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3A Womens health > Instrumental delivery > Flashcards

Instrumental delivery Flashcards

1
Q

What is an instrumental delivery?

A

Instrumental delivery refers to a vagina delivery assisted by either a ventouse suction cup or forceps. Tools are used to help deliver the baby’s head.

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2
Q

What percentage of births in the UK are assisted by instrumental delivery?

A

10%

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3
Q

What is recommended after instrumental delivery?

A

Co-amoxiclav
Reduces the risk of maternal infection

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4
Q

What are the indications to perform an instrumental delivery?

A
  • Failure to progress
  • Fetal distress
  • Maternal exhaustion
  • Control of the head in various fetal positions
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5
Q

What does instrumental delivery increase the risk of the mother for?

A
  • Postpartum haemorrhage
  • Episiotomy
  • Perineal tears
  • Injury to the anal sphincter
  • Incontinence of the bladder or bowel
  • Nerve injury (obturator or femoral nerve)
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6
Q

What are the key risks that a baby might have with an instrumental delivery?

A
  • Cephalohaematoma with ventouse
  • Facial nerve palsy with forceps
  • Subgaleal haemorrhage (most dangerous)
  • Intracranial haemorrhage
  • Skull fracture
  • Spinal cord injury
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7
Q

What is ventouse and what is the main complication for the baby?

A

A ventouse is essentially a suction cup on a cord. The suction cup goes on the baby’s head, and the doctor or midwife applies careful traction to the cord to help pull the baby out of the vagina.

The main complication for the baby is cephalohaematoma. This involves a collection of blood between the skull and the periosteum.

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8
Q

What is forceps and its main complications?

A

Forceps look like large metal salad tongs. They come as two pieces of curved metal that attach together, go either side of the baby’s head and grip the head in a way that allows the doctor or midwife to apply careful traction and pull the head from the vagina.

The main complication for the baby is facial nerve palsy, with facial paralysis on one side.

Forceps delivery can leave bruises on the baby’s face. Rarely the baby can develop fat necrosis, leading to hardened lumps of fat on their cheeks

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9
Q

What nerve injuries can be caused by instrumental delivery?

A
  • Resolves over 6-8 weeks
  • Femoral nerve
  • Obturator nerve
  • Lateral cutaneous nerve of the thigh
  • Lumbosacral plexus
  • Common peroneal nerve
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10
Q

What happens with the femoral nerve in ID?

A

The femoral nerve may be compressed against the inguinal canal during a forceps delivery. Injury to this nerve causes weakness of knee extension, loss of the patella reflex and numbness of the anterior thigh and medial lower leg.

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11
Q

What happens with the obturator nerve in ID?

A

The obturator nerve may be compressed by forceps during instrumental delivery or by the fetal head during normal delivery. Injury causes weakness of hip adduction and rotation, and numbness of the medial thigh.

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12
Q

What happens with the lateral cutaneous nerve of the thigh in ID?

A

The lateral cutaneous nerve of the thigh runs under the inguinal ligament. Prolonged flexion at the hip while in the lithotomy position can result in injury, causing numbness of the anterolateral thigh.

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13
Q

What happens with the lumbosacral plexus in ID?

A

The lumbosacral plexus may be compressed by the fetal head during the second stage of labour. Injury to this network of nerves nerve can cause foot drop and numbness of the anterolateral thigh, lower leg and foot.

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14
Q

What happens with the common peroneal nerve in ID?

A

The common peroneal nerve may be compressed on the head of the fibula whilst in the lithotomy position. Injury to this nerve causes foot drop and numbness in the lateral lower leg.

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15
Q

What is the definition of placenta accreta?

A

Placenta accreta refers to when the placenta implants deeper, through and past the endometrium, making it difficult to separate the placenta after delivery of the baby. It is referred to as placenta accreta spectrum

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16
Q

What are the 3 layers of the uterine wall?

A
  • Endometrium, the inner layer that contains connective tissue (stroma), epithelial cells and blood vessels
  • Myometrium, the middle layer that contains smooth muscle
  • Perimetrium, the outer layer, which is a serous membrane similar to the peritoneum (also known as serosa)
  • Usually the placenta attaches to the endometrium. This allows the placenta to separate cleanly during the third stage of labour, after delivery of the baby.
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17
Q

What is the pathophysiology of placenta accreta?

