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Obstetrics & Gynaecology > Abnormal delivery > Flashcards

Abnormal delivery Flashcards

1
Q

Define preterm labour

A

Baby delivered after 24 weeks and before 37 weeks

7-8% of babies born in UK

Categories:

  • Moderate to late: 32-37 weeks
  • Very preterm: 28-32 weeks
  • Extremely preterm: <28 weeks
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2
Q

At what stage is a foetus viable?

A

24 weeks with a birthweight >500g. Resuscitation is considered for babies between 23-24 weeks but survival is frequently complicated

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3
Q

Aetiology of pre term labour

A

Spontaneous or due to medical intervention

Exact cause is unknown but risk factors include

  • Previous preterm baby (strongest risk factor)
  • Multiple pregnancies
  • Short interval between pregnancies
  • Low BMI
  • Smoking
  • Infection
  • Previous cervical trauma or surgery
  • Antepartum haemorrhage
  • Black women (16-18% compared to 5-9% white)
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4
Q

Prevention of preterm labour

A

Women with risk factors are referred early in pregnancy to socialist clinics. Women with cervix <25mm long are at higher risk of preterm birth

  • Cervical suture is put in place to prevent delivery <24 weeks = cervical cerclage
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5
Q

Indications for cervical stitch

A
  • Hx of >3 preterm births
  • Cervical shortening to 25mm on USS
  • Premature cervical dilation with exposed foetal membranes

*if premature delivery occurs despite stitch, abdo stitch is put in place for subsequent pregnancies

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6
Q

Diagnosis and investigation of preterm labour

A

Diagnosis:

  • Cervical dilation assessed digitally or visualised with speculum
  • Premature labour diagnosed when cervix >3cm

Investigations used to diagnose premature labour of cervix not dilated:

  • Fibronectin test or actim partus test used to predict preterm births. The proteins detected leak from the uterus when the decidua and chorion start to detach in premature labour. The tests reduce unnecessary medical intervention and conserve resources
  • Urine samples and vaginal swabs are used to screen for infection
  • *fibronectin swab must be taken before digital vaginal examination*
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7
Q

Management of preterm labour

A

Aim is to prolong delivery to allow administration of corticosteroids and transfer to a hospital with neonatal unit

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8
Q

Medication given during preterm labour

A

Medication: corticosteroids improve neonatal outcomes by reducing risk of neonatal death, respiratory distress syndrome, intraventricular haemorrhage, necrotising enterocolitis, systemic infections

Corticosteroids: given IM between 24-34 weeks

Tocolytics: inhibit contractions and delay delivery

Erythromycin: given for 10 days after preterm prelabour rupture of membranes to prevent infection

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9
Q

Prognosis of preterm labour

A
  • Short term risk: necrotising enterocolitis and intracranial haemorrhage
  • Long term risk: cerebral palsy, developmental delay and problems with vision and hearing
  • Chance of survival at 23 weeks: 15%
  • Chance of surgical at 25 weeks: 80%
  • Babies born <26 weeks have significant risk of disability and only 20% have no disabilities
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10
Q

What is preterm prelabour rupture of membranes (P-PROM)?

A
  • Rupture of membranes < 37w. One of the major causes of pre-term labour and holds a risk of sepsis
  • E: 2% of pregnancies, causes 40% of preterm labour
  • RF: smoking, previous preterm, vaginal bleeding in pregnancy, lower GTI infection
  • H: hx of popping sensation or waters breaking (may be described as urinary incontinence)
  • E: only do sterile speculum: yellow/brown vaginal discharge.
  • I: Infective screen (CRP/WCC), MSU, urine stick, US.
  • T: admit, monitor for chorioamnionitis > oral Erythromycin for 10d, antenatal steroids (dexamethasone), deliver at 34w.
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11
Q

What is chorioamnionitis?

A
  • Chorioamnionitis (5% of pregnancies): life threatening due to ascending bacterial infection most commonly due to PROM;
  • H: maternal pyrexia, tachycardia, foetal tachycardia with a background of PPROM that is untreated
  • deliver foetus and give IV antibiotics
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12
Q

What is cord prolapse?

A
  • Umbilical cord descends through open cervix before the foetus. Its an emergency.
  • E: more common in MP with non-cephalic presentations. 1/500 deliveries.
  • RF: prematurity, multiparity, polyhydramnios, twin pregnancies, cephalopelvic disproportion, abnormal presentation, placenta praevia, long cord, high foetal station
  • H: sudden bradycardia and rupture of membranes; cord compression compromises blood supply.
  • E: feeling cord under foetus is diagnostic. Elevate foetus to relieve compression, or fill bladder with saline, put her on all 4’s with head below buttocks. Don’t touch cord.
  • T: C-section
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13
Q

What is malpresentation of the foetus?

