Week 3 Flashcards
Explain the classification of drugs in terms of teratogenicity.
- Category A, B1, B2, B3, C, D, X?
What is a Teratogen?
Give some examples.
Teratogen: an environmental factor that causes a permanent structural or functional abnormality, growth restriction, or death of the embryo or fetus.
- Effects depend on multiple factors.
- The pharmacological properties, dose, and regimen of drug exposure determine the risk of developing teratogenic birth defects.
- Stage of pregnancy in which exposure occurs.
- It’s important to note that the effects of teratogens on the fetus can be influenced by the timing of exposure. The first trimester (weeks 1 to 12) is the most vulnerable period for organ development, making the fetus more susceptible to teratogenic effects during this time.
List 8 Types of Teratogens.
Explain the effects of common teratogens on the fetus at different gestational ages - timeline?
- Alcohol
- Tobacco (Nicotine)
- Illicit Drugs (e.g., Cocaine, Heroin, Methamphetamine)
- Prescription Medications (e.g., Thalidomide, Isotretinoin, Valproic Acid)
- Infections (e.g., Rubella, Cytomegalovirus, Zika virus)
- Environmental Toxins (e.g., Lead, Mercury, PCBs)
- Radiation (e.g., X-rays, Ionizing radiation)
- Hyperthermia (High Body Temperature)
Teratogenicity - Maternal conditions
- Obesity? (7)
- Graves’ Disease? (6)
- Preterm birth
- Stillbirth
- Neural tube defects
- Congenital heart disease
- Cleft lip, cleft palate
- Limb reduction abnormalities
- Macrosomia
Teratogenicity - Maternal conditions
- Hypothyroidism?
- Phenylketonuria?
Hypothyroidism
1. Congenital hypothyroidism
2. Congenital iodine deficiency syndrome
Teratogenicity - Alcohol: fetal alcohol syndrome (embryo-fetal alcohol syndrome)
- Epidemiology?
- Mechanism of Teratogenicity?
- Clinical Features - 7 Dysmorphic features?
Alcohol: fetal alcohol syndrome
- Epidemiology: Most common cause of teratogenic damage in children (0.2–1.5 per 1,000 live births), Most common preventable cause of intellectual disability in the US
- Mechanism of teratogenesis: Failed neuronal and glial cell migration
Teratogenesis - Cigarette smoking during pregnancy
- Mechanism of teratogenesis?
- 6 Effects?
Cigarette smoking during pregnancy - Mechanism of teratogenesis
Nicotine: ↑ catecholamine release → vasoconstriction of uteroplacental blood vessels → compromised blood flow and oxygen delivery to the fetus
Carbon monoxide: ↑ COHb causes tissue hypoxia
Teratogenicity - Cocaine & Opioids
- Mechanism of teratogenesis of cocaine?
- 4 Effects of cocaine on the fetus?
- Mechanism of teratogenesis of opioids?
- 6 Effects of cocaine on the fetus?
Cocaine Use in Pregnancy
- Mechanism of teratogenesis: cocaine → vasoconstriction of the uteroplacental placental vessels→ compromised blood flow and oxygen delivery to the fetus
- Effects
1. Intrauterine growth retardation
2. Low birth weight
3. Preterm labor
4. Placental abruption
What are TORCH infections?
Describe the Barker hypothesis in relation to the implications for health care provision and planning.
- 4 Key points?
- 6 implications?
The Barker hypothesis, also known as the Developmental Origins of Health and Disease (DOHaD) hypothesis, is a concept proposed by epidemiologist David Barker in the late 1980s. The hypothesis suggests that the environment and nutrition experienced during fetal development and early life can have long-term effects on an individual’s health and disease risk later in life.
Cesarean section
- 2 Advantages?
- 2 Disadvantages?
- 4 Maternal indications for a Primary cesarean delivery?
- Maternal indications for Secondary cesarean delivery?
- 3 Indications for Emergency cesarean delivery?
Advantages
1. Safest method of birth if maternal and/or fetal health is compromised by a vaginal delivery
2. Fetal birth trauma is rare.
Disadvantages
1. Postoperative complications
2. Long recovery period
Fetal indications for Caesarean section
- Primary caesarean delivery? (4)
- Emergency caesarean delivery? (3)
Fetal indications for Caesarean section
Primary caesarean delivery
1. Fetal growth retardation with circulatory depression
2. Premature birth, if further risk factors are present, e.g., infection
3. Fetal malformations that hinder a natural birth (e.g., severe hydrocephalus)
4. Multiple pregnancy with a significant difference in fetal weight
Emergency caesarean delivery
1. Immediate threat to life of fetus
2. Pathological CTG (particularly persistent, severe fetal bradycardia)
3. Fetal acidosis
List 8 Indications for C-Section?
Possible Complications of Cesarean Section
- 10 Maternal?
- 2 Fetal?
