Labour and Delivery Flashcards
Define labour?
When do labour and delivery normally occur?
Labour may be defined as the onset of regular and painful contractions associated with cervical dilation and descent of the presenting part
Between 37 and 42 weeks gestation
What are the three stages of labour?
First stage - from onset until 10cm cervical dilation
Second stage - from 10cm cervical dilation until delivery of baby
Third stage - from delivery of baby to delivery of placenta
What changes to the cervix happen in the first stage of labour?
Cervical dilation - opening up
Effacement - getting thinner
Mucus plug falls out creating space for baby to pass through
What are the 3 phases to the first phase of delivery?
Latent phase = from 0 to 3cm - progresses at 0.5cm per hour - irregular contractions
Active phase = from 3 to 7cm - progresses at 1cm per hour - regular contractions
Transition phase = from 7 to 10cm - progresses at 1cm per hour - strong and regular contractions
What are Braxton-Hicks contractions?
Occasional irregular contractions of the uterus (felt during 2nd and 3rd trimester)
Not indicating the onset of labour - staying hydrated and relaxing reduces these contractions.
What are the signs of labour?
Show (mucus plug from the cervix)
Rupture of membranes
Regular, painful contractions
Dilating cervix on examination
What are the latent first stage of labour and the established first stage of labour?
Latent first stage = painful contractions, changes to the cervix, with effacement and dilatation up to 4cm
Established first stage = regular, painful contractions, dilatation of the cervix from 4cm onwards
What is prematurity?
Birth before 37 weeks gestation
When are babies considered non-viable?
Before 23 weeks gestation
23-24 weeks: baby not considered for resuscitation if the do not not show signs of life
24 weeks onwards: increased chance of survival
What is the WHO classification of prematurity?
Under 28 weeks: extreme preterm
28 – 32 weeks: very preterm
32 – 37 weeks: moderate to late preterm
What are the 2 options for prophylaxis of pre-term labour? Who is it offered to?
Vaginal progesterone- given via pessary or gel; progesterone maintains pregnancy and prevents labour by decreasing activity of the myometrium and preventing cervix remodelling in preparation for delivery
- Offered to woemn with a cervical length <25mm on vaginal USS between 16 and 24 weeks gestation
Cervical cerclage- stitch in cervix to keep it closed- removed when woman goes into labour/ reaches term
- Offered to woemn with a cervical length <25mm on vaginal USS between 16 and 24 weeks gestation who have had a previous premature birth or cervical trauma eg colposcopy or cone biopsy
What is preterm prelabour rupture of membranes?
(PPROM)
Occurs in ~2% pregnancies but is associated with around 40% preterm deliveries
Where the amniotic sac ruptures before the onset of labour and in a preterm pregnancy (under 37 weeks gestation)
How is P-PROM diagnosed?
Speculum examination revealing pooling of amniotic fluid in the posterior vaginal vault of vagina - no tests are required
Digital examination avoided- risk of infection
USS- may reveal oligohydramnios
What tests can be used to confirm the diagnosis of P-PROM?
- Insulin-like growth factor-binding protein-1 (IGFBP-1)- present in amniotic fluid, can be tested for in vaginal fluid if there is doubt about rupture of membranes
- Placental alpha-microglobin-1 (PAMG-1)- similar alternative as above
What is the management of P-PROM? What are some potential complications?
Admission
Regular observations to ensure chorioamnionitis is not developing
Prophylactic antibiotics given to prevent chorioamnionitis
- Erythromycin 250mg qds for 10 days or until labour is estabilished if within 10 days
Antenatal corticosteroids to reduce the risk of RDS
Induction of labour may be offered from 34 weeks -there is a trade-off between increased risk of maternal chorioamnionitis with a decreased risk of respiratory distress syndrome as the pregnancy progresses
COMPLICATIONS
- Fetal: prematurity, infection, pulmonary hypoplasia
- Maternal: chorioamnionitis
What antibiotics are recommended to prevent chorioamnionitis?
Erythromycin 250mg 4 times daily for 10 days or until labour is established if within 10 days
What is preterm labour with intact membranes? How is this diagnosed?