A

With placenta accreta, the placenta embeds past the endometrium, into the myometrium and beyond. This may happen due to a defect in the endometrium. Imperfections may occur due to previous uterine surgery, such as a caesarean section or curettage procedure. The deep implantation makes it very difficult for the placenta to separate during delivery, leading to extensive bleeding (postpartum haemorrhage).

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18
Q

What are the 3 further definitions of placenta accreta?

A

Superficial placenta accreta is where the placenta implants in the surface of the myometrium, but not beyond
Placenta increta is where the placenta attaches deeply into the myometrium
Placenta percreta is where the placenta invades past the myometrium and perimetrium, potentially reaching other organs such as the bladder

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19
Q

What are the RFs for Placenta accreta?

A
  • Previous placenta accreta
  • Previous endometrial curettage procedures (e.g. for miscarriage or abortion)
  • Previous caesarean section
  • Multigravida
  • Increased maternal age
  • Low-lying placenta or placenta praevia
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20
Q

What are the S + S of Placenta accreta?

A

Placenta accreta does not typically cause any symptoms during pregnancy. It can present with bleeding (antepartum haemorrhage) in the third trimester.

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21
Q

Investigations for placenta accreta

A

It may be diagnosed on antenatal ultrasound scans, and particular attention is given to women with a previous placenta accreta or caesarean during scanning.

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22
Q

What does placenta accreta a big significant factor for?

A

PPH

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23
Q

What is the management of placenta accreta?

A

Ideally, placenta accreta is diagnosed antenatally by ultrasound. This allows planning for birth.

MRI scans may be used to assess the depth and width of the invasion.

A specialist MDT should manage women with placenta accreta. Patients may require additional management at birth due to the risk of bleeding and difficulty separating the placenta

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24
Q

What is the additional management that might have to be done for placenta accreta?

A
  • Complex uterine surgery
  • Blood transfusions
  • Intensive care for the mother
  • Neonatal intensive care
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25
Q

When is delivery planned for those with placenta accreta?

A

Delivery is planned between 35 to 36 + 6 weeks gestation to reduce the risk of spontaneous labour and delivery. Antenatal steroids are given to mature the fetal lungs before delivery.

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26
Q

What are the options that someone has during CS for placenta accreta?

A
  • Hysterectomy with the placenta remaining in the uterus (recommended)
  • Uterus preserving surgery, with resection of part of the myometrium along with the placenta
  • Expectant management, leaving the placenta in place to be reabsorbed over time
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27
Q

What is the expectant management for placenta accreta?

A

Expectant management comes with significant risks, particularly bleeding and infection.

The RCOG guideline (2018) suggests that if placenta accreta is seen when opening the abdomen for an elective caesarean section, the abdomen can be closed and delivery delayed whilst specialist services are put in place. If placenta accreta is discovered after delivery of the baby, a hysterectomy is recommended.

28
Q

What is the definition of placenta praevia?

A

where the placenta is attached in the lower portion of the uterus, lower than the presenting part of the fetus

29
Q

What are the RCOG definitions for placenta praevia?

A

Low-lying placenta is used when the placenta is within 20mm of the internal cervical os
Placenta praevia is used only when the placenta is over the internal cervical os

30
Q

What is the incidence of placenta praevia?

A

1% of pregnancies

31
Q

What is placenta praevia a notable cause of?

A

Antepartum haemorrhage

32
Q

What are the risks of placenta praevia?

A

Placenta praevia is associated with increased morbidity and mortality for the mother and fetus. The risks include:

  • Antepartum haemorrhage
  • Emergency caesarean section
  • Emergency hysterectomy
  • Maternal anaemia and transfusions
  • Preterm birth and low birth weight
  • Stillbirth
33
Q

What are the 4 grades of placenta praevia?

A

Minor praevia, or grade I – the placenta is in the lower uterus but not reaching the internal cervical os
Marginal praevia, or grade II – the placenta is reaching, but not covering, the internal cervical os
Partial praevia, or grade III – the placenta is partially covering the internal cervical os
Complete praevia, or grade IV – the placenta is completely covering the internal cervical os

34
Q

What are the RFs for placenta praevia?

A
  • Previous caesarean sections
  • Previous placenta praevia
  • Older maternal age
  • Maternal smoking
  • Structural uterine abnormalities (e.g. fibroids)
  • Assisted reproduction (e.g. IVF)
35
Q

What are the investigations for placenta praevia?

