Labour and delivery Flashcards
When do labour and delivery normally occur during pregnancy?
Between 37 and 42 weeks gestation
When is labour diagnosed
when painful uterine contractions accompany dilatation and effacement (thinning/shortening) of the cervix
What is the 1st stage of labour
From the onset of true labour to when the cervix is fully dilated
What is the 2nd Stage of labour?
From full dilation of the cervix to the delivery of the baby
What is 3rd stage of labour?
From the delivery of the baby to delivery of the placenta and membranes
Give 4 signs of labour
- regular and painful uterine contractions
- a show (shedding of mucous plug)
- spontaneous rupture of the membranes (not always)
- shortening and dilation of the cervix
What are the phases of Stage 1 of labour and their characteristics?
- Latent phase: 0-3/4cm cervical dilation. Irregular contractions, effacement of cervix
- active (established first stage) phase: 3/4-10 cm cervical dilation, regular, painful contractions
What are Braxton-Hicks contractions, and how do they differ from true contractions?
Braxton-Hicks contractions are occasional irregular contractions of the uterus that are not true contractions. They do not indicate the onset of labour and do not progress or become regular.
Describe the two stages within stage 2 labour
- passive - full dilatation until the head reaches pelvic floor
- active - when the mother is pushing
What are the three factors that influence progress in labour?
- Power - uterine contractions
- Passenger - size, presentation, lie and attitude
- Passage - shape and size of the pelvis and soft tissues
What is the average cervical dilation rate during the active first stage of labour for nulliparous and multiparous women?
- nulliparous women - 1 cm/hr
- multiparous women - around 2 cm/hr
What constitutes a delay in the first stage of labour?
either:
* less than 2 cm of cervical dilation in 4 hours
* slowing of progress in a multiparous woman.
What tool is used to monitor the progress of women during the first stage of labour?
partogram
What key information is recorded on a partogram during labour?
- Cervical dilation (measured by a 4-hourly vaginal examination)
- Descent of the fetal head (in relation to the ischial spines)
- Maternal pulse (1hr), bp, temp and urine output (4hr)
- Fetal HR (every 15 mins)
- Frequency of contractions (half-hourly)
- Status of the membranes, and whether it is stained by blood or meconium
How is failure to progress in labour defined for nulliparous and multiparous women
- nulliparous - labour >20hr
- multiparous - labour >14hr
How long does the second stage of labour typically last?
approximately 1hr multiparous women and 2 hrs in nulliparous women
What interventions may be required when there are problems in the second stage of labour?
- Changing positions
- Encouragement
- Analgesia
- Oxytocin
- Episiotomy
- Instrumental delivery
- Caesarean section
How is the third stage of labour managed actively
- uterotonic drugs - IM oxytocin
- cord clamping and cutting
- controlled cord traction
Why is active management routinely offered to all women during labour?
To reduce the risk of postpartum haemorrhage
How is a delay in the third stage of labour defined?
- > 30 minutes with active management
- > 60 minutes with physiological management
How is failure to progress in labour managed
- Amniotomy - artificial rupture of membranes for women with intact membranes
- Oxytocin infusion - stimulate uterine contractions
- Instrumental delivery
- Caesarean section
What is the target contraction frequency when administering an oxytocin infusion during labour?
aim is for 4–5 contractions per 10 minutes
What are the typical positions of the fetal head during entry into the pelvis and delivery?
The fetal head normally enters the pelvis in the occipito-transverse position and delivers in the occipito-anterior position.
What should be considered if the fetal head remains in the occipito-transverse position after one hour of pushing in the second stage of labour?
Rotation with traction - ventouse
Give 4 RFs for perineal tears
- nulliparity
- large babies
- forceps delivery
- shoulder dystocia
What are the four degrees of perineal tear?
- First-degree: Superficial damage with no muscle involvement
- Second-degree: Involves the perineal muscles, but not the anal sphincter
- Third-degree: Involves the ext and int anal sphincter, but not the rectal mucosa
- Fourth-degree: injury to perineum involving the anal sphincter complex and rectal mucosa
How can third-degree perineal tears be subcategorized?
- 3A: <50% of the external anal sphincter torn
- 3B: >50% of the external anal sphincter torn
- 3C: Both external and internal anal sphincter torn
How are first and second degree perineal tears repaired
- first - usually do not require any sutures
- second - suturing on the ward by a suitably experienced midwife or clinician
How are third and fourth degree perineal tears repaired
require repair in theatre by a suitably trained clinician
What additional measures are taken to reduce the risk of complications after perineal tears?