A

Any non-cephalic presentation (any part other than the head of the foetus close to the pelvis)

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14
Q

What is breech presentation?

A

Where the bottom of the pelvis is the closest part of the foetus to the maternal pelvis

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15
Q

Vaginal delivery in malpresentation

A
  • Vaginal delivery is possible in breech but associated with increased perinatal morbidity and mortality
    • Vaginal delivery is not possible with transverse lie and brow presentation
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16
Q

Aetiology of malpresentation

A

Most cases are of unknown cause but there are predisposing factors

Maternal

  • Pelvic tumours
  • Congenital uterine anomalies
  • Oligohydramnios
  • Placenta praevia

Foetal

  • Prematurity
  • Foetal anomalies
  • Multiple pregnancies
  • Intrauterine death
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17
Q

Clinical features of malpresentation

A

Suspected antenatally on abdo palpation

Diagnosis confirmed by USS

18
Q

Management of malpresentation

A
  • External cephalic version = manipulation of the foetus into a cephalic presentation, used for breech presentation and transverse lie. 50% success rate and higher if terbutaline is used (uterine relaxant)
  • Complications are rare
  • Spontaneous reversion back to breech occurs in 3% of cases
  • Facilities for c-section must be available in case complications occur
  • Foetal heart rate is monitored before and after
  • If unsuccessful or declined, delivery is by vaginal breech or caesarean
  • Increased risk of cord prolapse with vagina delivery
19
Q

Causes of failure to progress in labour

A

Failure to progress in first two stages is the result of either

Power: efficiency of contractions, assessed by the effect the contractions have on cervical dilation. Contractions are stimulated by oxytocin so use of syntoncinon, which increases oxytocin levels) increases contraction strength and frequency.

Passenger: size, presentation or position may cause failure to progress. Passage through the canal need the foetal head to be flexed with the chin tucked in the chest = occipito-anterior

  • Malposition increases the size of the head in relation to the pelvis, causing delay

Passage: birth canal, abnormalities of the pelvis can occur due to malnutrition, trauma or polio, abnormalities of the soft tissue can occur due to tumours or scarring from FGM

20
Q

What effect does the supine position have on contractions?

A

Reduces efficiency

21
Q

What is cephalopelvic disproportion?

A

Failure of the foetal head to pass through the pelvis because of discrepancies in size

22
Q

Diagnostic approach of failure to progress in labour

A
  • Diagnosis of failure to progress is confirmed by serial vaginal examinations to assess cervical dilation and foetal descent
  • Frequency and strength of contractions are determined by abdo palpation
23
Q

Investigations for failure to progress in labour

A
  • USS to determine foetal presentation
  • Assessment of pelvic size by clinical exam or MRI is inaccurate and not done
  • Hormone-induced relaxation of ligaments and sitting or squatting increases pelvic outlet dimensions
24
Q

Management of failure to progress in labour

A

Medication: synthetic oxytocin (syntocin) used of failure to progress is confirmed. Given IV with dose increased every 30mins until 4-5 strong contractions occur in 10 mins.

  • Oxytocin causes contractions to be more painful
  • Vaginal examination is done 4h after starting oxytocin and if the cervix isn’t dilated any more than 2cm then a c-section is carried out

Operative vaginal delivery: carried out when there is delay in the second stage of labour and if the foetal head is low enough

C-section in the second stage of labour has a higher complication rate than the first stage

25
Q

How is retained placenta managed?

A

Manual removal, done by separating the placenta from the uterine wall during vaginal examination. Uncomfortable so analgesia is needed. Antibiotics used to prevent endometritis

26
Q

Define failure to progress in the first stage of labour

A
  • Suspected if <2cm dilatation in a 4 hour period
  • Slowing of Progress in a Multiparous Women
  • Confirmed if there is no change in Cervical Dilatation 2 hours after Artificial Rupture of Membranes
27
Q

Define failure to progress in the second stage of labour

A
  • Primiparous Women – Failure to Deliver within 2 hours of Active Pushing
  • Multiparous Women – Failure to Deliver within 1 hour of Active Pushing
28
Q

Define failure to progress during third stage of labour

A
  • Passive Management – Failure to Deliver within 1 hour of Birth
  • Active Management – Failure to Deliver within 30 mins of Birth

A foetus with reduced reserves of energy is unable to tolerate intermittent reduction in placental blood flow that occurs with contractions

29
Q

What can cause foetal compromise during labour?

