| Definition Labour: Cervical change accompanied by regular uterine contractions Abnormal Labour (Dystocia or arrest): Any deviation from the definition of normal labour "Show": As a result of the dilatation of the cervix, the operculum, which formed the cervical plug during pregnancy is lost. The women may see a blood stained mucoid discharge hours before, or within a few hour after labour starts. |
Overview Labour is the period from the onset of regular uterine contractions until expulsion of the placenta. Labour can be either:
Labour can be a "true" labour or a "false" labour. Braxton Hicks contractions are mild, often irregular contraction that may occur from 30weeks gestation and often confused as true labour. True labour is characterised by:
Labor is determined by assessing the cervical change versus time. Labour is initiated by the stretching of the cervix causing the release of oxytocin from the posterior pituitary gland
| Watch Video Physiology of Parturition (Hormones and Pregnancy) |
Stages of Labour - three stages
| Watch Video: Stage I of Labour |
The foetus ready for a normal labour
Mechanism of normal labour - Movement of baby through the pelvis during labour
| Side note Shoulder dystocia is a complication of labour and is where the anterior shoulder is stuck at the pubic symphysis (more discussed in the shoulder dystocia section) |
Monitoring during labour
| NORMAL LABOUR PARAMETERS | ||
| Nulliparatous | Multiparatous | |
| First Stage - Latent Phase | <20hr | <14hr |
| First Stage - Active Phase | >1.2cm/hr | >1.5cm/hr |
| Second Stage | <2hr (<3hr if epidural) | <1hr (<2hr if epidural) |
| Third Stage | <30min | <30min |
| Remember During 1st stage, 1-1.5cm cervical dilatation should take ~1hour for nulliparous women. This is quicker for multiparous women. |
| Remember During 2nd stage labour, birth should take place within 3hr for nulliparous women and within 2hr for multiparous women (on epidural) |
Labour can be either:
Induction of Labour As a general principle, induction of labour is undertaken when continuing a pregnancy is associated with greater level of maternal or foetal risk than delivery. 20% of all pregnancies are induced. The Bishops score helps assess the favourability for induction of labour.
| MODIFIED BISHOP'S SCORING SYSTEM (A total score >8 indicates a favourable cervix) | |||
| Cervix | SCORE | ||
| 0 | 1 | 2 | |
| Position | Posterior | Axial | Anterior |
| Length | 2cm | 1cm | <0.5cm |
| Consistency | Firm | Soft | Soft amd Stretchy |
| Dilatation | 0 | 1cm | >2cm |
| Station of the presenting part | -2 | -1 | 0 |
Indications for Labour Induction (IOL)
Methods of labour induction
When labour has progressed to full dilatation and concerns exist regarding wellbeing of the fetus, mother, or both, three options exist
Instrumental Vaginal Delivery Labour is divided into 3 stages. Stage 2 of labour (the stage from full cervical dilatation to the expulsion of the baby from the uterus) sometimes can be difficult and prolonged. Instrumental vaginal delivery helps with this stage and reduced need for caesarean section which is associated with more complications.
Indications for instrumental vaginal delivery
| Remember to discuss the need for instumental delivery, process and alternative options (caesarean section). Consent must be obtained |
Criteria for Intrumental vaginal delivery - FORCEPS
| Remember Postnatal care following instrumental vaginal birth requires attention to analgesia, voiding function, thromboembolic prophylaxis, rehabilitation of the pelvic floor, and counselling regarding the index birth and future births. |
Instruments used for Vaginal Delivery
| Side note Ventous appears safe for mother but forceps may be safer for baby |
Complications of instrumental vaginal delivery
Risk Factors for failed instrumental vaginal delivery
Overview Episiotomy is a surgically planed cut to enlarge the vaginal introitus so as to facilitate easy and safe delivery of the foetus.
| Definition Episiotomy: is a surgically planned incision on the perineum and the posterior vaginal wall during te second stage of labour Perineal tears: Laceration of the perineum are the result of overstretching or too rapid stretching of the tissues, especially if they are poorly extensile and rigid |
Consider episiotomy in the following circumstances:
| Remember Bulging thinned perineum during contraction just prior to crowning is the ideal time for performing a episiotomy |
Type of episiotomy
Complications of episiotomy
| Remember Episiotomy should be restricted to use in situations in which it is clearly indicated, and should not be routinely used during normal vaginal delivery |
Perineal tears
Repair of perineal tears
Overview Failure to progress also known as labour arrest, labour dystocia or abnormal labour is used to describe a labour pattern deviating from the observed (normal) in the majority of women who have a spontaneous vaginal delivery. About 20% of all labors ending in a live birth involve failure to progress.
