Labour Flashcards
How many labours are induced and what do they require?
Approx 1 in 5 pregnancies are induced (artificially starting labour)
- Need fetal monitoring
- Need for cervical ripening=Prostaglandins (pharmacological) or Balloon (mechanical)
What is induction of labour?
When an attempt is made to instigate labour artificially using medications and/or devices to “ripen cervix” followed usually by artificial rupture of membranes (performing an amniotomy)
What is the BISHOP’S SCORE used for?
To clinically assess the cervix
The higher the score the more progressive change there is in the cervix & indicates that induction is likely to be successful
When can an amniotomy be performed?
Once cervix has dilated and effaced
What Bishop score is considered favourable for amniotomy?
7 or more
What is an amniotomy?
Artificial rupture of the fetal membranes usually using a sharp device (e.g. amniohook)
Once an amniotomy is performed what is IV OXYTOCIN used for?
Can be used to achieve adequate contractions (unless contractions spontaneously start) - aim for 4-5 contractions in 10 minutes
What are the indications for the induction (IOL)?
Diabetes
Post dates – Term + 7 days (Especially as increase over 41 weeks gestation-increasing risk of still birth)
Maternal need for planning of delivery e.g. on treatment for DVT
Foetal reasons e.g. growth concerns, oligohydramnios
Social / maternal request
What may cause inadequate progress in labour?
Inadequate uterine activity (powers)
Cephalopelvic disproportion (CPD) (passages)
Other reasons for obstruction e.g. fibroid (passages)
Malposition (passenger)
Malpresentation (passenger)
What is labour defined by?
Regular uterine contractions, progressive effacement & dilation of the cervix & descent of presenting part (baby)
Progress in labour is evaluated by a combination of abdominal & vaginal examinations to determine what?
-Cervical effacement
-Cervical dilation
-Descent of the fetal head through the maternal pelvis
For 1) Primigravid women & 2) Parous woman in the active 1st stage of labour suboptimal progress is defined as cervical dilation of less than what?
1) <0.5cm per hr
2) <1cm per hr
What happens if contractions are inadequate?
Fetal head will not descend & exert force on the cervix & the cervix will not dilate
How can the strength and duration of the contractions be increased?
Giving a synthetic IV oxytocin to the mother
Why is it important to exclude an obstructed labour in circumstances of inadequate uterine activity?
As stimulation of an obstructed labour could result in a ruptured uterus
What is cephalopelvic disproportion (CPD)?
Fetal head is in the correct position for labour but is too large to negotiate the maternal pelvis to be born
Caput (soft tissue swelling on head) &
Moulding (foetal skull bones start to cross over each other) develop
Is a degree of caput & moulding normal in labour?
Yes
Caput (soft tissue swelling on head) &
Moulding (foetal skull bones start to cross over each other)
What is malposition in labour and what occurs?
Involves the fetal head being in a suboptimal position for labour and ‘relative’ CPD occurs
Occipito-posterior (OP) & Occipito-transverse (OT)
Occipito-anterior position=optimal position
OT-babys not typically born in this position
How can tell of position of babies head?
Vaginal exam to feel for babies head-use fontanelles to guide
What is Vasa praevia?
Bleeding from foetal vessels that are abnormally placed in the amniotic sac
Why is it important to avoid causing too many contractions (Uterine Hyper-stimulation)?
Can result in fetal distress due to insufficient placental blood flow
What are the main causes of foetal distress?
Hypoxia, infection & also rare occurrences such as cord prolapse, placental abruption & vasa praevia
In many cases of suspected fetal distress no cause is found
There are 4 ways that foetal monitoring can be carried out. What are they?
- Intermittent auscultation of the foetal heart
- Cardiotocography (CTG)
- Fetal blood sampling
- Fetal ECG
How is fetal blood sampling carried out and when is it used?
Speculum used to take fetal scalp blood sample
Used when abnormal CTG
Foetal blood sampling provides a direct measurement from baby of what?
- pH & base excess
- Lactic acid
pH gives a measure of likely hypoxaemia
What forms of assisted or operative delivery are available?
- Instrumental deliveries (forceps/ventouse)
- Planned (elective) CS
- Emergency CS
When can CS be performed in labour?
Can be performed at any time in labour-risk of PPH increases when performed at full dilatation
What are 3rd stage complication examples?
- Retained placenta (If after 60 mins placenta not out-would offer manual removal of placenta)
- PPH (4 Ts)
- Tears
Graze
1st degree
2nd degree
3rd degree – involving anal sphincter complex
4th degree – involving rectal mucosa
What are the 4 Ts associated with PPH?
TRAUMA
TONE
THROMBIN (clotting abnormal)
TISSUE (retained preg tissue)
Labour problems are common especially in ..?..
Primigravid women
What in its simplest terms are labour problems due to
’ The Passage, The Powers or The Passenger’
When may operative vaginal birth or CS be necessary?
When problems occur in labour to prevent fetal & maternal morbidity & mortality
Labour complications can be context specific: Give examples of this?
Place of birth, Skilled birth attendance
Fetal & Maternal monitoring in labour (e.g. labour progress, observations)
Access to; medical care in labour (e.g. long transfer in extremis), CS (e.g. in a tertiary hospital only), assisted vaginal birth (e.g. where medical staff work), medical care in context of birth after CS
Prevalence and severity of female genital mutilation
What are the key labour complications that occur where healthcare resource is limited?