- Broad-spectrum antibiotics to reduce the risk of infection
- Laxatives to reduce the risk of constipation and wound dehiscence
- Physiotherapy to reduce the risk and severity of incontinence
How is damage to the anal sphincter during an episiotomy avoided?
performing a mediolateral episiotomy.
Define prolonged rupture of membranes
When the amniotic sac ruptures more than 18 hours before delivery
Define prelabour rupture of membranes
The amniotic sac has ruptured before the onset of labour
What is preterm prelabour rupture of membranes
the amniotic sac has ruptured before the onset of labour and before 37 weeks gestation (preterm).
How is preterm prelabour ROM diagnosed
- 1st: sterile speculum exam to look for pooling of amniotic fluid in the posterior vaginal vault
- if no pooling of fluid, test fluid for Placental alpha-microglobin-1 (PAMG-1) or Insulin-like growth factor-binding protein-1 (IGFBP-1)
How is preterm prelabour ROM managed
- admission
- oral erythromycin QDS for 10 days or until in labour
- antenatal corticosteroids to reduce risk of resp distress syndrome
- induction of labour from 37w
why are prophylactic antibiotics given to women with preterm prelabour ROM
Prevent development of chorioamnionitis
Give 2 features of preterm labour with intact membranes
- regular painful contractions
- cervical dilatation
What is the recommended clinical assessment process for preterm labour based on gestational age?
Clinical assessment includes a speculum exam to assess for cervical dilatation
* <30w (29+6) - speculum alone is sufficient for management
* >30w - transvaginal ultrasound to measure cervical length
* >30w - if TVUS unavailable, consider fetal fibronectin. +ve = >50ng/ml
What are the implications of cervical length measurements on ultrasound for preterm labour management?
A cervical length of less than 15 mm suggests that management of preterm labour can be offered; more than 15 mm indicates that preterm labour is unlikely
How is preterm labour managed
- fetal monitoring (CTG and intermittent auscultation)
- tocolysis with nifedipine
- maternal corticosteroids before 35w to reduce neonatal morbidity/ mortality - betamethasone
- IV Mg sulphate before 34w for neuroprotection of the baby
- delayed cord clamping - wait 60 seconds
What is the prophylactic treatment of preterm birth and when is it offered
- Vaginal progesterone and Cervical cerclage
- offered to women with a cervical length <25mm on TVUS between 16 and 24 weeks gestation
What is cervical cerclage
- putting a stitch in the cervix to add support and keep it closed
- stitch is removed when the woman goes into labour or reaches term.
How does progesterone prevent preterm labour
Progesterone has a role in maintaining pregnancy and preventing labour by decreasing activity of the myometrium and preventing the cervix remodelling in preparation for delivery
What are 5 indications for induction of labour?
- Prolonged pregnancy (1-2w after the est due date)
- Preterm prelabour rupture of membranes
- Diabetic mother > 38 weeks
- Pre-eclampsia
- intrauterine growth restriction
- Obstetric cholestasis
- Intrauterine fetal death
What score is used to determine whether to induce labour
Bishop score
What are the 5 components of the bishop score
- fetal station (scored 0 - 3)
- Cervical position (scored 0 – 2)
- Cervical dilatation (scored 0 – 3)
- Cervical effacement (scored 0 – 3)
- Cervical consistency (scored 0 – 2)
How are bishop scores interpretated
- A score of <5 indicates that labour is unlikely to start without induction
- A score of ≥ 8 indicates that the cervix is ripe = high chance of spontaneous labour or a positive response to induction interventions.
What are the possible methods for inducing labour?
- Membrane Sweep - examining finger passing through the cervix to rotate against the wall of the uterus, to separate the chorionic membrane from the decidua. adjunct to full induction
- Vaginal Prostaglandin E2 (PGE2): dinoprostone.
- Oral Prostaglandin E1: Also known as misoprostol.
- Amniotomy with maternal oxytocin infusion
- Cervical Ripening Balloon: Passed through the endocervical canal and gently inflated to dilate the cervix.
When is a membrane sweep typically offered to women during their pregnancy?
offered at 40-42w gestation for nulliparous women and at 41 weeks for multiparous women.
In what situations is a cervical ripening balloon (CRB) used as an alternative method for inducing labour?
- women at higher risk of hyperstimulation
- previous caesarean section
- multiparous woman (para ≥ 3).
