Labour

Question 1

Define labour.

Answer 1

Regular + painful uterine contractions that cause progressive dilation + effacement of the cervix.
Normal term labour is usually between 37-42w
EDD is 40w

Question 2

What are Braxton Hicks contractions?

Answer 2

Throughout 3rd trimester, involuntary contractions of the uterine smooth muscle occur
Irregular
“practice contraction”

Question 3

What are the borders of the pelvic inlet?

Answer 3

Posteriorly: Sacral promontory
Laterally: Iliopectineal line
Anteriorly: Pubic symphysis

Question 4

What are the borders of the pelvic outlet?

Answer 4

Posterior: Tip of the coccyx
Lateral: Ischial tuberosity
Anterior: Pubic arch

Question 5

What is foetal lie?

Answer 5

the relation of the long axis of the fetus in relation to the mother
Longitudinal
Oblique
Transverse

Question 6

What is foetal presentation?

Answer 6

the part of the body of the foetus which leads
cephalic
frank breech: most common
complete breech
footling

Question 7

Describe each breech type

Answer 7

Frank: legs flexed at hip + extended at knees
Complete: legs flexed at hips + knees (cross-legged)
Footling: one or both legs extended at the hip

Question 8

What is foetal position?

Answer 8

the position of the presenting part in relation to a point on the maternal pelvis
L/R occipitoposterior
L/R occipitoanterior
L/R occipitotransverse

Question 9

What is foetal engagement?

Answer 9

The passage of the largest part of the presenting part through the pelvic brim.
If fetal head is at the level of the ischial spines then it is engaged.

Question 10

What is foetal station?

Answer 10

The relation of the presenting part to the ischial spine.

Question 11

What are the stages of labour?

Answer 11

First stage: dilation to 10cm
Latent phase: 0-3cm dilation
Active phase: painful regular contractions leading to 10cm dilation

Second stage: 10cm to birth of foetus

Third stage: Placenta delivery

Question 12

What happens in the latent stage of labour?

Answer 12

Uncoordinated contractions

Slow dilation up to 4cm

Early admission is not recommended at this stage

Question 13

What is the rate of dilation and frequency of contractions in the first stage of labour?

Answer 13

1cm/ h nulliparous
2cm/ h multiparous
Contractions every 2-3 mins

Question 14

How long does the latent stage of labour tend to last?

Answer 14

18h for 1st labour

12h for 2nd labour

With each subsequent labour, the time decreases

Question 15

Describe the passive movements undertaken by the foetus in labour

Answer 15

Engagement
Descent
Flexion
Internal rotation
Crowning
Extension of the presenting part
Restitution
External rotation
Lateral flexion

Question 16

What causes descent?

Answer 16

Increased abdominal muscle tone
Braxton hicks
Fundal dominance of uterine contractions during labour
Increased frequency + strength of contractions during labour

Question 17

What is engagement?

Answer 17

Largest diameter of fetal head descends into maternal pelvis.
Fetal head is 3/5th palpable or less.
Primips: usually weeks before labour
Head usually occipital-transverse

Question 18

What is flexion?

Answer 18

Fetal neck flexes (chin to chest) ensures the smallest diameter is presented at the pelvic outlet
Occurs due to head pushing against tissues of pelvic floor

Question 19

What is internal rotation?

Answer 19

Foetus internally rotates from left or right OT position 90-degrees, to an occipital-anterior, oblique position, to lie under the subpubic arch.

Occurs during established labour + is commonly completed by start of the 2nd stage.

Question 20

What is crowning?

Answer 20

= Widest diameter of fetal head successfully negotiates through the narrowest part of the maternal bony pelvis

Head no longer retreats between contractions.

Question 21

What is extension of the presenting part?

Answer 21

Occiput slips beneath the suprapubic arch allowing the head to extend.
Fetal head facing maternal back with its occiput anterior.

Question 22

What is restitution?

Answer 22

external movement of fetal head that corrects the torsion of neck sustained during internal rotation.
Direction of movement opposite to that of the internal rotation

Question 23

What is external rotation?

Answer 23

the movement of the head due to the internal rotation of the shoulder as it comes into the antero–posterior diameter of the pelvic outlet.
The anterior shoulder escapes under the pubic arch, while the posterior shoulder sweeps over the perineum.

Question 24

What is lateral flexion?

Answer 24

Upward traction assisting the delivery of the posterior shoulder.

Question 25

What is caput succedaneum?

Answer 25

Diffuse swelling of the scalp, caused by pressure of the scalp against the dilating cervix.
Crosses suture lines (like a cap)
Spontaneously resolves

Question 26

What is the strongest risk factor for cephalohaematoma?

Answer 26

Vacuum assisted delivery
(though also a/w forceps)

Question 27

What is cephalohaematoma?

Answer 27

accumulation of subperiosteal blood
Typically in the parietal or occipital region
Caused by shearing forces on skull during birth
GRADUAL bleed- not immediate at birth
Does NOT cross suture lines
May take months to resolve
Jaundice may develop as complication

Question 28

What is a subgaleal haematoma?

Answer 28

scalp bleeding in the potential space between the periosteum + galeal aponeurosis.
superficial to periosteum thus CAN cross suture lines
Life threatening
Develops ~ 12-72h after delivery

Question 29

Give 2 risk factors for subgaleal haematoma

Answer 29

Vacuum assisted delivery
(Forceps delivery less so)

Question 30

What is labour triggered by?

Answer 30

Decreased progesterone
Pacemakers in the uterus are suppressed by progesterone
When progesterone levels decrease, the pacemakers fire more, triggering Braxton-Hicks contractions.

Question 31

What is cervical ripening?

Answer 31

Changes from fibromuscular to stretchy material to help baby be pushed out.

Question 32

Why should oxytocin be given in moderation?

Answer 32

Too much oxytocin can cause strong contractions leading to hypoxia fro the fetus.

Question 33

What 4 factors affect the progression of labour?

Answer 33

PASSENGER: big or small?
PASSAGE: shape + size of pelvis
POWER: sufficient regular contractions
POSITION: of foetal head- smallest is AP diameter is OA