Preterm labour with intact membranes with regular painful contraction and cervical dilatation, without rupture of the amniotic sac
- Speculum exam to assess for cervical dilatation
- If > 30 weeks: offer TV USS to assess cervical length
- If cervical length < 15mm, mx of preterm labour can be offered
- If > 15mm, preterm labour is unlikely
- Alternative to vaginal USS: fetal fibronectin found in vagina during labour, if <50ng/ml then preterm labour is unlikely
What is included in the management of preterm labour?
Fetal monitoring (CTG or intermittent auscultation)
Tocolysis with nifedipine: nifedipine is a calcium channel blocker that suppresses labour
Maternal corticosteroids: can be offered before 35 weeks gestation to reduce neonatal morbidity and mortality
IV magnesium sulphate: can be given before 34 weeks gestation and helps protect the baby’s brain
Delayed cord clamping or cord milking: can increase the circulating blood volume and haemoglobin in the baby at birth
What is tocolysis?
- Medication to stop uterine contractions - nifedipine, a CCB, is the medication of choice for tocolysis
- Alternative- atosiban, oxytocin receptor antagonist
- Can be used between 24 and 33+6 weeks; Can’t be used > 34 weeks
- Short term measure- < 48 hrs
When and why are antenatal steroids given?
Develop the fetal lungs and reduce respiratory destress syndrome after delivery
Used in women with suspected preterm labour of babies less than 36 weeks gestation
What is IV magnesium sulphate given for? Why is close monitoring required?
Protect the fetal brain during premature delivery. Reduces the risk and severity of cerebral palsy.
Given as a bolus within 24 hrs of delivery of preterm babies of <34 weeks gestation.
Infusion for up to 24hrs after birth
Close monitoring for toxicity required- 4 hourly- tendon reflexes (patella)
Signs of toxicity- reduced RR, reduced BP, absent reflex
What is induction of labour?
Use of medication to stimulate the onset of labour
Occurs in ~20% pregnancies
When is induction of labour offered?
Between 41 and 42 weeks gestation
Indications
- Prelabour premature rupture of membranes where labour does not start
- Prolonged pregnancy eg 1-2weeks after EDD
- FGR
- Diabetic mother > 38 weeks
- Pre-eclampsia
- Rhesus incompatibility
- Obstetric cholestasis
- Intrauterine fetal death
What is the Bishop Score?
Scoring system used to determine whether to induce labour
- A score of < 5 indicates that labour is unlikely to start without induction
- A score of ≥ 8 indicates that the cervix is ripe, or ‘favourable’ - there is a high chance of spontaneous labour, or response to interventions made to induce labour
- Components: cervical nposition, cervical dilation, cervical effacement, cervical consistecy, fetal station
- PDECS
What are the options for induction of labour?
- Membrane sweep- should induce labour within 48 hrs, typically offered from 40 weeks in ANC
- Vaginal prostaglandins E2 (dinoprostone) (PGE2)- NICE say this is the preferred method of induction unless there are specific contraidnicates/ reasons to not use
- Cervical ripening ballon (CRB)- passed through endocervical canal and gently inflated to dilate cervic
- Artifical rupture of membranes - amniotomy
- Maternal oxytocin infusion
- Oral mifepristone (anti-progesterone) plus misoprostol- intrauterine death
What is a membrane sweep?
Inserting a finger into the cervix to stimlate the cervix: finger passing through the cervix to rotate against the wall of the uterus, to separate the chorionic membrane from the decidua
Can be performed in antenatal clinic by midwife and if successful should produce the onset of labour within 48 hours
Seen as an adjunct to the full induction of labour.
Used from 40 weeks gestation to attempt to initiate labour in women over their EDD
What does a vaginal prostaglandin E2 (dinoprostone) involve?
Inserting a gel, tablet (Prostin) or pessary (propess) into the vagina.
The pessary is similar to a tampon, slowly releasing local prostaglandins over 24 hours.
Stimulates uterus and causes the onset of labour.
Usually done in the hospital setting so the woman can be monitored before being allowed home to await the full onset of labour.
What is a cervical ripening ballon?
Silicone ballow which is inserted into the cervix and gently inflated to dilate the cervix
Used ias an alternative where vaginal prostaglandins are not preferred, usually in women with a previous C-section or where vaginal prostaglandins have failed or multiparous women (para 3)
What is the artificial rupture of membranes?
With an oxytocin infusion can also be used to induce labour.
This is used there there are reasons not to use vaginal prostaglandins, can be used also to progress the induction of labour after vaginal prostaglandins have been used
What are the two means for monitoring during the induction of labour?