Risk Factors
| Bandl's Ring An hourglass constriction ring of the uterus. Complication associated with obstructed labor in the second stage. The constriction forms between the upper contractile portion of the uterus and the lower uterine segment. |
| Remember Occipito-anterior position is the most common position (either left or right) |
Diagnosis
| NORMAL LABOUR PARAMETERS | ||
| Nulliparatous | Multiparatous | |
| First Stage - Latent Phase | <20hr | <14hr |
| First Stage - Active Phase | >1.2cm/hr | >1.5cm/hr |
| Second Stage | <2hr (<3hr if epidural) | <1hr (<2hr if epidural) |
| Third Stage | <30min | <30min |
Labour pattern deviating from the above normal labour parameters is considered abnormal labour or failure to progress. Other interventions are indicated such as instrumental delivery or most often caesarean section.
Overview Caesarian delivery is the surgical removal of the infant from the uterus through an incision made in the abdominal wall and an incision made in the uterus. Incidence is 15-30%. Caesarean sections can be done as a planned procedure (elective) or as an emergency.
| Definition Vaginal Delivery: Vaginal delivery is a natural process that usually does not require significant medical intervention Caesarean Delivery: Operation performed to deliver a viable fetus through an abdominal incision and is used as an alternative route to the natural vaginal birth Instrument Caesarean Delivery: |
Types of Caesarean Delivery
Indications
Anaesthesia
Intrapartum Complications
Postoperative Complications
Overview Occipitoposterior Position (OP) is the most common foetal malposition. Before labour, 15-20% of term foetuses in cephalic presentation are OP, but only 5% at vaginal delivery remain OP because most spontaneously rotate to Occipitoanterior position during labour.
| Remember The most common foetal position is left or right anteriorposterior position, cephalic presentation. |
Occipitoposterior Position (OP) and consequences on labour
| Risk Factors |
| Nulliparity |
| Maternal age >35 years |
| Obesity |
| Previous OP delivery |
| Decreased pelvic outlet capacity |
| Gestational age ≥ 41 weeks |
| Birth weight ≥ 4000g |
| Anterior placenta |
| Epidural anaesthesia |
Management OP position antepartum is not predictive of foetal position at delivery or adverse outcome, as 95% rotate to OA by delivery. Intrapartum management occur in second stage of labour and include:
| Remember Manual rotation in first stage has no benefits and may lead to cord prolapse |
| Side note Doctor can attempt manual rotate OP at 36 weeks or 37-38 weeks to a AP. |
Overview Breech presentation is normal in preterm pregnancy (<37 weeks gestation) and should not be considered abnormal, requiring intervention, until 37 weeks pregnancy is reached (at term). Breech presentation incidence of 40% at 20 wks gestation but incidence decreases with gestational
| Definition Breech Presentation: When the buttocks, foot or feet are presenting instead of the head in a longitudinal lie. |
Breech Classification:
| RISK FACTORS | |
| Maternal Factors | Foetal Factors |
| Polyhydramnios | Prematurity |
| Uterine anomalies e.g. bicornuate, septate | Foetal anomalies e.g. neurological, hydrocephalus, anencephaly |
| Space occupying lesions e.g. fibroids | Multiple pregnancy |
| Placental abnormalities e.g. placenta praevia | Foetal death |
| Contracted maternal pelvis | Short umbilical cord |
| Multiparity (esp grand multips) | |
Diagnosis
Management
| External Cephalic Version (ECV) procedure involves placing hands on mother’s abdomen (externally). The fetal bottom is then moved away from pelvis and fetus genty turned in several steps from breech, to a sideways position, and finally to a head-first position (cephalic) (~50% success rate and allows for vaginal delivery) |
| Remember Almost 90% foetuses presenting by the breech at term are delivered by caesarean section |
| Medical Causes | Condition |
| 6 H's | Hypovolaemia, Hypoxia, Hypoglycaemia, Hydrogen ions (acidosis), Hyper/Hypokalaemia, Hypothermia |
| 6 T's | Tension pneumothorax, Tamponade, Thrombosis (MI), Thromboembolism (PE), Trauma, Toxins |
| Obstetrics Causes | Condition |
| During Pregnancy | Ectopic pregnancy Antepartum Haemorrhage, Pre-Eclampsia/Eclampsia, Septic Shock |
| During Labour/Delivery | Amniotic Fluid Embolism (→ cardiorespiratory collapse), Inversion/rupture of uterus, Prolapsed cord, Shoulder dystocia, Acute foetal distress, Cardiac arrest |
| Post-Partum | Post-partum haemorrhage; Infection |
Major causes of Maternal mortality
Overview Uterine rupture occurs in 2 per 10,000 of all pregnancies. It is a rare but significant event. It may occur before or after birth and can vary in size.