A
  • history and examination
    there is usually no associated hypertension
    unengaged presenting part
  • ultrasound; transvaginal ultrasonic examination is reported to have improved diagnostic accuracy, but it is not a routine procedure
  • The 20-week anomaly scan is used to assess the position of the placenta and diagnose placenta praevia.
36
Q

What are the S + S of placenta praevia?

A

Many women with placenta praevia are asymptomatic. It may present with painless vaginal bleeding in pregnancy (antepartum haemorrhage). Bleeding usually occurs later in pregnancy (around or after 36 weeks).
Amount of blood lost highly variable
On exam - uterus relaxed and fetal parts palpable

37
Q

Why should you not perform a vaginal examination on someone with placenta praevia?

A

DO NOT PERFORM A VAGINAL EXAMINATION as severe haemorrhage may be provoked by disturbing blood vessels lying across the os.

38
Q

What is the management of low-lying placenta or placenta praevia diagnosed in early pregnancy?

A

the RCOG guideline (2018) recommends a repeat transvaginal ultrasound scan at:

32 weeks gestation
36 weeks gestation (if present on the 32-week scan, to guide decisions about delivery)

39
Q

What is the management of placenta praevia?

A

Corticosteroids are given between 34 and 35 + 6 weeks gestation to mature the fetal lungs, given the risk of preterm delivery.

Planned delivery is considered between 36 and 37 weeks gestation. It is planned early to reduce the risk of spontaneous labour and bleeding. Planned cesarean section is required with placenta praevia and low-lying placenta (<20mm from the internal os).

40
Q

When is emergency CS needed?

A

may be required with premature labour or antenatal bleeding.

41
Q

What is the main complication of placenta praevia and what is the urgent management required?

A

Haemorrhage before, during and after delivery
Involve:
Emergency caesarean section
Blood transfusions
Intrauterine balloon tamponade
Uterine artery occlusion
Emergency hysterectomy

42
Q

How does placenta praevia cause haemorrhage?

A

Uterine contractions result in the shearing off of the placenta from the myometrium and the decidua. As a result, the closer to term, the larger the amount of bleeding.

43
Q

What does NICE suggest about placenta praevia?

A

because most low-lying placentas detected at the routine anomaly scan will have resolved by the time the baby is born, only a woman whose placenta extends over the internal cervical os should be offered another transabdominal scan at 32 weeks. If the transabdominal scan is unclear, a transvaginal scan should be offered

44
Q

What is the aetiology of placenta praevia?

A

Placenta praevia may be the result of low implantation of the blastocyst or fusion of the decidua capsularis with the decidua vera. After low implantation placenta praevia is not inevitable, and ultrasound examination has shown the majority of such cases to either abort or resolve as the uterus grows.

A large placenta can causes placenta praevia as its lower portion completely or partially overlaps the internal os.

Atrophy and inflammation, perhaps secondary to previous caesarian section, causes defective decidual vascularisation and hence placenta praevia.

45
Q

RFs for placenta praevia

A

past history of placenta praevia
a large placenta, e.g. with fetal erythroblastosis and multiple pregnancies
high parity
an abnormal uterus e.g. fibroids
previous caesarian section

46
Q

What is the prognosis for placenta praevia?

A

Placenta praevia is not usually dangerous for the mother or the baby: a far greater risk prevails for abruption of the placenta. Postpartum haemorrhage is more common with placenta praevia because of the reduced ability for the lower segment to retract.

Over 50% of patients are close to term when bleeding occurs, and the majority of these are managed conservatively. Generally, it is the mothers with excessive haemorrhage, and more rarely premature labour, that must be delivered.

Premature babies are more common within a placenta praevia population than in the general population, and they have a greater morbidity and mortality.

47
Q

What is placental abruption?

A

Placental abruption refers to when the placenta separates from the wall of the uterus during pregnancy. The site of attachment can bleed extensively after the placenta separates.

48
Q

What is the pathophysiology of placental abruption?

A

Pathological separation of the placenta from its uterine attachment results in a maternal bleed from the opened sinuses.

Initially, the decidua basalis splits, leaving a thin layer adherent to the myometrium. A decidual haematoma is formed with destruction of adjacent placenta.

49
Q

What is the spectrum of presentation for placental abruption?

A

concealed - no actual bleeding is seen - it remains in the uterus
revealed - blood tracks between the membranes and the uterus and escapes vaginally
mixed - most usual

50
Q

What is the epidemiology of placental abruption?

A

Abruption occurs in about 1:200 pregnancies, but frequencies as high as 1:75 have been recorded.