Risks for your baby
The most common problem affecting babies born by caesarean section is temporary breathing difficulty. There is also a small risk of your baby being cut during the operation. This is usually a small cut that isn’t deep. This happens in 1 to 2 out of every 100 babies
delivered by caesarean section, but usually heals without any further harm.
5 Benefits of a C-Section?
6 Complications of a C-Section?
What are the 2 options for Mode of delivery after cesarean delivery?
TOLAC: A planned or attempted childbirth in a mother who has had a prior cesarean delivery. Results in vaginal birth after cesarean (VBAC) if successful or a repeat cesarean delivery if unsuccessful. Associated with increased risk of rupture of the cesarean scar on the uterus. Contraindicated in patients with a history of > 2 prior low-transverse cesarean deliveries and classic cesarean delivery.
List 2 Indications for a TOLAC?
3 Indications for Planned repeat cesarean birth?
Describe the issues around vaginal birth after caesarean section (VBAC).
What are 4 Factors Increasing success in VBAC and 9 Factors reducing success in VBAC?
- Previous vaginal birth, especially successful VBAC, is the strongest predictor of success, with VBAC rates of 87-91% reported in that group.
- Induced labour, no previous vaginal birth, a BMI greater than 30 Kg/m2, and previous Caesarean section for dystocia are factors that all reduce the success rate; Landon reported if all four are present then the success rate was only 40%.
4 Benefits of a successful VBAC?
7 Risks of VBAC?
5 Benefits and 3 risks of elective repeat Caesarean section at 39 weeks?
What is the definition of Operative Vaginal Delivery?
- Can we avoid operative vaginal delivery? (7)
Operative Vaginal Delivery = Delivery of the fetus by Forceps or Vacuum extractor.
Avoiding an Operative Vaginal Delivery
1. Continuous support in labour
2. Correct posture in labour
3. Mobilisation in labour
4. Avoidance of epidural
5. Avoidance of epidural in early labour
6. Delayed pushing when epidural used
7. Judicious use of oxytocin in 2nd stage
How are operative vaginal deliveries classified?
Classification of operative vaginal delivery
Extraction is classified by the status of the fetal head at the time of vacuum application and the degree of rotation necessary. The lower the classification, the less the risk of complications.
Indications for operative vaginal delivery?
5 Prerequisites of operative vaginal delivery?
Certain fetal conditions such as fetal bleeding disorders (e.g., hemophilia, neonatal alloimmune thrombocytopenia, Von Willebrand’s disease), fetal demineralizing diseases (e.g., osteogenesis imperfecta) preclude the use of a vacuum to expedite delivery. Its use is discouraged at less than 34 weeks estimated gestational age. Prior to its use, the obstetrician should ensure that all of the above prerequisites have been met and the patient agrees to the care plan.
Obstetric forceps delivery
- Definition?
- 4 Types?
- 4 Classifications?
Obstetric forceps delivery
- 4 Indications?
- 7 Prerequisites?
- 4 Advantages over vacuum delivery?
- 4 Maternal complications?
- 5 Fetal complications?
Obstetric forceps delivery
Advantages (compared to vacuum delivery)
1. Scalp injuries are less common
2. Cannot undergo decompression and “pop off”
3. Fewer neonatal injuries (cephalohematoma, retinal hemorrhage, and transient lateral rectus palsy)
4. Higher rate of successful delivery vaginally
Complications
- Maternal: obstetric lacerations (cervix, vagina, uterus), perineal hematomas, urinary tract injury, anal sphincter injury
- Fetal: head or soft tissue trauma (e.g., scalp lacerations, injured ears), facial nerve palsy, intracranial hemorrhage, retinal hemorrhage, skull fractures, fetal death (rare)
Vacuum extractor delivery
- Definition?
- 3 Indications?
- 3 Advantages (compared to forceps delivery)?
Vacuum extractor delivery
Definition: a vacuum extractor is a metal or plastic cup, attached to the fetal head with a suction device, that enables traction of the fetal head during vaginal delivery
Indications
1. Prolonged second stage of labor
2. Nonreassuring fetal heart rate
3. To avoid/assist maternal pushing efforts
Advantages (compared to forceps delivery)
1. Requires minimum space
2. ↓ incidence of third- and fourth-degree perineal tears
3. Less knowledge about exact position and attitude of the fetal head is acceptable
Vacuum extractor delivery
- 8 Prerequisites?
- Complications - 1 maternal? 3 fetal?
Vacuum extractor delivery - Complications
- Maternal: suction of maternal soft tissue → hematomas or lacerations
- Fetal: cephalohematoma , scalp lacerations, life-threatening head injury (e.g., intracranial hemorrhage or subgaleal hematoma)
- A routine episiotomy is not recommended with assisted vaginal delivery because of the risk of poor healing and anal sphincter injury!
What is a Ventouse? Where should it be placed?