| Defintion Uterine Rupture: disruption of the uterine muscle extending to and involving the uterine serosa or disruption of the uterine muscle with extension to the bladder or broad ligament Uterine dehiscence: disruption of the uterine muscle with intact uterine serosa |
Risk Factors
Signs and Symptoms
Management
| Remember After the emergency Document, Debrief and Disclosure |
Complications
Overview Uterine inversion occurs when the uterine fundus inverts within the endometrial cavity. 1 in every 2,500 births.
| Side note Uterine inversion can follow both vaginal and caesarean births and frequently occurs with the placenta still attached |
Stages of uterine inversion
Risk Factors
Signs and Symptoms
Management
| Remember do not attempt to remove the placenta (to prevent further haemorrhage) |
Complications
Overview Umbilical cord prolapse is a true obstetric emergency requiring immediate delivery. It is when the umbilical cord descends through the cervix alongside or past the presenting fetal part in the presence of ruptured membranes. If the cord is compressed, the foetus will die within 5-10 mins.
| Definition Cord Prolapse: The umbilical cord lies in front of or beside the presenting part in the presence of ruptured membranes. Cord Presentation: The presence of the umbilical cord between the presenting part and the cervix. |
Aetiology Mechanism of Foetal Death is from compression of the umbilical vessels by the presenting part and/or umbilical arterial vasospasm due to exposure of cord → acutely compromised foetal circulation→ foetal death or neurological sequelae unless immediate delivery.
Difference between Cord presentation and Cord prolapse In both conditions, a loop of the cord is below the presenting part. Difference is condition of membranes:
Incidence Cord Prolapse
Clinical Identification of Cord Prolapse
| RISK FACTORS FOR CORD PROLAPSE | |
| Pregnancy risk factors | Procedure-related |
| Placenta praevia | Obstetric manipulation increases risk →50% cases cord prolapse preceded by obstetric procedure |
| High / ill-fitting presenting part | Artificial Rupture of Membranes (ARM) especially if high-presenting part |
| High parity | Rotational instrumental delivery |
| Multiple pregnancy | Application of uterine pressure transducer |
| Prematurity | Vaginal manipulation of foetus with ruptured membranes |
| Polyhydramnois | |
| Malpresentations | |
| Long umbilical cord | |
| Remember Over 50% of cases of cord prolpase are preceded by an obstetric procedure |
Complications
Management
| Side note Excessive handling of the cord may cause it to spasm |
| Remember Paediatrician or neonatologist needs to be present. Remember paired cord blood samples of pH and base excess! |
| Remember After the emergency Document, Debrief and Disclosure |
Overview Shoulder dystocia is defined as a vaginal cephalic delivery that requires additional obstetric manoeuvres to deliver the foetus after the head has delivered and gentle traction has failed. Shoulder dystocia cannot be predicted nor prevented in the majority of cases. Brachial plexus injury (BPI) is one of the most important fetal complications of shoulder dystocia. Maternal morbidity is increased, particularly the incidence of postpartum haemorrhage as well as third and fourth-degree perineal tears
| Definition Shoulder Dystocia: Inability of the fetal shoulders to deliver spontaneously, usually due to the impaction of the anterior shoulder behind the maternal symphysis pubis. McRobert's Manoeuvre: The maternal thighs are sharply flexed against the maternal abdomen to straighten the sacrum relative to the lumbar spine and rotate the symphysis pubis anteriorly toward the maternal head. Suprapubic pressure: The operator’s hand is used to push on the suprapubic region in a downward or lateral direction in an effort to push the fetal shoulder into an oblique plane and from behind the symphysis pubis. Erb Palsy: A brachial plexus injury involving the C5-C6 nerve roots, which may result from the downward traction of the anterior shoulder; the baby usually has weakness of the deltoid and infraspinatus muscles as well as the flexor muscles of the forearm. The arm often hangs limply by the side and is internally rotated. |
| Risk Factors for Shoulder Dystocia |
| Maternal |
| Abnormal pelvic anatomy |
| Gestational diabetes |
| Post-dates pregnancy |
| Previous shoulder dystocia |
| Short stature |
| Fetal |
| Suspected Macrosomia |
| Labour related |
| Assisted vaginal delivery (forceps or vacuum) |
| Protracted active phase of first-stage labor |
| Protracted second-stage labor |
Management (HELPERR
| Remember The biggest risk factor for shoulder dystocia is fetal macrosomia, particularly in a woman who has gestational diabetes. |
Fetal Complications of Shoulder Dystocia
| Remember The most common injury to the neonate in a shoulder dystocia is brachial plexus injury, such as Erb palsy. |
Overview Amniotic fluid embolism is a rare and potentially catastrophic, but poorly understood condition that is unique to pregnancy. It may range from a relatively minor subclinical episode through to one which is rapidly fatal.