Cartiotocography (CTG) to assess the fetal heart rate and uterine contractions before the induction of labour
Bishop score before and during the induction of labour to monitor the progress
What is the ongoing management of induction of labour? Discuss options when there is slow/ no progress
Most women will give birth within 24 hours of the start of induction of labour
The options where there is slow or no progress include:
- Further vaginal prostaglandins
- Artificial rupture of membranes and oxytocin infusion
- Cervical ripening balloon (CRB)
- Elective caesarean section
What is the main complication of using vaginal prostaglandins to induce labour? How is it managed and what are the potential consequences
Uterine hyperstimulation - causing fetal distress and compromise
Refers to prolonged and frequent uterine contractions - sometimes called tachysystole
Potential consequences-
- Itermittent interruption of blood flow to the intervillous space over time may result in fetal hypoxemia and acidemia
- Emergency CS
- Uterine rupture (rare)
Mx-
- Remove vaginal prostaglandins or stop oxytocin infusion
- Tocolysis with terbutaline
What is the criteria for uterine hyperstimuation?
Varies between guidelines, two criteria often used are:
- Individual uterine contractions lasting more than 2 minutes in duration
- More than 5 uterine contractions every 10 minutes
What does cartiotocography do?
Measures the fetal heart rate and the contractions of the uterus
What is oxytocin? Describe its use in obs and gynae?
Hormone secreted by the posterior pituitary gland (produced in the hypothalamus). Stimulates ripening of the cervix & contractions of uterus during labour and delivery, plays a role in lactation during BF
Role of infusions
- Induce labour
- Progress labour
- Improve frequency & strength of uterine contractions (most receptors in myometrium)
- Best used where membranes have ruptured, whether spontaneously or after amniotomy
- Has been shown to increase cervical prostaglandin levels
Syntocinon is a synthetic version of oxytocin that is used in the active management of third stage of labour. It stimulates the contraction of the uterus reducing the risk of postpartum haemorrhage. It is also used to induce labour.
What is ergometrine? Side effects?
Medication to stimulate smooth muscle contraction, both in uterus and blood vessels
Derived from ergot plants
Useful for delivery of the placenta and reduces post partum bleeding
- used as an alternative to oxytocin in the active management of third stage of labour. By constricting vascular smooth muscle of the uterus it can decrease blood loss.
- (Only used after delivery of baby, not in 1st/2nd stage)
- S/E: htn, diarrhoea, vomiting, angina (coronary artery spasm)
- Avoid in eclampsia, used in caution in pts with htn
What is syntometrine? When is it used?
Combination drug containing oxytocin (syntocinon) and ergometrine
Used for prevention/treament of PPH
Role of prostaglandins during labour?
Dinoprostone- prostaglandin E2 used for induction of labour
Comes as vaginal pessary/ tablet/ gel
Prostaglandins stimulate uterine contraction and ripen cervix prior to delivery
When are NSAIDs used in gynaecology? Why should they be avoided in pregnancy?
Treating dysmenorrhoea (painful periods) as they reduce painful cramping (e.g. ibruprofen and mefenamic acid)
- NSAIDs inhibit action of prostaglandins
- Prostaglandins act as vasodilators and lower bp
- NSAIDs can increase BP
What is misoprostol?
Prostalandin analogue (binds to prostaglandin receptors and activates them)
Mifepristone is used in combination with misoprostol to terminate pregnancies.
Also used for induction of labour after intrauterine fetal death
What type of drug is nifedipine? Uses in pregnancy?
CCB which acts to reduce smooth muscle contraction in blood vessels and the uterus
2 uses in pregnancy- reduce bp in htn and pre-eclampsia; tocolysis in premature labour where it suppresses uterine activity and delays onset of labour
What is terbutaline?
Beta-2-agonist similar to salbutamol
Acts on s.m. of uterus to suppress contractions
Used for tocolysis in uterine hyperstimulation
What is carboprost?
Synthetic prostaglandin analogue - stimulating uterine contraction
Given as deep IM injection in PPH where ergometrine and oxytocin have been inadequate
Avoid/ caution in asthma- can cause life-threatening attack
What is tranexamic acid?
Antifibrinolytic which reduces bleeding (binds to fibrinogen and prevents it from converting to plasmin)
Used in prevention and treatment of PPH
What is progress in labour influenced by?