What is the preferred method of induction of labor if the Bishop score is ≤ 6 ?
Vaginal prostaglandin or oral misoprostol
What is the preferred method of induction of labor if the Bishop score is > 6 ?
amniotomy and an intravenous oxytocin infusion
Give 3 contraindications for induction of labour
- placenta praevia
- breech, abnormal lie
- abnormal cardiotocograph
What is the main complication of induction of labour
uterine hyperstimulation
What is uterine hyperstimulation
prolonged and frequent uterine contraction causing fetal distress
What complications can arise from uterine hyperstimulation?
- Fetal compromise, including hypoxia and acidosis (due to intermittent interruption of blood flow)
- Emergency caesarean section
- Uterine rupture
How is uterine hyperstimulation managed
- remove vaginal prostaglandins and stop oxytocin infusion
- consider tocolysis
What is instrumental delivery?
A vaginal delivery assisted by a ventouse suction cup or forceps.
Give 3 indications for an instrumental delivery
- Failure to progress in 2nd stage of labour
- Fetal distress
- Maternal exhaustion/ distress
- Control of the head in various fetal positions
What is the relationship between epidurals and instrumental delivery?
There is an increased risk of requiring an instrumental delivery when an epidural is in place for analgesia.
What are some risks to the mother associated with an instrumental delivery?
- Postpartum haemorrhage
- Episiotomy
- Perineal tears (3rd degree)
- Incontinence of the bladder or bowel
- Nerve injury (obturator or femoral nerve)
Give 3 risks to the baby associated with instrumental delivery
- facial nerve palsy (forceps)
- cephalohematoma (ventouse)
- lacerations/ bruising
What is ventouse delivery
- suction cup connected to a handle
- cup goes on baby’s head which allows careful traction to be applied
Describe forceps delivery
- non-rotational or rotational forceps depending on
- the blades go either side of the fetal head allowing traction +/- rotation
What are the 2 main types of caesarean section
- lower segment
- classic - longitudinal incision in upper segment of uterus
Give 5 indications for an elective C-section
- placenta/ vasa praevia
- malpresentations
- pre-eclampsia
- multiple pregnancies
- uncontrolled HIV
- cervical cancer
Describe the 4 categories of caesarean section
Category 1:
* an immediate threat to the life of the mother or baby.
* Decision - delivery time is 30 minutes.
Category 2:
* maternal or fetal compromise which is not immediately life-threatening
* Decision - delivery time is 75 minutes.
Category 3: Delivery is required, but mother and baby are stable.
Category 4: elective caesarean
Give 4 indications for a category 1 C-section
- uterine rupture
- major placental abruption
- cord prolapse
- fetal hypoxia or persistent fetal bradycardia
What are the layers of the abdomen that need to be dissected during a caesarean section?
- Skin
- Subcutaneous tissue
- Fascia / rectus sheath (the aponeurosis of the transversus abdominis and external and internal oblique muscles)
- Rectus abdominis muscles
- Peritoneum
- Vesicouterine peritoneum (and bladder)
- Uterus (perimetrium, myometrium and endometrium)
- Amniotic sac
What are the risks to future pregnancies after a caesarean section
- increased risk of uterine rupture
- increased risk of stillbirth
- increased risk of placenta praevia and placenta accreta
What are the maternal complications of having a caesarean section
- ICU admission/ readmission to hospital
- bladder/ ureter injury
- VTE
- haemorrhage
- wound infections
- endometritis
What complication may occur to the fetus during a caesarean section?
increased risk of lacerations to the fetus
What is the criteria for a planned vaginal birth after Caesarean (VBAC)?
Planned VBAC is appropriate for pregnant women at ≥ 37 weeks gestation with a single previous Caesarean delivery.
* exceptions after counselling by a senior obstetrician
Give 2 contraindications to having a vaginal birth after caesarean
- previous uterine rupture
- classical caesarean scar
What measures can be taken to reduce risks during a caesarean section?
- Administer H2 receptor antagonists (e.g., ranitidine) or PPI before the procedure - for acid reflux and aspiration
- prophylactic Abx to reduce infection risk.
- Administer oxytocin to reduce the risk of PPH
- Provide VTE prophylaxis with LMWH (e.g. enoxaparin)
What anaesthetic is given to women undergoing a caesarean section
- spinal anaesthetic - local anaesthetic (e.g lidocaine) into CSF at lower back
