Labour and birth

Question 1

Explain the process of the initiation of labor

Answer 1

There is the inhibition of pro-pregnancy factors and the activation of pro-labour factors:

Pro-pregnancy: Progesterone, nitric oxide, catecholamins, relaxin.

Pro-labour: Oestrogens, oxytocin, prostaglandins, corticotrophin-releasing hormone and inflammatory mediators

Question 2

What is the role of progesterone in pregnancy

Answer 2

It is derived from the corpus luteum for first 8 weeks then the placenta.
It promote uterine smooth muscle relaxation, reduced inflammation and decreases cytokine production

Question 3

What is the role of nitric oxide in pregnancy?

Answer 3

Free radicle which may be involved in cervical ripening.

Question 4

What is the role of catecholamines in pregnancy

Answer 4

It acts indirectly on myometrial cells to alter contractility, May indirectly cause uterine muscle relaxation.

Question 5

Describe the role of oxytocin in pregnancy?

Answer 5

Potent stimulator of uterine contractility. Increases frequency and force of contractions.
Increase in oxytocin receptor levels as term approaches but not amount of oxytoxin.

Question 6

Describe the role of prostaglandins in pregnancy

Answer 6

Levels increase prior to onset of labour. They promote cervical ripening and stimulate uterine contractility

Question 7

What is the role of inflammatory cells in pregnancy?

Answer 7

Inflammatory cells are recruited to fetal membranes, uterus and cervix at the onset of labour. Cytokines are produced leading to pro-inflammatory factors. These contribute to cervical ripening and membrane rupture

Question 8

Explain cervical ripening

Answer 8

During the latter stages of pregnancy the cervix softens and begins to efface so delivery can occur.
Prostaglandins increase cervical ripening by inhibiting collagen synthesis and stimulates collagenase to break down collagen.
As the concentration of collagen decreases, the cervix becomes softer and ready to dilate.

Question 9

How is cervical ripening assessed

Answer 9

Bishop’s score which looks at cervical dilation, length of cervix, station of presenting part, consistency (firm, medium or soft), and position.`

Question 10

What is effacement and dilation

Answer 10

Effacement is shortening and thinning of the cervix.
Dilation is dilation of the external os.
Prim women tend to efface before they dilate.
Parous women can efface and dilate simultaneously.

Question 11

What are the three stages of labour?

Answer 11

1 - Onset of labour until full dilation.
a) latent first stage: painful contractions AND some cervical change including effacement and dilation up to 4cm.
b) Established first stage: Regular painful contractions and progressive dilation from 4cm
2 - Full dilation until delivery of baby.
3 - Delivery of baby until delivery of placenta

Question 12

Explain the process as the babies head and shoulders are delivered

Answer 12

Head descends and engages. As it reaches pelvic floor the occiput rotates to OA. Head delivers by extension, foetal head bones overlap to allow head to pass through pelvis. Shoulders rotate to the AP diameter and head follows.
Anterior shoulder delivers with lateral flexion.
Posterior shoulder then delivers.

Question 13

Explain the different postitions of the fetal head

Answer 13

Right or left occipitoposterior - occiput of head is facing posteriorly to mum.

Right or left occipitoanterior - occiput is anterior to face is posterior.

Left or right occipitotransverse - occiput is transverse

Question 14

What are the risks of pre-labour rupture of the membranes?

Answer 14

Ascending infection, chorioamnionitis and group B streptococcus neonatal infection.
Wait 24 hours to see if labour starts, if not then should induce.

Question 15

What is the initial assessment of a woman in labour?

Answer 15

Review history/notes/background.
Determine risk
Ask about strength and frequency of contractions.
Ask about pain and options for relief.
Do a set of obs and urinalysis.
Ask about PV blood, liquor, show (mucousy, sticky blood mixed with discharge), mucus
Ask about fetal movements
Palpate abdomen - Fundal height, baby’s lie, position and engagment of presenting part.
Auscultate fetal heart rate for 1min after contractions.
Vaginal examination

Question 16

What can be felt on PV exam during labout?

Answer 16

Presence/absence of meconium - may suggest fetal distress
Dilation of cervix,
Station of presenting part,
Position of head,
Presence of caput or moulding.

Question 17

Explain features of caput and moulding

Answer 17

Caput succedaneum - subcut oedema of scalp (+,++ or +++)
Moulding - change in shape of foetal head which occurs during labour so it can pass through birth canal. + if bones opposed. ++ if overlaping but can be reduced. +++ if overlap and cannot be reduced.

Question 18

Describe features of meconium

Answer 18

Commonly seen as baby passes meconium during or pre labout. Normal is thin and green/brown.
Thick, green, meconium can be sign of fetal hypoxia or acidosis. If babies become hypoxic or acidotic they may gasp in utero and aspirate meconium (meconium aspiration syndrome)

Question 19

What is the station?

Answer 19

Presenting part of the baby with respect to ischial spines

Question 20

What are some factors to consider where a birth is high risk?