The 3 Ps:
Power (uterine contractions)
Passenger (size, presentation and position of the baby)
Passage (the shape and size of the pelvis and soft tissues)
What suggests delay in the 1st stage of labour? What are the main causes?
Less than 2cm of cervical dilatation in 4 hours
Slowing of progress in a multiparous women
Causes:
- Most common: inefficient uterine actions (power)
- Malposition/ malpresentation of fetus (passenger)
- Inadequate pelvis (passage)
- Or, a combo of the above
What is the second stage of labour?
From 10cm dilation of the cervix to delivery of the baby - success depends on: the three Ps
How is delay in the second stage classified?
When the active second stage (pushing) lasts over:
2 hours in a nulliparous woman
1 hour in a multiparous woman
Factors affecting delay in second stage of labour and how these can be overcome?
- POWER: strength of uterine contractions
- Weak contractions- give oxytocin infusion
- Passenger: size, attitude, lie, presentation
- Passage
- Change positions
- Encouragement
- Analgesia
- Episiotomy
- Instrumental delivery
- CS
What is a delay in the third stage of labour defined as?
More than 30 minutes with active management
More than 60 minutes with physiological management
What does active management of the third stage of labour involve?
- Intramuscular syntometrine (ergometrine 0.5mg + oxytocin 5IU) or oxytocin 10IU IM (this is preferred by NICE due to fewer side effects) is given as the anterior shoulder of baby is born
- A dish is placed at the introitus to collect the placenta and any blood loss, and the left hand is placed on the abdomen over the uterine fundus.
- As the uterus contracts to 20-wk size, the placenta separates from the uterus through the spongy layer of the decidua basalis.
- The uterus will then feel globular and firmer, the cord will lengthen, and there is often a trickle of fresh blood (separation bleeding).
- Controlled cord traction (CCT)- Applied with the right hand, whilst supporting the fundus with the left hand (Brandt–Andrew’s technique)
(exclude multiple pregnancy before giving uterotonixcs)
Physiological mx-
- No Syntometrine® or oxytocin is given.
- Cord is allowed to stop pulsating before it is clamped and cut. NICE (2014) recommends that the cord should not be clamped at least for 1min, unless the baby’s heart rate is <60bpm and not picking up.
- Currently equipment are available that can be kept by the side of the mother to help resuscitation with the cord intact.
- Cord should be clamped before the end of 5mins.
- The placenta is delivered by maternal effort alone.
What are the management options for failure to progress in labour?
Amniotomy, also known as artificial rupture of membranes (ARM) for women with intact membranes
Oxytocin infusion
Instrumental delivery
Caesarean section
What is used first line in failure to progress during labour?
Oxytocin to stimulate contractions during labour - started at a low rate and then titrated up at intervals of at least 30 minutes as required
When using oxytocin in labour, what is the number of contractions to aim for?
4-5 contractions per 10 minutes (too may can cause fetal compromise as it doesn’t have the time to recover between contractions)
What can help with managing pain in labour (without medications)
Understanding what to expect
Having good support
Being in a relaxed environment
Changing position to stay comfortable
Controlled breathing
Water births may help some women
TENS machines may be useful in the early stages of labour
What pain relief is used in labour?
Paracetamol (codeine may be added for additional effect - NSAIDs are avoided)
Gas and Air (entonox) - mixture of 50% nitrous oxide and 50% oxygen to give short term pain relief during contraction
- Can cause lightheadedness, sleepiness, nausea
IM pethidine or diamorphine
- Opioids
- May help with anxiety & distress
Pt controlled analgesia- remifentanil
- Careful monitoring, input from anaesthetist
- Access to naloxone for respiratory depression
- Access to atropine for bradycardia
Epidural
- Small catheter into epidural space in lower back
- Local anaesthetic medications infused through into the epidural space here they diffuse to the surrounding tissues and through to the spinal cord where they have an analgesic effect
- Levobupivacaine, bupivacaine, usually mixed w/ fentanyl
- Adverse effects: headache after insertion, hypotension, motor weakness in legs (assessment urgently by anaesthetist to see if the epidural is in the correct place not the SA space), nerve damage, prolonged 2nd stage, increased probability of instrumental delivery
What is cord prolapse?
When the umbilical cord descends nelow the presenting part of the fetus and through the cervix, into the vagina
Occurs in 1/500 deliveries
Left untreated, this can lead to compression of the cord or cord spasm, which can cause fetal hypoxia and eventually irreversible damage or death.
