Normal Labour and Delivery

Question 1

What is labour?

Answer 1

Process by which regular, painful contractions bring about effacement and dilatation of the cervix and descent of the presenting part ultimately leading to expulsion of the fetus and the placenta of the mother.

Question 2

How is labour initiated?

Answer 2

In the fetus: There is a rise in ACTH from anterior pituitary gland, rise in Angdrogens and glucocorticoids from the adrenal glands.

In the placenta: Progesterone levels drop and estrogen levels rise which are important for rise in prostaglandins.

In the mother: There is an increase in uterine sensitivity to stretching. Increase in uterine contractions. Increase in uterine sensitivity to oxytocin. Softening of the cervix.

Question 3

What initiates the uterine contractions?

Answer 3

Rise in oestrogen leads to rise in prostaglandins which lead to increased uterine contractions, increased uterine sensitivity to oxytocin, and to softening of the cervix.

Labour initiates stretching of the cervix and the vagina which leads the posterior pituitary to increase contractions by producing oxytocin which creates a positive feedback loop leading.

Question 4

What are pre labour irregular contractions called?

Answer 4

Braxton Hicks contractions

Question 5

What happens during the prelabour period?

Answer 5

Myometrial excitement leading to braxton hicks contractions.

Descent of foetal head into the pelvis

Cervical ripening (Cervix becomes soft - collagen contractions are reduced and replaced by water content)

Show (Loss of blood-tinged mucoid plug within the cervix or the amniotic sac can rupture i.e water breaking)

Question 6

What is cervical effacement?

Answer 6

Refers to gradual inclusion of cervix into the lower uterine segment

Question 7

What is cervical dilatation?

Answer 7

The opening of the cervix from closed to full dilatation

Question 8

What are the stages of labour?

Answer 8

3 stages:

1st stage: Between the time of onset of labour until the time of full cervix dilatation (10cm).

2nd stage: Full dilatation of the cervix until expulsion of the foetus from the birth canal. (Lasts 1 - 2 hours in nullipara and <1 hour in multipara usually)

3rd stage: Begins after delivery of baby and ends in expulsion of the placenta and membranes. (doesn’t usually last longer than 30 minutes)

Question 9

What are the 2 parts of the first stage of labour?

Answer 9

Latent labour: Time between onset of labour to 4cm dilatation. This stage has no time frame and can take really long or can happen really quickly (average duration is 12 - 14 hours in a nullipara or 8 hours in a multipara)

Active labour: Describes the time from 4cm to 10cm dilatation. 1cm per hour

Question 10

What is a nullipara vs multipara?

Answer 10

Nullipara: never given birth before

Multipara: given birth several times before.

Question 11

What influences labour?

Answer 11

Passages (pelvis and pelvic floor)

Powers (Contractions and secondary powers of expulsion)

Passenger (Foetal presentation, attitude and foetal size/position)

Question 12

Which direction is the pelvic inlet, the mid-cavity, and the pelvic outlet largest? What does this mean?

Answer 12

Inlet - ~13cm transverse

Mid-cavity - round 12 cm

Pelvic outlet - AP direction ~13cm

Head starts transversely rotates mid cavity and then goes to AP direction.

Question 13

What guides foetal head movement in baby?

Answer 13

The pelvic floor muscles rotate and flex the presenting part of the foetus.

Question 14

How are the uterine contractions coordinated?

Answer 14

The contractions start at the uterine fundus and sweep towards the lower segment drawing the lower segment up over the presenting part so the cervix effaces and dilates and the foetus descends into the pelvis.

Question 15

What is fundal dominance?

Answer 15

The contraction starts and lasts longer in the fundus where it is also most intense.

Question 16

What are the secondary powers of expulsion?

Answer 16

Pressure from presenting part on the pelvic floor stimulates nerve receptors and the woman experiences the urge to push.

The mother’s response is to contract abdominal muscles and the diaphragm.

Question 17

What are the foetal factors that influence passage?

Answer 17

Lie (Relationship between the long axis of foetus and long axis of maternal spine)

Presentation (Cephalic or breech (~4 - 5%)

Attitude (Flexion of head is good, brow presentation is undeliverable)

Position (relationship between presenting part and mother’s pelvis)

Ability to alter head size (fontonelles and sututes that can mould)

Question 18

How is foetal position adjusted during delivery?

Answer 18

Whatever hits pelvic floor rotates anteriorly

Question 19

What is the denominator of foetal position?

Answer 19

The foetal occiput which needs to face anteriorly in the mother.

Question 20

What is moulding an indicator of?

Answer 20

Moulding of the foetal head indicates difficulty of the head fitting through the pelvic cavity.

Question 21

How can progress of labour be monitored?

Answer 21

Abdominal palpations (Confirm lie is longitudinal, foetal position is cephalic, position of foetal back, attitude of good flexion and position occipital lateral or anterior)

Vaginal examinations (Progressive effacement and dilatation of cervix (1cm an hour during active phase of labour), progressive descent of presenting part, Assess flexion and position)

Palpation of contractions (Frequency, length, and strength)

Question 22

What does cervicograph do?

Answer 22

Provides graphic representation of the progress of cervix during labour.

Question 23

What do the alert line and action line refer to?

Answer 23

Cervical opening needs to be monitored; during the latent phase it is OK for the cervix to take long to open to 4cm. However, during the active phase we need to see 1cm per hour.

Alert line means careful assessment is needed.

Action line means action needs to be taken (I.e oxytocin infusion to stimulate contractions)

Question 24

What should be monitored during labour?

Answer 24

Cervicograph (monitor cervix size and contractions)

Maternal well-being (Vital signs, input and output, pain management, Continuous supportive environment) [ensure bladder is not distended]

Question 25

How can pain be managed in labour?

Answer 25

Many choices (epidural, opioids, inhalational)

Natural methods (water / massages / heat / position / aromatherapy)

Support (positioning / caregiving / psychological support)

Question 26

How is foetal wellbeing monitored?

Answer 26

Foetal heart rate is measured (110 - 160 bpm)

Question 27

What are the cardinal movements of labour?

Answer 27

Engagement (descent has progressed so that maximum diameter of foetal head has passed through the pelvic brim)

Descent continues and occiput reaches the pelvic floor. Occiput begins to rotate on the pelvic floor

Once rotation is complete face starts to sweep the pelvic floor and the head begins to stretch the perineum

Head further extends the perineum and delivers

The foetal head realigns to the A-P plane of the shoulders, the internal shoulders rotate on the pelvic floor.

Anterior shoulder is under the symphysis pubis and delivers by lateral flexion followed by delivery of posterior shoulder

Question 28

What must be monitored during the third stage of labour?

Answer 28

It begins after delivery of baby and involves separation and expulsion of the placenta and membranes and control of haemorrhage from the placental site.

Question 29

What must be done immediately after delivery?

Answer 29

Detection of any postpartum complications

Promotion of early mother-baby interaction

Initiation of breastfeeding