| Definition Amniotic Fluid: Amniotic Fluid Embolism: Venous Thrombo Embolism: |
Risk Factors - not really well understood could be an interplay of:
Clinical Presentation often occur in the intrapartum and immediate postpartum period
| Amniotic Fluid Embolism Triad: Hypotension, Fetal distress and pulmonary oedema/ARDS |
Diagnosis The diagnosis of AFE is a clinical one, based on the presence of cardiovascular and respiratory compromise and coagulopathy after the exclusion of other causes.
Management Supportive and advanced life suport
Overview Invasive implantation increases following caesarean section and is incrementally linked to the number of caesarean sections the woman has had.
| Definition Placenta accreta: Abnormal adherence of the placenta to the uterine wall due to an abnormality of the decidua basalis layer of the uterus. The placental villi are attached to the myometrium. Placenta increta: The abnormally implanted placenta penetrates into the myometrium. Placenta percreta: The abnormally implanted placenta penetrates entirely through the myometrium to the serosa. Often invasion into the bladder is noted. |
| Risk Factors |
| Placenta previa |
| Implantation over the lower uterine segment |
| Prior cesarean scar or other uterine scar |
| Uterine curettage |
| Fetal Down syndrome |
The usual management of placenta accreta (abnormal adherence of the placenta to the uterus) is hysterectomy.
Overview Postpartum Haemorrhage is potentialy life-threatening and is one of the leading causes of maternal death. The incidence of PPH may be underestimated by up to 50%, due to the clinical difficulty in accurately estimating blood loss
| Definition Postpartum Haemorrhage: a blood loss exceeding 500ml after delivery of the infant or any amout of blood loss postpartum that causes haemodynamic compromise in the women. Primary Postpartum Haemorrhage: occurs <24hours of delivery Secondary Postpartum Haemorrhage: occurs >24hours - 6weeks Antepartum Haemorrhage: Any bleeding from the genital tract after the 20 th week of pregnancy and before the onset of labour |
| RISK FACTORS | ||
| Maternal | Current Pregnancy | Labour |
| Previous PPH | Antepartum Haemorrhage | Long labour (>12hrs) |
| ↑Age | Multiple pregnancy | Syntocinon in labour |
| High parity | Macroscomia | Operative delivery |
| Coagulation disorders | Caesarean section | |
| Anaemia | ||
Causes of post partum haemorrhage
| Remember 4Ts for the causes of PPH: Tone, tissue, trauma, thrombin |
Maternal morbidity and mortaility from PPH is caused by:
Prevention
| Remember Significant haemorrhage can occur rapidly as maternal blood circulates through uterus at 500-800mL/min and 2/3 cases of PPH cannot be predicted. |
Management
Atony PPH Management Adminstration of medicine: promotes contraction of the uterine corpus - decreases the likelihood of uterine atony
| Remember the third stage of labor should be actively managed to reduce the risk of postpartum hemorrhage |
| Side note Consider uterine rupture as trauma. There can be signs of shock with not visible blood loss. There is abdominal tenderness, shoulder tip pain. |
| Definition Preterm Labour: Defined as delivery between 24 and 37 weeks Rupture of membranes (ROM): Leakage of amniotic fluid from the cervix Preterm Prelabour rupture of membrane (PPROM): Defined as rupture of membranes between 24 and 37 weeks in the absence of uterine activity (labour) Prelabour rupture of membrane (PROM): Defined as rupture of membranes in the absence of uterine activity (labour) after 37 weeks. NOT PRETERM |
Overview The diagnosis of preterm labour is generally based upon clinical criteria of regular, painful uterine contractions accompanied by cervical dilation and/or effacement between 24-27 weeks.
Investigations of preterm labour
Aetiology of Preterm labour
Prevention of preterm labour
Management of preterm labour
| Pharmacology Tocolytics. Contraindications: Antepartum haemorrhage, severe pulmonary Embolism, Maternal condition if pregnancy prolonged, heart disease and thyrotoxicosis (Salbutamol) |
Complication of Premature baby (as a result of preterm delivery)
Preterm prelabour rupture of membranes
| Chorioamnionitis |
Investigations
Prelabour rupture of membranes
