Labour and Delivery Flashcards
Prophylaxis of preterm labour
- Vaginal progesterone
- Cervical cerclage (stitch in cervix)
Diagnosis of preterm prelabour rupture of membranes
- Speculum examination (amniotic fluid pooling in the vagina)
If doubt:
* Insulin-like growth factor-binding protein-1 (IGFBP-1) is a protein present in high concentrations in amniotic fluid
* Placental alpha-microglobin-1 (PAMG-1) is a similar alternative to IGFBP-1
Management of preterm prelabour rupture of membranes
- Prophylactic antibiotics (to prevent chorioamnionitis) - erythromycin 250mg QDS 10 days
- Induction of labour (from 34 weeks)
Define preterm prelabour rupture of membranes
Preterm prelabour rupture of membranes is where the amniotic sac ruptures, releasing amniotic fluid, before the onset of labour and in a preterm pregnancy (under 37 weeks gestation)
What is preterm labour with intact membranes
Preterm labour with intact membranes = involves regular painful contraction + cervical dilation - without the rupture of the amniotic sac
How is preterm labour with intact membranes diagnosed?
Speculum examination to assess cervical dilatation
- Less than 30 weeks gestation: Clinical assessment alone IS enough to offer management of preterm labour
- More than 30 weeks gestation: transvaginal ultrasound to assess cervical length (less than 15mm - management is offered; more than 15mm - preterm labour is unlikely)
Fetal firbonectin = alternative to vaginal USS
Fetal fibronectin is the “glue” between the chorion and the uterus, and is found in the vagina during labour. A result of less than 50 ng/ml is considered negative, and indicates that preterm labour is unlikely.
Management of preterm labour with intact membranes
- 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 and which medication is used?
Tocolysis = medications to stop uterine contractions
* Nifedipine = calcium channel blcoker
* Atosiban = oxytocin receptor antagonist (alternative to nifedipine)
Tocolysis = used between 24 and 33+6 weeks gestation in preterm labour - to delay delivery + buy time for future fetal development + administration of maternal steroids
Used as short term measure (less than 48 hours)
Why are antenatal steroids given and when?
Giving the mother corticosteroids = helps develop the fetal lungs → reduce respiratory distress syndrome after delivery
Used in women with suspected preterm labour of babies less than 36 weeks gestation
E.g. 2 doses of intramuscular betamethasone (24 hours apart)
Why is IV magnesium sulfate given during premature delivery ?
- Giving the mother IV magnesium sulfate = helps to protect the fetal brain during preterm delivery
- Reduces risk + severity of cerebral palsy
- Magnesium sulfate = given within 24 hours of delivery of delivery of preterm babies of less than 34 weeks of gestation
Mothers need close monitoring for magnesium toxicity at least four hourly. This involves close monitoring of observations, as well as tendon reflexes (usually patella reflex). Key signs of toxicity are:
- Reduced respiratory rate
- Reduced blood pressure
- Absent reflexes
IV magnesium sulfate = given as bous - followed by an infusion for up to 24 hours or until birth
Indications for an elective cesarean section
- Previous caesarean
- Symptomatic after a previous significant perineal tear
- Placenta praevia
- Vasa praevia
- Breech presentation
- Multiple pregnancy
- Uncontrolled HIV infection
- Cervical cancer
What anaesthetic is used for an elective C-section?
Spinal anaesthetic
Injection of a local anaesthetic (such as lidocaine) into the cerebrospinal fluid at the lower back. This blocks the nerves from the abdomen downwards.
When in gestation is an elective c-section performed?
From 39 weeks if possible
The 4 categories of an emergency caesarean section
- Category 1: There is an immediate threat to the life of the mother or baby. Decision to delivery time is 30 minutes.
- Category 2: There is not an imminent threat to life, but caesarean is required urgently due to compromise of the mother or baby. Decision to delivery time is 75 minutes.
- Category 3: Delivery is required, but mother and baby are stable.
- Category 4: This is an elective caesarean, as described above.
What is the most commonly used skin incision in an caesarean section?
