (< 28 weeks) **Congenital heart abnormalities**

Question 27

Define what decelerations are on CTGs [1]

Answer 27

**Decelerations** are an **abrupt decrease** in the **baseline fetal heart rate** of **greater than 15 bpm for greater than 15 seconds.** - The fetal heart rate is controlled by the autonomic and somatic nervous system. In response to hypoxic stress, the fetus reduces its heart rate to preserve myocardial oxygenation and perfusion. Unlike an adult, a fetus cannot increase its respiration depth and rate. This reduction in heart rate to reduce myocardial demand is referred to as a deceleration.

Question 28

Describe the difference in causes between early, late and prolonged decelerations [3]

Answer 28

**Early** **decelerations** start when the **uterine contraction** **begins** and **recover** when **uterine contraction stops** - This is due to **increased fetal intracranial pressure** causing **increased vagal tone.** - It therefore **quickly** **resolves** **once** the **uterine contraction ends** and **intracranial pressure reduces** - considered to be **physiological** and **not** **pathological**. **Late decelerations** - **begin** at the **peak** of the **uterine contraction** and **recover** after the **contraction ends** - This type of **deceleration** indicates there is **insufficient blood flow to the uterus and placenta**. As a result, **blood flow to the fetus** is **significantly** **reduced** causing **fetal hypoxia and acidosis.** **Prolonged deceleration:** * A prolonged deceleration is defined as a deceleration that **lasts more than 2 minutes:** * If it lasts **between 2-3 minutes** it is classed as **non-reassuring.** If it lasts **longer than 3 minutes** it is immediately classed as **abnormal**.

Question 29

Name 3 causes of late deceleration CTGs [3]

Answer 29

Causes of **reduced uteroplacental blood** flow include: * Maternal hypotension * Pre-eclampsia * Uterine hyperstimulation * asphyxia * placental insufficiency

Question 30

Describe what causes variable decelerations

Answer 30

**Variable decelerations** are usually caused by **umbilical cord compression**. The mechanism is as follows: **1.** The umbilical vein is often occluded first causing an acceleration of the fetal heart rate in response. **2**. Then the umbilical artery is occluded causing a subsequent rapid deceleration. **3**. When pressure on the cord is reduced another acceleration occurs and then the baseline rate returns.

Question 31

The accelerations before and after a variable deceleration are known as the **[]** of deceleration. What do they indicate? [1]

Answer 31

The accelerations before and after a variable deceleration are known as the **shoulders of deceleration** - Their presence **indicates the fetus is not yet hypoxic** and is **adapting to the reduced blood flow.** - Variable decelerations without the shoulders are more worrying, as it suggests the fetus is becoming hypoxic.

Question 32

What does a sinusoidal CTG patten indicate? [3]

Answer 32

A **sinusoidal** **pattern** usually indicates one or more of the following: * Severe fetal hypoxia * Severe fetal anaemia * Fetal/maternal haemorrhage

Question 33

Describe how you would present a CTG

Answer 33

**DR** – **Define Risk** (define the risk based on the individual woman and pregnancy before assessing the CTG) **C** – Contractions **BRa** – Baseline Rate **V** – Variability **A** – Accelerations **D** – Decelerations **O** – Overall impression (given an overall impression of the CTG and clinical picture)

Question 34

Describe how you go through each of the following: **DR C BRaVADO**

Answer 34

**DR**: - **Maternal medical illness**: Gestational DM; HTN: Asthma - **Obstetric** **complications**: pre-eclampsia; oxytocin induced; post-date gestation; previous c section; IUGR - **Others**: smoking, drug abuse **Contractions**: - Record no per 10 minute period - Each **big square is 1 minute** - **How** **long**? - **How strong**? **BRa: Baseline rate**: - A normal fetal heart rate is between **110-160 bpm** - Fetal **tachycardia**? - Fetal **bradycardia**? **V: Variability**: - Baseline variability refers to the variation of fetal heart rate from one beat to the next. - **Reassuring**: 5 – 25 bpm - **Non-reassuring**: < 5 bpm for 30-50 mins; > 25bpm for 15-25 mins - **Abnormal**: < 5 bpm for 50+ mins; > 25bpm for 25+ mins **A: Accelerations**: - **abrupt increase** in the baseline fetal heart rate of greater than **15 bpm for greater than 15 seconds** - The presence of accelerations is **reassuring**. **D: Decelerations** - abrupt decrease in the baseline fetal heart rate of greater than 15 bpm for greater than 15 seconds - **Early**: physiological - **Variable**: There is a fall of more than 15 bpm from the baseline. Variable decelerations often indicate intermittent compression of the umbilical cord, causing fetal hypoxia. Brief accelerations before and after the deceleration are known as shoulders, and are a reassuring sign that the fetus is coping - **Late**: gradual falls in heart rate that starts after the uterine contraction has already begun. They may be caused by excessive uterine contractions, maternal hypotension or maternal hypoxia - **Prolonged**: last between **2 and 10 minutes** with a **drop of more than 15 bpm** from **baseline**. This often indicates compression of the umbilical cord, causing fetal hypoxia. These are abnormal and concerning. **O: Overall impression**: - The overall impression can be described as either **reassuring, suspicious or abnormal**

Question 35

What's a mneumonic for remembering what the causes of decelerations / acelerations are? [4]

Answer 35

**VEAL CHOP** **V**ariable decelerations --> **C**ord compression **E**arly decelerations --> **H**ead compression **A**ccelerations --> **O**kay! **L**ate decelerations --> **P**lacental Insufficiency

Question 36

What is the 'rule of 3's' for fetal bradycardia when they are prolonged? [4]

Answer 36

**3** minutes – call for help **6** minutes – move to theatre **9** minutes – prepare for delivery **12** minutes – deliver the baby (by 15 minutes)

Question 37

Based off a CTG, you perform a fetal scalp stimulation. What would be a reassuring sign? [1]

Answer 37

**Fetal scalp stimulation** (an **acceleration** in response to **stimulation** is a reassuring sign)

Question 38

What are the 4 Ps that are the main components of labour process? [4] *Facotors that influence each other during childbirth*

Answer 38

**P**ysche **P**ower **P**assage **P**assenger

Question 39

What is the normal cephalic presentation for a fetus? [1]

Answer 39

In normal (flexed) presentation the presenting diameter is **suboccipito-bregmatic, measuring on average 9.5 cm.**

Question 40

FYI

Question 41

Describe the different positions of the baby's head during labour (and which ones are problematic) [4]

Answer 41

**Occipito-anterior (OA):** - optimal position - baby is head down with his or her face looking at spine **occipito-posterior (OP)**: - baby is head down, facing naval **Occiput Transverse (OT)** - **R** or **L** - This is when the baby is lying at a right angle across the parent’s abdomen. **Breech** - Breech is when the baby is lying bottom down in the womb.

Question 42

How can you determine which position the baby is during birth by feeling its head? [1]

Answer 42

Look at the **fontanelles** to **determine** **position** - **Posterior** is **triangular**; **hard**; - **Anterior** is a **diamond**; **soft** - Therefore if the posterior further up: OA Can feel the sagitalle suture (long one) - follow along until other suture. If theres 3 its posterior; if 4 and anterior is soft

Question 43

What are the different mechanisms involved in labour? [7]

Answer 43

Engagement Descent Flexion Internal rotation Descent Delivery by extension External rotation (restitution)