- Prolonged labour leading to: uterine rupture, obstetric fistula, PPH
- Untreated HT disorders of pregnancy (may or may not be labour-related)
- Infection (may be intrapartum or post-partum)
- Intrauterine death, preterm birth, neonatal death
What are the top maternal mortality causes in low income settings?
- PPH
- Infection post-birth
- High BP complications
What are some context specific risk factors for adverse outcomes?
Education level & Socioeconomic status
Intimate partner violence
Cultural practices e.g. FGM
Long-distance travel to facility
Antenatal care attendance/follow-up
Multiparity
Twin pregnancy
Lack of women’s involvement in decision-making
When can uterine rupture occur & what can it lead to?
Can happen after a very prolonged labour
Can lead to abrupt maternal haemorrhage & foetal hypoxia
What are the risk factors for uterine rupture?
- Prolonged labour
- Previous uterine surgery (could be previous CS or myomectomy)
(Can happen particularly in women of high parity when labour has been long)
How is an obstetric fistula formed?
During prolonged labour, compression of soft tissues between the babys head & womans pelvis cuts off blood flow to the bladder or rectum. As a result, tissue dies, leaving a hole/fistula
How are fistulas managed?
Repair- complex & may only be provided by charity organisations
Requires extensive experience & surgical skills
When does morbidly adherent placenta arise?
Arises when placenta does not attach normally in development but attaches firmly or even invades through uterine wall- life threatening haemorrhage may occur at births- many such births require hysterectomy to stop bleeding
This condition is more common after repeated caesarean births
Normal placenta is separated form uterine wall by a what?
Fine fibrinous layer
What can be used in the prevention of labour complications?
- Oxytocin injections
- Good hygiene
- Early treatment of infection
- BP control & Magnesium Sulphate in severe pre-eclampsia
(Education, Access to health facilities,
Tackling poverty, cultural practices, low quality health services)
What is the process of normal labour?
Foetus, placenta & membranes are expelled via birth canal and is spontaneous
When does labour normally occur and what does it result in?
37-42 weeks gestation
Spontaneous vaginal birth (SVD)
How does the foetus present in normal labour?
By the vertex (head down)
What triggers labour to start?
Triggered by paracrine & autocrine signals generated by maternal, foetal & placental factors which interplay
What key physiological changes must occur to allow for expulsion of the foetus?
o Cervix softens
o Myometrial tone changes to allow for coordinated contractions
o Progesterone decreases whilst oxytocin & prostaglandins increase to allow for labour to initiate
What are the 3 stages of labour?
1st= Early/latent phase, active first stage & transition
2nd= Passive, active
3rd= Active or physiological
What can be the longest part of labour?
Latent phase - Irregular contractions
Cervical changes & dilation up to 4cm
Length of active labour is what and what does it involve?
Can vary from 8-12 hrs
- Regular, painful contractions
- Cervix is 4-10 cm
What may be experienced in transition part of the first stage of labour?
May experience physical changes such as shaking, vomiting or the need to empty bowels
May express that they can no longer cope/in need of more pain relied
Cervix is 8-10cm
What is the second stage of labour and what elements can it have?
Full dilation to birth
*Passive second stage of labour-no involuntary expulsive contractions
*Active second stage of labour-see presenting part visible or there are expulsive contractions or there is encouraged maternal effort
What is the length of the second stage of labour?
Varies between 2-3hrs depending on if woman is nulliparous or multiparous
What is the 3rd stage of labour?
From birth of the baby to the expulsion of the placenta and membranes
What is involved in the physiological management of the third stage of labour?
No uterotonics used or cord clamping until pulsation has stopped- placenta is delivered by maternal effort
What is the active management of the third stage of labour?
Uterotonic drugs, optimal cord clamping & deliver by controlled cord traction
What are the mechanisms of labour?
-Engagement & descent
-Flexion
-Internal rotation of head
-Crowning & extension of head
-Restitution (twist of the neck to correct internal position)
-Internal rotation of the head & external rotation of the head
-Lateral flexion of shoulders (aid birth of baby by giving gentle axial traction)
Is there always stress exerted on the foetus in labour?
Yes, stress is exerted onto the fetus regardless of it being a spontaneous or augmented labour therefore it is important to monitor the foetal heart
Monitoring whether it is intermittent auscultation or continuous monitoring is dependant on what?
Woman’s risk assesment
How can intermittent auscultation be carried out?
Can be done using a Pinards stethoscope or a handheld doppler
How is continuous monitoring carried out?
Cardiotocograph (CTG)
What is the description of a normal foetal HR?
~100-160 bpm with good variability (>5bpm) & accelerations (15bpm)
How can a woman be monitored in labour?
o Maternal observations
o Abdominal palpation
o Vaginal examination
o Monitoring of liquor (colour, meconium, blood stained)
o Palpation of contractions
o External signs e.g Rhomboid of Michaelis and anal cleft line
All women will experience labour differently, and there are many non-pharmacological and pharmacological options that they can utilise: What are they?
Maternal position and mobility
Breathing and hypnobirthing techniques
Massage
Aromatherapy
TENS
Oral analgesia
Water
Entonox
Opioids
Remifentanil PCA
Epidural