A

Foetal compromise in labour is caused by maternal and foetal factors

Maternal factors:

  • Diabetes, hypertension and pre-eclampsia causing uteroplacental vascular disease
  • Hypotension leading to reduced placental blood flow
  • Post-term pregnancy
  • Cord prolapse

Foetal factors:

  • Multiple pregnancy
  • Growth restriction
  • Prematurity
  • Oligohydramnios
  • Sepsis
30
Q

Clinical features of foetal compromise

A
  • Reduced foetal movements as compromised foetus conserves limited energy
  • Faecal material passed by the foetus or newborn baby. Passage of meconium is normal in utero is normal for a mature GI system but is also a sign of foetal distress because hypoxia relaxes anal sphincter
  • Amniotic fluid leaking from vagina is dark green or brown
31
Q

Investigations for foetal compromise

A
  • Cardiotocography used to monitor heart rate with early and variable decelerations reflect head and cord compression during contractions
    • Pathological cardiotocograph indicates foetal hypoxia in 50% of cases
  • Foetal blood sampling carried out when the graph is pathological and delivery is not imminent - small scratch on foetal scalp and a few droplets of blood are collected in a capillary tube
  • Measurements of foetal pH and lactate are used to guide management
32
Q

Shoulder dystocia

A
  • Complication of vaginal cephalic delivery, cause of maternal/ foetal morbidity
    • associated with postpartum haemorrhage and perineal tears, brachial plexus injury
  • RF: macrosomia, high maternal BMI, DM, prolonged labour
  • H: foetal shoulder on maternal pubic symphysis
  • T: mcrobert’s manoeuvre: flexion and abduction of maternal hips
33
Q

Operative vaginal delivery

A

Required in 10-13% of births, ventouse or forceps used with the aim being to use the instrument to facilitate cardinal movements of the foetus

Indications:

Maternal:

  • Failure to progress in second stage
  • Contraindications to prolonged second stage (maternal cardiac disease)
  • Maternal fatigue

Foetal:

  • Suspected foetal compromise
34
Q

Choice of instrument in operatve vaginal delivery

A
  • Ventouse causes less perineal trauma but more likely to fail than forceps and more likely to cause neonatal cephalohaematoma and retinal haemorrhage

Contraindications to ventouse:

  • Prematurity (<34 weeks)
  • Face presentation
  • Suspected foetal bleeding
  • Maternal HIV or hep C
35
Q

Complications of operative vaginal delivery

A
  • Perineal trauma including third and fourth degree tears is common
  • Episiotomy done to widen vagina outlet
  • Post-partum haemorrhage occurs in 10-40% due to perineal trauma and uterine agony
  • Type and frequency of foetal injury depends on instrument used
  • Forceps leave marks on the gave and sometimes cause facial nerve palsies
  • Ventouse delivery results in a chignon on baby’s head (lump) that goes within 48h
  • Shoulder dystocia is more common after an operative vaginal delivery because traction applied causes foetal head to deflex and shoulders to abduct thereby widening their diameter and making entrapment in the pelvis more likely
36
Q

Rates of c-section in the UK

A
  • International consensus is that the rate of c-section is 10-15% but they are becoming more common in all income countries
  • Highest rates in Brazil where 46% of all births are c-section because of cultural and medical pressure on women to have babies at convenient times
  • In the UK - rate has doubled over past 25 years and is now 25%
37
Q

Indications for c-section

A
  • Previous c-section
  • Breech
  • Multiple pregnancy
  • Placenta previa or acreta
  • Previous third degree tear to prevent anal sphincter dysfunction
  • HIV to reduce vertical transmission
  • Maternal request
38
Q

Indications for emergency c-section

A

Foetal compromise

Failure to progress

Cord prolapse

39
Q

What is transient tachypnoea of the newborn?

A

Short term respiratory problem

Caused by increased fluid in the lungs - the fluid is normally squeezed out during vaginal delivery but this doesn’t occur with c-section

40
Q

Types of incision for c-section

A
  • Joel Cohen incision is used to enter abdomen as it is quicker and associated with less blood loss, infection and pain than a Pfannensteil’s incision, because blunt rather than sharp dissection is carried out.
  • A transverse lower segment uterine incision then allows access to foetus
  • In a classic caesarean section a vertical uterine incision in the upper segment of the uterus is made - necessary if the lower segment cannot be accessed because of fibroids or placenta previa or in cases of extreme prematurity when lower segment isn’t formed
  • Upper segment vertical incisions are associated with uterine rupture in future labours 10% rather than 1% with a transverse lower segment incision
41
Q

Complications during c-section

A

Bleeding: 4-8% lose >1000mL

Infection

Thrombosis

Pneumonitis due to anaesthetic related aspiration

Foetal laceration: 2% babies - hence blunt dissection

Damage to bladder etc

Emergency hysterectomy: 0.8%

Uterine rupture during future labour

Placenta praevia or accreta in future pregnancies

A woman trying for a vaginal birth after caesarean has a 75% chance of success if she has only had one previous c-section

Obstetrics & Gynaecology (25 decks)

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