Ventouse deliveries are associated with:
1. Lower success rate
2. Less maternal perineal injuries
3. Less pain
4. More cephalhaematoma
5. More subgaleal haematoma
6. More fetal retinal haemorrhage
Indications for Performing an Assisted Vaginal Delivery
- 3 Maternal?
- 2 Fetal?
- 4 Causes of Failure of instrumental delivery?
- When should operative vaginal delivery be abandoned? (3)
- Contraindications for Performing an Assisted Vaginal Delivery - 6 Absolute? 3 Relative?
When should operative vaginal delivery be abandoned?
1. When criteria not met
2. Failure of progressive descent with moderate traction during each contraction
3. Delivery not imminent after 3 pulls
8 Pre-requisites for performing an instrumental delivery?
Where should it be performed?
Pre-requisites for performing an instrumental delivery are:
1. Fully dilated.
2. Ruptured membranes
3. Cephalic presentation
4. Defined fetal position.
5. Fetal head at least at the level of the ischial spines, and no more than 1/5 palpable per abdomen
6. Empty bladder
7. Adequate pain relief
8. Adequate maternal pelvis
7 Complications of Operative Vaginal Delivery?
- Failed instrumental delivery
- Caesarean section in 2nd stage
- Post partum haemorrhage-atonic and traumatic, or both
- Genital tract trauma – especially 3rd and 4th degree perineal tears
- Pelvic floor injury- bladder and bowel
- Long term- bladder and bowel dysfunction
- Fetal injuries- Laceration, cephal haematoma, fracture
What needs to be involved in the aftercare of a woman who has had an operative vaginal delivery? (6)
- Debrief
- Analgesia
- Bladder care
- Perineal care
- Pelvic floor physiotherapy
- Advice regarding future deliveries
2 Types of caesarean section?
4 Indications for a Classical caesarean section?
Lower segment caesarean section
- Standard practise to make an incision in lower uterine segment after reflecting cervico- vesical peritoneum
- Lower uterine segment heals better than upper uterine segment incision
- Blood loss is less compared to upper uterine incision
- Vaginal birth after 1 previous lower segment CS is possible if no contraindication; Scar dehiscence in labour at VBAC is 0.5%
Classical caesarean section - Very rare. Incision in upper uterine segment
Indications:
1. Placanta praevia/Accreta
2. Fibroids in lower uterine segment
3. Dense bladder adhesions to lower uterine segment
4. Extreme prematurity where lower uterine segment is not formed
**Complications of Caesarean section **
- 6 Immediate?
- 2 Intermediate?
- 6 Late?
- 6 Post caesarean section advice points?
Post caesarean section advice
1. Mobilisation
2. Hydration
3. Analgesia
4. Wound care
5. Contraceptive advice
6. Spacing of pregnancy- 18-24 months between births
What are the different categories for emergency c-section?
The Royal College of Obstetricians and Gynaecologists (RCOG) recommends that when a Category 1 section is called, the baby should be born within 30 minutes (although some units would expect 20 minutes). For Category 2 sections, there is not a universally accepted time, but usual audit standards are between 60-75 minutes.
Describe the pattern of fetal growth throughout the 40 weeks of gestation.
List 12 factors that affect the growth velocity of the fetus, particularly in the last trimester.
Define:
- Small for gestational age (SGA)?
- Fetal growth restriction (FGR)?
- Low birth weight?
Describe the Aetiology and Pathophysiology of Small Gestational Age?
- Small for gestational age (SGA) – an infant with a birth weight <10th centile for its gestational age.
- Severe SGA – a birth weight < 3rd centile.
- Fetal SGA – an estimated fetal weight (EFW), or abdominal circumference (AC) <10th centile.
- Severe fetal SGA – an EFW or AC <3rd centile.
- Fetal growth restriction (FGR) – when a pathological process has restricted genetic growth potential. This can present with features of fetal compromise including reduced liquor volume (LV) or abnormal doppler studies. The likelihood of FGR is higher in a severe SGA fetus.
- Low birth weight refers – an infant with a birth weight <2500g.
Diagnosis and Clinical features of Small for Gestational Age?
4 Other Investigations?
Risk factors for a Fetus that is Small for Gestational Age
- 8 Minor?
- 10 Major?
Other investigations that may be appropriate include:
1. Detailed fetal anatomical survey
2. Uterine artery Doppler (UAD)
3. Karyotyping
4. Screening for infections including congenital cytomegalovirus, toxoplasmosis, syphilis and malaria
Management of Small for Gestational Age
- Prevention?
- Surveillance?
- Delivery?
Prevention
- Modifiable risk factors should be managed to help prevent SGA, including promoting smoking cessation and optimising maternal disease.
- Women at high risk for pre-eclampsia should be started on 75mg of aspirin 16 weeks gestation until delivery.
Surveillance
- UAD should be the primary surveillance tool in the SGA fetus. If it is normal repeat every 14 days. If it is abnormal repeat more frequently or consider delivery.