Transverse lower uterine segment incision
The two possible incisions in a caesarean section
- Pfannenstiel incision is a curved incision two fingers width above the pubic symphysis
- Joel-cohen incision is a straight incision that is slightly higher (this is the recommended incision)
When is a vertical incision used in a caesarean section?
- Very premature deliveries
- Anterior placenta praevia
Layers of the abdomen that need to be dissected during a caesarean section
- Skin
- Subcutaneous tissue
- Fascia / rectus sheath (the aponeurosis of the transversus abdominis and external and internal oblique muscles)
- Rectus abdominis muscles (separated vertically)
- Peritoneum
- Vesicouterine peritoneum (and bladder) – the bladder is separated from the uterus with a bladder flap
- Uterus (perimetrium, myometrium and endometrium)
- Amniotic sac
The baby is delivered by hand with the assistance of pressure on the fundus. Forceps may be used if necessary.
The uterus is closed inside the abdomen using two layers of sutures. Exteriorisation (taking the uterus out of the abdomen) is avoided if possible. The abdomen and skin are then closed.
Risks of anaesthetic
- Allergic reactions or anaphylaxis
- Hypotension
- Headache
- Urinary retention
- Nerve damage (spinal anaesthetic)
- Haematoma (spinal anaesthetic)
- Sore throat (general anaesthetic)
- Damage to the teeth or mouth (general anaesthetic)
Measures to reduce the risk of complications during a caesarian section
- H2 receptor antagonists (e.g. ranitidine) or proton pump inhibitors (e.g. omeprazole) before the procedure
- Prophylactic antibiotics during the procedure to reduce the risk of infection
- Oxytocin during the procedure to reduce the risk of postpartum haemorrhage
- Venous thromboembolism (VTE) prophylaxis with low molecular weight heparin
Why is oxytocin given during an caesarean section?
Reduce the risk of a postpartum haemorrhage
Why are PPIs (e.g. omeprazole) or H2 receptor antagonists (e.g. ranitidine) given before a caesarean section?
To reduce the risk of aspiration pneumonitis during the c-section - caused by acid reflux + aspiration during the prolonged period of lying down
Risks of c-section, what are the….:
- General surgical risks
- Damage to local structures
General surgical risks:
- Bleeding
- Infection
- Pain
- Venous thromboembolism
Damage to local structures:
- Ureter
- Bladder
- Bowel
- Blood vessels
What are some complications in the postpartum period that can occur after a c-section?
- Post-partum haemorrhage
- Wound infection
- Wound dehiscence
- Endometritis
Name 3 effects on the adbominal organs that can occur as a result of a c-section
- Ileus
- Adhesions
- Hernias
What are the:
- Effects on future pregnancies
- Effects on the baby
As a result of a c-section?
Effects on future pregnancies:
* Increased risk of repeat caesarean
* Increased risk of uterine rupture
* Increased risk of placenta praevia
* Increased risk of stillbirth
Effects on the baby:
* Risk of lacerations (about 2%)
* Increased incidence of transient tachypnoea of the newborn
Can you have a vaginal birth after a caesarean section?
Yes!
**Vaginal birth after caesarean (VBAC) **
* Success rate = 75%
* Uterine rupture risk 0.5%
Contraindications for a VBAC
- Previous uterine rupture
- Classical caesarean scar (a vertical incision)
- Other usual contraindications to vaginal delivery (e.g. placenta praevia)
Having a caesarean section is likely to lead to a period of reduced mobility. Women should have a VTE risk assessment performed to determine the type and duration of VTE prophylaxis (follow local guidelines).
Prophylaxis for VTE involves….
- Early mobilisation
- Anti-embolism stockings or intermittent pneumatic compression of the legs
- Low molecular weight heparin (e.g. enoxaparin)
Define postpartum haemorrhage
Bleeding after the delivery of baby + placenta
Postpartum haemorrhage = most common cause of obstetric haemorrhage, potential cause of maternal death
To be classified as postpartum haemorrhage, there needs to be a loss of:
- 500ml after a vaginal delivery
- 1000ml after a caesarean section