The reasons for this discrepancy reside with the tendency for different populations of mothers to present at different times after symptoms such as abdominal pain, and the variation of diagnostic criteria between centres.

51
Q

What is placental abruption a significant cause of?

A

PPH

52
Q

What are the RFs for placental abruption?

A

Previous placental abruption
Pre-eclampsia
Bleeding early in pregnancy
Trauma (consider domestic violence)
Multiple pregnancy
Fetal growth restriction
Multigravida
Increased maternal age
Smoking
Cocaine or amphetamine use
multiple pregnancies

53
Q

S + S of placental abruption? None may be present or only a few for milder cases

A

Sudden onset severe abdominal pain that is continuous
Vaginal bleeding (antepartum haemorrhage)
Shock (hypotension and tachycardia)
Abnormalities on the CTG indicating fetal distress
Characteristic “woody” abdomen on palpation, suggesting a large haemorrhage
uterine tenderness and back pain
fetal distress
high frequency uterine contractions of low tone
idiopathic preterm labour
hypotension leading to rapid shock

54
Q

In extreme placental abruption what are the signs and symptoms?

A

profuse abruption, pain, shock, uterine rigidity and absent fetal heart sounds are evident

55
Q

DDs of placental abruptions

A

Placenta praevia

56
Q

RCOG severity of antepartum haemorrhage?

A

Spotting: spots of blood noticed on underwear
Minor haemorrhage: less than 50ml blood loss
Major haemorrhage: 50 – 1000ml blood loss
Massive haemorrhage: more than 1000 ml blood loss, or signs of shock

57
Q

What do the clinical features of placental abruption depend on?

A

size and site of the bleeding. A bleed which tracks down behind the membranes and appears through the cervix is said to be ‘revealed’; that which occurs retroplacentally, is said to be ‘concealed’.

58
Q

What are the grades of haemorrhage for placental abruption?

A

mild - in this case there is only a small area of placental separation and the blood loss is usually less than 200ml. There may be abdominal discomfort and the uterus may be tender
moderate - up to a 1/3 of the placenta separates. There is more severe bleeding (200-600 ml). The patient complains of abdominal pain. On examination the patient may have tachycardia but does not have signs of hypovolaemia. The uterus is tender. Fetal heart sounds are present
severe - in this condition more than half of the placenta separates. The abdominal pain is more severe. On examination the uterus is tender and rigid - it may be impossible to feel the fetus. Fetal heart sounds are reduced or absent. The patient may be in a state of hypovolaemic shock

59
Q

What is concealed abruption?

A

Concealed abruption is where the cervical os remains closed, and any bleeding that occurs remains within the uterine cavity. The severity of bleeding can be significantly underestimated with concealed haemorrhage.

Concealed abruption is opposed to revealed abruption, where the blood loss is observed via the vagina.

60
Q

What are the investigations for placental abruption?

A

There are no reliable tests for diagnosing placental abruption. It is a clinical diagnosis based on the presentation.

61
Q

Placental abruption is an obstetric emergency - what does the urgency depend on?

A

amount of placental separation, extent of bleeding, haemodynamic stability of the mother and condition of the fetus. It is important to consider concealed haemorrhage, where the vaginal bleeding may be disproportionate to the uterine bleeding.

62
Q

What are the initial steps with major or massive haemorrhage?

A

Urgent involvement of a senior obstetrician, midwife and anaesthetist
2 x grey cannula
Bloods include FBC, UE, LFT and coagulation studies
Crossmatch 4 units of blood
Fluid and blood resuscitation as required
CTG monitoring of the fetus
Close monitoring of the mother

63
Q

What are some other management that needs to be done for placental abruption

A

Ultrasound can be useful in excluding placenta praevia as a cause for antepartum haemorrhage, but is not very good at diagnosing or assessing abruption.

Antenatal steroids are offered between 24 and 34 + 6 weeks gestation to mature the fetal lungs in anticipation of preterm delivery.

Rhesus-D negative women require anti-D prophylaxis when bleeding occurs. A Kleihauer test is used to quantify how much fetal blood is mixed with the maternal blood, to determine the dose of anti-D that is required.

Emergency caesarean section may be required where the mother is unstable, or there is fetal distress.

64
Q

What is there an increased risk of with placental abruption?

A

There is an increased risk of postpartum haemorrhage after delivery in women with placental abruption. Active management of the third stage is recommended.

65
Q

For placenta praevia and abruption what should you not do?

A

DIGITAL EXAMINATION

3A Womens health (33 decks)

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