- Other tests useful in surveillance include symphysis fundal height (SFH), middle cerebral artery (MCA) Doppler, ductus venosus (DV) Doppler, cardiotocography (CTG) and amniotic fluid volume.
Delivery
- If delivery is being considered between 24 and 35+6 weeks gestation a single course of antenatal steroids should be given.
What are the complications of a fetus that is small for gestational age?
- 9 Neonatal complications?
- 9 long-term complications
Complications of SGA
The use of these customised centile charts has been shown to reduce neonatal morbidity and mortality. Increased morbidity and mortality are most closely associated with FGR. Antenatally, there is an increased risk of stillbirth. Potential neonatal and long-term complications are demonstrated in the table below.
Outline the normal mechanics of labour.
- What are the 7 cardinal movements of labour? (EDFIERE)
Mechanism of labor
The mechanisms of labor, also known as the cardinal movements, involve changes in the position of the fetus’s head during its passage in labor. These are described in relation to a vertex presentation. Although labor and delivery occurs in a continuous fashion, the cardinal movements are described as the following 7 discrete sequences:
1. Engagement
2. Descent
3. Flexion
4. Internal rotation
5. Extension
6. Restitution and external rotation
7. Expulsion
Outline the physiology of labour.
Describe 9 signs and symptoms of labour and explain the underlying mechanism.
Labor is the process by which the uterus contracts to expel the fetus from the womb. It is a complex physiological event marked by distinct stages and accompanied by various signs and symptoms. The onset of labor is triggered by a combination of hormonal changes and the maturation of the fetus.
Describe the concept of “the active management of labour”.
- Purpose?
- 3 components?
Active management of the third stage of labour involves giving a prophylactic uterotonic, early cord clamping and controlled cord traction to deliver the placenta. With expectant management, signs of placental separation are awaited and the placenta is delivered spontaneously. Active management was introduced to try to reduce haemorrhage, a major contributor to maternal mortality in low‐income countries.
Active management of third stage definition includes:
1. Routine use of uterotonic (oxytocic) medications.
2. Controlled cord traction (CCT) after signs of separation of the placenta
3. Delayed clamping and cutting of the cord.
Outline the procedural steps of active management of labour.
List 7 Indications for Induction of Labour?
- Post-term pregnancy (≥ 42 weeks of pregnancy or gestation)
- PPROM after 34 weeks
- PROM at term
- Hypertension during pregnancy, preeclampsia, eclampsia, HELLP syndrome
- Maternal diabetes to avoid post-term pregnancy (risk of macrosomia)
- Maternal request at term
- Intrauterine fetal demise
Induction of labour is indicated when it is thought that delivering the baby will be safer for the baby and/or the mother, than for the baby to remain in utero. Note: In the UK, NICE guidelines (2008) state that induction of labour should NOT be offered on maternal request alone.
Contraindications for Induction of Labour.
- 7 Absolute?
- 4 Relative?
- History of uterine rupture; previous classical cesarean section
- Complete placenta previa
- Vasa previa
- Transverse fetal lie
- Cord prolapse
- Active maternal genital herpes
- Nonreassuring fetal heart rate
What are the 3 Main methods of Induction of Labour?
There are three main methods of induction – vaginal prostaglandins, amniotomy and membrane sweep. There is a lack of evidence regarding other methods of IOL, including homeopathy, acupuncture and sexual intercourse.
List 7 Complications of Induction of Labour>
- Failure of induction (15%) – offer a further cycle of prostaglandins, or a caesarean section.
- Uterine hyperstimulation (1-5%) – contractions last too long or are too frequent, leading to fetal distress. Can be managed with tocolytic agents (anti-contraction) such as terbutaline.
- Cord prolapse – can occur at time of amniotomy, particularly if the presentation of the fetal head is high.
- Infection – risk is reduced by using pessary vs tablet/gel, as fewer vaginal examinations are required to check progress.
- Pain – IOL is often more painful than spontaneous labour. Often epidural analgesia is required.
- Increased rate of further intervention vs spontaneous labour – 22% require emergency caesarean sections, and 15% require instrumental deliveries.
- Uterine rupture (rare)
Outline the normal mechanics of labour.
- What are the 7 cardinal movements of labour? (EDFIERE)
Mechanism of labor
The mechanisms of labor, also known as the cardinal movements, involve changes in the position of the fetus’s head during its passage in labor. These are described in relation to a vertex presentation. Although labor and delivery occurs in a continuous fashion, the cardinal movements are described as the following 7 discrete sequences:
1. Engagement
2. Descent
3. Flexion
4. Internal rotation
5. Extension
6. Restitution and external rotation
7. Expulsion
Describe the basic mechanisms of pain in labour (8).
List the Non-pharmacological strategies and Pharmacological options for pain relief during labour?
Outline the Non-pharmacological options for pain during labour?
Pain Management during labour - TENS therapy
- Benefits?
- Cautions?
- Application and use?
Amniotic Fluid Embolism
- Definition?