Answer 20

Women’s PMH/underlying conditions.
Previous intrapartum/postnatal issues,
Any antenatal issues,
Any current issues, eg, bleeding, meconium, fetal movements, infective symptoms.
Is labour spontaneous or induced?
Maternal observations,
Previous C-sections,
Multiple pregnancies?
Any fetal issues?
Analgesia - epidural?
Stage of labour

Question 21

What is the monitoring done in labour?

Answer 21

Partogram
Documentation of frequency of contractions, every 30mins.
Hourly pulse,
4 hourly temp, BP and PV exams,
Frequency of passing urine,
Fetal monitoring (intermittent auscultation or CTG)

Question 22

What additional monitoring is required in the 2nd stage of labour?

Answer 22

Vaginal exam is offered every hour.
Hourly blood pressure,
Auscultate fetal heart beat immediately after contraction for at least one min, at least every 5 mins.

Question 23

What is the normal progression of the active phase in the 1st stage of labour?

Answer 23

Change in cervix by 0.5/1cm every hour in a primi. Diagnose delay if dilation is less than 2cm in 4 hours.
Change by 1cm in multiparous woman. Diagnose delay if dilation is less than 2cm in 4hr or slowing of progress.

Question 24

What is the normal progress in the 2nd stage of labour?

Answer 24

Primigravida - Birth expected within 3 hours from the start of second stage. Diagnose delay when it has lasted 2 hours (suspect after 1).

Multiparous - Birth expected within 2 hours. Diagnosed delay if longer than 1 hour. Suspect after 30mins.

Things tend to slow down with epidural

Question 25

How do you manage delay in the 1st stage of labour?

Answer 25

Offer amniotomy (rupture of membranes) then reassess 2 hours later. Would expect at least 1cm further dilation. Consider oxytocin augmentation.

Question 26

How do you manage delay in labour in the second stage?

Answer 26

May offer assisted birth with instruments or a caesarean. Oxytocin can be considered if uterine activity is suboptimal. Consider episiotomy if rigid perineum

Question 27

What are some causes of delay in labour

Answer 27

Uterine activity, Obstructed labour, Fetal malposition, Caput or moulding

Question 28

What are examples of fetal malpresentation?

Answer 28

Breech - options: ECV, birth breech, Caesarean. Brow - Widest diameter so cannot deliver. Face - Can deliver but may be prolonged. May have bruising and oedema to face

Question 29

Explain features of malpostion

Answer 29

This is an abnormal position of vertex relative to maternal pelvis, eg, Ocipitoposterior. This may result in a longer labour and may require oxytocin.

Question 30

Describe the process of the 3rd stage of labour

Answer 30

Placental separation is recognised by cord lengthening and gush of dark red blood PV. Placenta is delivered by controlled cord traction with uterine fundal guarding. There is risk of uterine inversion

Question 31

Explain the physiological and active methods to the 3rd stage of labour

Answer 31

Physiological - no use of uterotonic drugs, no clamping of cord until pulsation has stopped, delivery of placenta by maternal effort. Increased risk of PPH and transfusion. Active - Oxytocin +/- ergometrine, deferred clamping and cutting of the cord by at least 1m but no longer than 5min, controlled cord traction, increased nausea and vomiting.

Question 32

explain features of delay in the 3rd stage of labour

Answer 32

Defined at >30mins in active and 1 hour in physiological/passive. This has an increased risk of PPH as uterus cannot contract. MUST get IV access, G&S and xmatch. Requires manual removal of placenta which requires either regional or general anaesthesia.

Question 33

What is precipitate labout?

Answer 33

Explusion of the fetus within less than 2-3 hours since the onset of contractions. It can be caused by uterine overactivity, placental abruption or use of oxytonics. Risks of fetal distress and uterine rupture

Question 34

What are the indications for an episiotomy and how is it repaired?

Answer 34

Rigid perineum which is preventing delivery. If a tear is imminent. Most instrumental deliveries. Suspected fetal compromise, Shoulder dystocia, Make sure you give local anesthetic infiltration if no epidural and cut in the right mediolateral direction Repair - Examine for 3rd/4th degree tears, use rapidly absorbable synthetic suture, give analgesia and icepacks

Question 35

What are the indications of a induction of labour?

Answer 35

Prolonged pregnancy, Maternal diabetes, Twin pregnancy, PROM, FGR, Hypertensive disorders of pregnancy, Deteriorating maternal medical conditions, Maternal request, Reduced fetal movements.

Question 36

What are the contraindication to an induction?

Answer 36

Situations where vaginal delivery is contraindicates. Risk of hyperstimulation in those with previous labour precipitate. Caution in those with previous caesarean or uterine surgery.

Question 37

What are the methods for induction of labour?

Answer 37

If Bishops score < 6 then can use prostaglandins (inserted into posterior fornix) or a cooks balloon which puts pressure on the internal os and leads to local prostaglandin release. If Bishops score > 6 then do ARM or syntocinon (after ARM) which is synthetic oxytocin.

Question 38

What are the risks associated with inducing labour?

Answer 38

Mainly associaed with use of oxytocics. There is an increase in operative vaginal rates, risk of hyperstimulation, labour can be more painful and there is a risk of uterine rupture.

Question 39

What is augmentation of labour?

Answer 39

Way of accelerating labour which has already been started. Either ARM or oxytocin.