Describe some risk factors for cord prolapse
Most significant- Fetus is in an abnormal lie after 37 weeks gestation (unstable, transverse or oblique)
Others-
- Prematurity
- Multiparity
- Polyhydramnios
- Twin pregnancy
- Artificial rupture of membranes
When should an umbilical cord prolapse be suspected and how is it diagnosed?
Signs of fetal distress on the CTG - fetal HR becomes abnormal
Diagnosed with vaginal examination with speculum confirming diagnosis- cord may be palpable vaginally or visible beyond the level of the introitus (vaginal opening)
What is the management for a prolapsed umbilical cord?
Emergency C-Section recommended; instrumental vaginal may be possible if the cervix is fully dilates and the head is low
Cord should be kept warm and wet and have minimal handling as this causes vasospasm
the patient is asked to go on ‘all fours’ until preparations for an immediate caesarian section have been carried out
-Alternative position: left lateral position
Tocolytics to reduce uterine contractions
Retrofilling the bladder with 500-700ml of saline may be helpful as it gently elevates the presenting part
If treated early, fetal mortality in cord prolapse is low. Incidence has been reduced by the increase in caesarian sections being used in breech presentations.
What is shoulder dystocia?
When anterior shoulder of the baby becomes stuck behind the pubic symphysis of the pelvis after the head has been delivered
Obstetric emergency
Risk factors for shoulder dystocia?
Antenatal
- Macrosomia secondary to gestational diabetes
- High maternal BMI >30 and excessive weight gain in pregnancy
- Diabetes mellitus
- Post-term pregnancy
- Previous hx of shoulder dystocia
Intrapartum
- Prolonged labour - lack of progress in late 1st or 2nd stage labour
- Instrumental vaginal delivery (esp. rotational deliveries)
How does shoulder dystocia present?
- Usually the anterior shoulder is impacted against the symphysis pubis, often due to the failure of internal rotation of the shoulders
- Fetal deterioration is rapid, often without cord acidosis, largely due to cord compression and trauma.
What is the turtle neck sign?
Where the head is delivered but then retracts back into the vagina
What are the managment options of shoulder dystocia?
Get help (incl anaesthetics and paediatrics)
Episiotomy
McRoberts manoeuvre hyperflexion of the mother at the hip (bringing knees to abdomen) providing a posterior pelvic tilt lifting the pubic symphysis up and out of the way
Pressure to the anterior shoulder = pressing on the suprapubic region, putting pressure on the posterior aspect of the baby’s anterior shoulder to encourage it under pubic symphysis
Rubins manoeuvre = reaching into vagina, putting pressure on the posterior aspect of the baby’s anterior shoulder
Wood’s screw manoeuvre = performed during a Rubin’s manoeuvre - other hand is used to put pressure on the anterior aspect of the posterior shoulder - to rotate the baby, reverse motion can be tried
Zavanelli manoeuvre pushing the baby’s head back into the vagina so it can be delivered by emergency C-section
Pnemonic HELPERR
- H Call for help (including additional midwife, senior obstetrician, neonatologist, anaesthetist).
- E Episiotomy—remember shoulder dystocia is a bony problem, but an episiotomy may help with internal manoeuvres.
- L Legs into McRoberts’ (hyperflexed at hips with thighs abducted and externally rotated).
- P Suprapubic pressure applied to posterior aspect of anterior shoulder (must know which side fetal back is on) to dislodge it from under symphysis pubis; if continuous pressure fails, a rocking movement may be tried.
- E Enter pelvis for internal manoeuvres, which include:
- pressure exerted on the posterior aspect of anterior shoulder to adduct and rotate the shoulders to the larger oblique diameter (Rubin II)
- if this fails combine it with pressure on the anterior aspect of the posterior shoulder (Woods’ screw)
- if this fails, reversing manoeuvre may be tried with pressure on the anterior aspect of anterior shoulder and posterior aspect of posterior shoulder in opposite direction (reverse Woods’ screw).
- R Release of posterior arm by flexing elbow, getting hold of fetal hand, and sweeping fetal arm across chest and face to release posterior shoulder.
- R Roll over to ‘all fours’ may help aid delivery by the changes brought about in the pelvic dimensions (Gaskin manoeuvre).