- Pathophysiology?
A rare life-threatening condition caused by the entry of fetal cells and debris (from amniotic fluid) into maternal circulation.
- - Amniotic fluid embolism (AFE) is a recognised, yet rare cause of maternal collapse. It is often a fatal complication of pregnancy and the puerperium, and is a direct cause of maternal death.
- The most up to date UK data states that there is an incidence of 2/100,000 pregnancies.
- The cause of this phenomenon is still under debate however possible roles have been attributed to strong uterine contractions, excessive amniotic fluid and disruption of vessels supplying the uterus.
- It therefore remains a condition that is neither predictable nor preventable, with no established accurate premortem diagnostic test or investigation.
Amniotic Fluid Embolism - Risk Factors? (7)
- Maternal age > 30 years
- Multiparity
- Complicated labor (e.g., placenta previa/abruption, forceps delivery, cesarean delivery, eclampsia)
- Invasive procedures (e.g., amniocentesis, abortion)
- Blunt abdominal trauma
Amniotic Fluid Embolism
- 8 Clinical features?
The physiology related to amniotic fluid embolism has been described as similar to anaphylaxis or severe sepsis. As such, the manifestations of this complication of pregnancy resemble these disease processes. It is characterised as an acute condition with the sudden onset of:
1. Hypoxia/respiratory arrest
2. Hypotension
3. Fetal distress
4. Seizures
5. Shock
6. Confusion
7. Cardiac arrest
8. Disseminated intravascular coagulation (this may be the first sign in some cases however nearly all patients will go on to develop this within 4 hours)
Amniotic Fluid Embolism
- Investigations & Diagnostics? (4)
General principles
- AFE is a clinical diagnosis based on the sudden onset of typical peripartum clinical features.
- Supportive studies are used to help guide management and rule out complications.
- If AFE is suspected clinically, do not delay treatment to obtain diagnostic studies.
Laboratory studies
1. Arterial blood gas analysis: hypoxemia, acid-base disorders
2. CBC: anemia, thrombocytopenia
3. Coagulation studies: ↑ aPTT, ↑ PT, ↓ fibrinogen
4. Pulmonary artery blood sample: presence of squamous cells, hair, or other fetal debris in maternal blood
Amniotic Fluid Embolism - Management?
Umbilical Cord Prolapse
- 3 Types?
Umbilical cord prolapse - 3 Types:
1. Overt umbilical cord prolapse
2. Occult umbilical cord prolapse
3. Cord presentation
Umbilical Cord Prolapse
- 5 Risk Factors? What are the pre-disposing factors for cord prolapse?
- Pathophysiology?
Pathophysiology
Umbilical cord prolapse is where the umbilical cord descends through the cervix, with (or before) the presenting part of the fetus. Subsequently, fetal hypoxia occurs via two main mechanisms:
1. Occlusion – the presenting part of the fetus presses onto the umbilical cord, occluding blood flow to the fetus.
2. Arterial vasospasm – the exposure of the umbilical cord to the cold atmosphere results in umbilical arterial vasospasm, reducing blood flow to the fetus.
Overt umbilical cord prolapse
- Definition?
- Epidemiology?
- Aetiology?
- Clinical features?
- Diagnostics?
- Management?
Overt umbilical cord prolapse
The umbilical cord lies between the presenting part of the fetus and the maternal pelvic wall. The membranes are ruptured, and the cord prolapses into the cervical canal or further. There is a high risk of cord compression and life-threatening hypoxia for the fetus. Management includes intrauterine resuscitation measures and emergency cesarean delivery.
Cord Presentation
- Definition?
- Aetiology?
- Clinical features?
- Diagnostics?
- Treatment?
The umbilical cord lies between the fetal presenting part and the pelvic wall with the membranes intact. Cord compression and restriction of blood flow to the fetus may occur. Placing the mother in a different position (e.g., Trendelenburg) may result in spontaneous reduction of the cord into the uterus.
Umbilical Cord Prolapse
- Clinical features & Differential Diagnosis?
- Management - A midwife tells you that she has just done a vaginal examination on a patient in labour and could feel the umbilical cord. What do you do?
- Summary?
- Umbilical cord prolapse occurs when the cord descends through the cervix and is alongside or below the presenting part of the fetus.
- It is an obstetric emergency, with a fetal mortality rate of 91 per 1000.
- The diagnosis should be suspected in any patient with a non-reassuring fetal heart trace and absent membranes.
- The first step is to call for help when the diagnosis is made.
- Manage by manually elevating the presenting part, and deliver via the quickest mode (usually Caesarean section).
Shoulder dystocia
- Definition?
- Epidemiology?
- 5 Risk Factors?
- Clinical Features? Turtle Sign?
- Diagnosis?
Shoulder Dystocia
- Definition: an obstetric emergency in which the anterior shoulder of the fetus becomes impacted behind the maternal pubic symphysis during vaginal delivery
- Epidemiology: ∼ 0.2–3% of births
- Risk factors
1. History of shoulder dystocia
2. Fetal macrosomia
3. Prolonged second stage of labor
4. Maternal diabetes mellitus
5. Maternal obesity
Shoulder Dystocia
- 5 Pre-labour risk factors?
- 5 Intrapartum risk factors?
- Pathophysiology?
Pathophysiology of Shoulder Dystocia
- In normal labour, the fetal head is delivered via extension out of the pelvic outlet. This is followed by restitution of the fetal head, so it lies in a neutral position in relation to its spine. This means the fetal shoulders now lie in an anterior-posterior position.
- Shoulder dystocia occurs when there is impaction of the anterior fetal shoulder behind the maternal pubic symphysis, or impaction of the posterior shoulder on the sacral promontory. A delay in delivery of the fetal shoulders leads to hypoxia in the fetus, proportional to the time delay to complete delivery.
- Applying traction on the fetal head can result in fetal brachial plexus injury, and is major cause for litigation in obstetrics.
Shoulder Dystocia
- Management?
- 2 First Line Manoeuvres?
- 2 Second Line (‘Internal’) Manoeuvres?
- 3 Rare Further Manoeuvres?
Management
REMEMBER – If managed appropriately the risk of permanent brachial plexus injury can be almost eliminated. The immediate steps in the management of shoulder dystocia include:
1. Call for help – shoulder dystocia is an obstetric emergency (will need senior obstetrician, senior midwife and paediatrician in attendance).
2. Advise the mother to stop pushing – this can worsen the impaction.
3. Avoid downwards traction on the fetal head (increases risk of brachial plexus injury) – only use “routine” axial traction (i.e. keep the head in line with the baby’s spine), and do not apply fundal pressure (increases the risk of uterine rupture).
4. Consider episiotomy – this will not relieve obstruction but can make access for manoeuvres easier.
Outline the manoeuvres used to attempt to treat a Shoulder Dystocia?
Shoulder Dystocia
- 2 Maternal complications?
- 3 Fetal complications?
- Prognosis?
Complications
The complications of shoulder dystocia can be divided into maternal and fetal:
Maternal
1. 3rd or 4th degree tears (3-4%)
2. post-partum haemorrhage (11%).
Fetal
1. Humerus or clavicle fracture
2. Brachial plexus injury (2-16%)
3. Hypoxic brain injury
At her routine antenatal visit at 36 weeks gestation, a 36 year old woman in her third pregnancy has a fetus with a high ‘floating’ fetal head. How would you manage the remainder of the pregnancy? Would your management be different if this was her first baby?
A “high floating” fetal head at 36 weeks gestation refers to a situation where the baby’s head is not yet engaged in the pelvis (station and is positioned higher up in the abdomen. This condition is also known as “unengaged” or “floating” head. Traditionally “engagement of fetal head is said to take place usually by 36 weeks of gestation and should remain well engaged from that date onwards”. Engagement has been defined as passage of biparietal diameter of fetal skull through the plane of the pelvic inlet. The sign of a high head at term in primigravidae is not a welcome finding and calls for investigation as to possible causes , certainly many obstetricians take a pessimistic attitude towards eventual vaginal delivery, if the foetal head is not engaged at the onset of labour. At term, the options for management of breech presentation are (i) external cephalic version; (ii) Caesarean section; or iii) vaginal breech birth.
A 24 year old woman in her second pregnancy has a fetus with a breech presentation at 36 weeks gestation. Discuss the subsequent management options both now and if the presentation is still breech at term.
2) Caesarean Section
- If the external cephalic version is unsuccessful, contraindicated, or declined by the woman, current UK guidelines advise an elective Caesarean delivery.
- This is based on evidence that perinatal morbidity and mortality is higher in cases of planned vaginal breech birth (compared to Caesarean) in term babies. There is no significant difference in maternal outcomes between the two groups.
- The evidence for preterm babies is less clear, but generally C/S is preferred due to the increased head to abdominal circumference ratio in preterm babies.
What is a posterior occiput?
Fetal Position
Occiput posterior position: Fetal occiput points towards the maternal sacral promontory with face to pubis symphysis; the fetus faces upward. The occiput faces the promontory. From the obstetrician’s perspective with the mother in the supine position, the child faces the ceiling during birth.
Discuss the diagnosis and management of the posterior position of the occiput in labour (consider both the first and second stages).
The posterior position of the occiput, also known as occiput posterior (OP) or “sunny-side up” presentation, refers to a fetal position where the back of the baby’s head is facing the mother’s spine during labor. This positioning can sometimes lead to a more challenging labor and delivery due to factors such as increased back pain and slower progression.
Diagnosis:
1. Digital Examination: During a vaginal examination, the healthcare provider can feel the baby’s position and determine if the occiput is facing the mother’s spine.
2. Fetal Heart Rate Monitoring: The pattern of the baby’s heart rate can give clues about their position. In a posterior position, the baby’s back may be closer to the mother’s back, making it more challenging to pick up the heart rate.
What may cause delay in the latent phase of labour? (13)
What may cause delay in the active phase of labour?
Slow progress in labour may be more likely if your:
1. the baby is large
2. the baby has a large head
3. the baby is in a difficult position
4. contractions aren’t strong enough and your cervix doesn’t open (dilate)
5. pelvis is too small to fit your baby through
You may also have a greater chance of slow progress in labour if:
1. you are overweight
2. you have gained a lot of weight during your pregnancy
3. this is your first baby
A prolonged latent phase can cause a prolonged active phase if the mother/fetus have exhausted energy levels.
Delay in latent phase - Management?
Commence a Partogram
Delay in ACTIVE phase - Management
- Diagnosis?
- All women?
- Nulliparous?
- Multiparous?
Commence a Partogram
Why is oxytocin sometimes used in spontaneous labour (i.e. where it is not needed for induction of labour)?
Oxytocin is a hormone that plays a crucial role in various reproductive processes, including uterine contractions during labor and the milk ejection reflex during breastfeeding. While oxytocin is commonly associated with inducing labor, it is also used in spontaneous labor (labor that starts on its own without the need for induction) for specific medical reasons to enhance or augment the progress of labor. This approach is known as “oxytocin augmentation” or “oxytocin augmentation of labor.”
Indications for Augmentation of labour with IV Oxytocin
1. > Slow progress in active first stage (<1cm over 2 hours from 5 cm dilatation)
2. > Minimal descent of presenting part (<1 cm) in second stage after 60-90 minutes of active
pushing with contractions less than 3/10 minutes
The progress of labour is noted to be slow in a primigravida. A syntocinon infusion is commenced. After one hour of strong contractions the fetal heart rate is noted to be 110 beats per minute for several minutes (previously, the heart rate was 140/minute). The uterine resting tone is high. What is the possible cause of this? What steps should be taken?
Uterine hypercontractility without signs of fetal compromise (hypertonus /
tachysystole)
1. Reduce oxytocin infusion rate and seek medical review
2. Maternal reposition
3. Increase intravenous fluids
4. Consider tocolysis
Uterine hypercontractility with signs of fetal compromise (hyperstimulation)
1. Reduce or discontinue oxytocin infusion
2. Position woman on her left side
3. Increase intravenous fluids
4. Review by medical officer
5. Palpate the uterus to determine uterine response to management
6. Consider need for uterine tocolytic
A pregnant young woman tells you that she jogs 1 or 2 km each day - she asks about the safety of this. What do you tell her?
Types of activity - Include both aerobic and muscle strengthening exercises in your daily routine, which could include:
- brisk walking, stationary cycling, swimming, dancing, light resistance activities.
- You should aim to do pelvic floor exercises every day, while pregnant, then for life, to keep your pelvic muscles strong and avoid problems like incontinence. Learn the correct technique for pelvic floor exercises.
8 Medical conditions to avoid exercise with in pregnancy?
Sport and activity to avoid in pregnancy?
You should avoid exercise in pregnancy if you have the following medical condtions:
1. your waters have broken (ruptured membranes)
2. uncontrolled high blood pressure
3. pulmonary or venous thrombus
4. low lying placenta (placenta praevia) in late pregnancy
5. intra-uterine growth retardation
6. incompetent cervix
7. uterine bleeding
8. pre-eclampsia.
List 13 screening tests which should be routinely offered at the start of a normal pregnancy, and explain why?
We screen for:
1. Blood group
2. Haematological conditions
3. Infections
4. Chromosomal abnormalities
5. Medical conditions
Outline the Antenatal care timeline and what should be performed at each visit?
- 1st Visit; Booking bloods
- 16
- 18-20: anatomy scan
- 24
- 28
- 32, 34, 36, 38, 40, 41
Outline which tests should be performed at booking?
Outline the timeline for pregnancy scan dates?
What needs to be performed at every antenatal visit? (10)
How can you assess alcohol use during pregnancy - level of risk?
Which questions to ask regarding history taking of previous births?
Outline who needs Haemoglobinopathy screening?
Describe the non-invasive screening tests for genetic abnormalities in the first trimester and describe the definitive tests to confirm diagnosis in the high-risk group.
- Should screening tests to determine fetal abnormalities be done in all pregnancies?
- What tests are available in the first trimester for aneuploidy screening?
- Discuss the diagnostic tests if the first trimester screening shows a high-risk result.
- All pregnant women (regardless of age) should be offered noninvasive aneuploidy screening tests (before 20 weeks of gestation)
Possible tests
1. Testing maternal serum: measurement of specific biomarkers and ultrasound markers that indicate an increased risk for aneuploidy
2. Cell-free fetal DNA testing - All pregnant women (regardless of age) should be given the alternative option to undergo invasive genetic testing (amniocentesis or chorionic villus sampling)
- Pre-test counseling must be provided: inform the parents that screening is voluntary; explain the difference between screening and diagnostic tests, risk of false positive and false negative tests, explain option of terminating the pregnancy if aneuploidy is diagnosed
What is a Nuchal translucency scan?
- Purpose?
- When is it performed?
- What do the results mean?
- Cost?
- Measures the subcutaneous area between the skin and cervical spine of the fetus in the sagittal section. Nuchal translucency increases when fluid accumulates in the area. A nuchal translucency scan is an ultrasound scan that measures your baby’s nuchal translucency — a fluid-filled space behind your baby’s neck. This measurement can help your doctor estimate the risk of your baby having a chromosomal abnormality such as Down syndrome.
- A nuchal translucency scan is done between 11 and 14 weeks of pregnancy. If your doctor has referred you for a dating scan, it can often happen at the same time.
- Medicare covered.
What is Non-invasive prenatal testing (NIPT)/Cell-free fetal DNA testing?
- What is it?
- What does it test for?
- Cost?
- When?
- The non-invasive prenatal test (NIPT) is a very accurate screening test.
- The NIPT involves a simple blood test that is done in your first trimester of pregnancy.
- During pregnancy, some of the baby’s DNA passes into your bloodstream. The non-invasive prenatal test analyses the genetic information contained in this DNA. It’s used to screen for a number of genetic conditions. The test is particularly sensitive to Down syndrome.
- In Australia, NIPTs are offered in private centres and involve an out-of-pocket cost. They are sometimes referred to by different names, depending on the company that makes them. They might be called: Harmony, Generation or Percept. Cost ~$400 to $500 for an NIPT. Not covered by PHI.
- An NIPT is done from 10 weeks into the pregnancy.
First-trimester combined screening
- Timing?
- Description?
- Evaluation?
First-trimester combined screening
Timing: 10–13 weeks gestation
Description:
- Sonographic nuchal translucency (NT)
- β-HCG (human chorionic gonadotropin) in maternal serum
- PAPP-A (pregnancy-associated protein A) in maternal serum
Evaluation:
- Risk of aneuploidy is evaluated based on maternal age, lab results, and ultrasound. If abnormal, provide counseling and perform chorionic villus sampling (CVS) or amniocentesis
How can we check on the health of a fetus? Remember to consider clinical methods as well as tests. Which of these methods, if any, should be used in a normal pregnancy?
- 5 Clinical methods?
- 5 Diagnostic tests?
6 Maternal screening blood tests in pregnancy?
- Group and screen: Blood group / Rhesus / Red Cell Antibodies
- Full blood picture (Hb, MCV, platelets)
- Haemagglutination
- Ferritin and Vitamin D
- Infections
- Random BGL - As well as disease (non-pregnancy) screening
Screening Checklist
- First Trimester?
- Second Trimester?
- Third Trimester?
- Newborn?
Flowchart: Methods of induction of labour - 4 options?
- Prostaglandins
- Balloon catheter
- Artificial rupture of membranes (‘breaking your waters’)
- Syntocinon
Methods for IOL?
- 3 Clinical risks of IOL & their management?
Macrosomia
- Definition?
- 8 Maternal risk factors?
- 1 Fetal risk factor?
- Management?
Risk Factors for Macrosomia
Maternal
1. Pre-existing diabetes or gestational diabetes
2. Race
3. Pre-pregnancy body mass index (BMI)/ maternal obesity
4. Prior history of LGA/ macrosomia
5. Maternal age > 30yr
6. High parity
7. Post term pregnancy
8. Excessive maternal weight gain.
Fetal - Male infant
What is the ‘active management of labour’?
- History?
- 4 Organisational components?
- 5 Medical components?
The active management of labour is a source of great controversy, perhaps because there may be misunderstandings of what it actually is. Synonyms frequently misused are: operative delivery, aggressive induction protocols, early amniotomy and epidural analgesia. It is in fact a system designed to ensure labour progression and intervention to decrease dystocia.
What is a partogram?
- 5 Key points from the KEMH Clinical Guidelines on the ‘Use of a Partogram’?
How does the ‘Active management of labour’ differ for Nulliparity Vs multiparity?
What medication is used for ripening the cervix prior to the induction of labour?
- 3 recommendations regarding its use?
Prostaglandins
Vaginal prostaglandin E2 has been shown to be efficacious in ripening the cervix prior to the induction of labour, they are not used for augmentation of labour. There is the evidence of increased rates of uterine hyperstimulation with fetal heart rate changes.
What is Oxytocin used for during labour?
- 2 Absolute contraindications?
- 3 Relative contraindications?
- 3 things to do prior to commencing?
- Oxytocin is used for induction or augmentation of labour in the right circumstances and only after an amniotomy has been performed.
- The dose of oxytocin should be titrated against uterine contractions. The aim is to achieve a frequency of one contraction every 2-3mins, lasting 60 secs using the minimum dose possible.
