Antepartum haemorrhage Flashcards

1
Q

What is antepartum haemorrhage?

A

Bleeding from the genital tract after 24 weeks gestation.

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2
Q

What are the causes of APH?

A

Common: undetermined origin, placental abruption, placenta praaevia
Uncommon: incidental genital tract pathology, uterine rupture, vasa praaevia and placenta praevia

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3
Q

What is placenta praaevia?

A

Placenta praevia occurs when the placenta is implanted in the lower segment of the uterus.

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4
Q

Why does the placenta tend to move during the pregnancy?

A

Because of the formation of the lower segment of the uterus in the third trimester: it is the myometrium where the placenta implants that moves away from he internal cervical os.

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5
Q

How (not into what) is placenta praevia classified?

A

According to the proximity of the placenta to the internal os of the cervix. It may be predominantly on the anterior or posterior uterine wall.

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6
Q

What is a marginal placenta praevia?

A

Placenta in lower segment, not over os

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7
Q

What is a major placenta praevia?

A

Placenta completely or partially covering the os

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8
Q

What risk factors are there for placenta praevia?

A

Twins, high parity and age, scarred uterus

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9
Q

What complications occur due to a placenta praevia?

A

The placenta in the lower segment obstructs engagement of the head. Haemorrhage can be severe.

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10
Q

Why is there haemorrhage in placenta praevia?

A

The lower segment of the uterus is unable to contract and constrict the maternal blood supply so the haemorrhage can be severe and may continue during and after delivery.

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11
Q

What is placenta accreta?

A

Placenta accreta occurs when all or part of the placenta attaches abnormally to the myometrium (the muscular layer of the uterine wall).

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12
Q

How does placenta praevia lead to placenta accreta?

A

If a placenta implants into a previous C section scar, it may be so deep as to prevent placental separation

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13
Q

What is placenta percreta?

A

When the placenta invades through the uterine wall and into surrounding structures such as the bladder

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14
Q

What are the clinical features of placenta praevia?

A

Intermittent painless bleeds, which increase in frequency and intensity over several weeks. Such bleeding may be severe. 1/3 of women do not experience bleeding.

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15
Q

What would you find on examination of placenta praevia?

A

Breech presentation and transverse lie are common. The fetal head is not engaged and high. Vaginal examination can provoke massive bleeding and is never performed in a woman who is bleeding vaginally until exclusion of placenta praevia.

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16
Q

How do you investigate placenta praevia?

A

US, CTG to assess fetal well-being

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17
Q

How do you manage placenta praevia?

A

Admission in all women with bleeding. Often after confirmation, women are admitted until delivery due to bleeding risk. Blood is kept available, potential anti-D and steroids

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18
Q

How are placenta praevias delivered?

A

Elective C section at 39 weeks by most senior doctor available. Bleeding is common. Uterine incision is made away from the placenta.

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19
Q

What is placental abruption?

A

Placental abruption is when part (or all) of the placenta separates before delivery the fetus. It occurs in 1% of pregnancies.

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20
Q

What is the pathology of placental abruption?

A

When part of the placenta separates, considerable maternal bleeding may occur behind it. Further placental separation and acute fetal distress may follow.

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21
Q

Where does the blood from the placental separation usually go in a placental abruption?

A

Blood usually tracks down between the membranes and the myometrium to be revealed as an APH. It may also enter the liquor or it may just enter the myometrium.

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22
Q

Is APH always visible?

A

No, it 20% it is absent as the blood only enters the myometrium.

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23
Q

What are the complications of APH?

A

Fetal death (30%); blood transfusions; DIC and renal failure may rarely lead to maternal death

24
Q

What are the risk factors of APH?

A

IUGR, PE, autoimmune disease, maternal smoking, cocaine usage, previous history of placental abruption, multiple pregnancy, high maternal parity, trauma

25
Q

What are the clinical features of APH?

A

Painful bleeding with dark blood.

26
Q

Why do you get pain with APH?

A

Due to blood behind the placenta and in the myometrium

27
Q

Does the degree of vaginal bleeding reflect the severity of the abruption?

A

No, because some may not escape from the uterus.

28
Q

What is the difference between a concealed APH and a revealed APH?

A

If pain occurs alone, the abruption is concealed. If vaginal bleeding is evident, it is revealed.

29
Q

What would you find on examination of APH?

A

Tachycardia and hypotension after massive bloodless. The uterus is often tender and contracting, labour often ensues. In severe cases, the uterus is ‘woody’ hard and the foetus is difficult to feel. Fetal heart tones are often abnormal or absent.

30
Q

What investigations would you perform in APH?

A

CTG to establish fetal wellbeing. US to rule out placenta praevia. FBC, coagulation screen and cross match, catheterisation with measured urine output, U&E to establish maternal wellbeing.

31
Q

How do you manage APH?

A

Admission is required, IV fluids and potentially steroids and anti-D. If fetal distress, deliver immediately. If no fetal distress and >37 weeks, induce and monitor closely. If no fetal distress and <37 weeks, mother is monitored closely on the ward.

32
Q

Does APH increase the risk of PPH?

A

Yes

33
Q

What are the causes of APH?

A

Placenta praevia, bleeding of undetermined origin, ruptured vasa praevia, uterine rupture, bleeding of gynaecological origin

34
Q

What is vasa praevia?

A

It occurs when a fetal blood vessel runs in the membranes in front of the present part. Tends to occur when the umbilical cord is attached to the membranes rather than the placenta

35
Q

What is the typical presentation of vasa praevia?

A

Painless, moderate vaginal bleeding at amniotomoy or spontaneous rupture of the membranes, which is accompanied by severe fetal distress, C section is often no quick enough to save the foetus.

36
Q

What are the prinicipal causes of perinatal mortality?

A

Unexplained; preterm delivery; IUGR; congenital abnormalities; intrapartum, including hypoxia; placental abruption

37
Q

What is small for gestational age? (SGA)

A

The weight of the fetus is less than the tenth gentile for its gestation.

38
Q

What is fetal distress?

A

An acute situation, such as hypoxia, that may result in fetal damage or death if it is not reversed, or if the fetus is delivered urgently.

39
Q

What is fetal compromise?

A

A chronic situation, when conditions for the normal growth and neurological development are not optimal (poor nutrient transport/placental dysfunction)

40
Q

What are the aims of fetal surveillance?

A

Identify high risk pregnancy; monitor fetal growth and wellbeing; intervene at an appropriate time

41
Q

What are the problems with fetal surveillance?

A

All methods have a false positive rate, the ‘medicalise’ pregnancy.

42
Q

What are some prepregnancy identifications of high risk pregnancy?

A

Poor past obs history; maternal disease; assisted conception; extremes of reproductive age; heavy smoking; drug abuse

43
Q

What are some identifications of high risk pregnancy during the pregnancy?

A

HTN/proteinuria; vaginal bleeding; SGA; prolonged pregnancy; multiple pregnancy

44
Q

Does the abdomen or head stop growing first in IUGR?

A

The abdomen, resulting in a ‘thin’ fetus or ‘asymetrical’ growth restriction

45
Q

What is and why do we use a doppler artery waveform?

A

It is used to measure velocity waveforms in the umbilical arteries.

46
Q

What is an abnormal uterine artery doppler?

A

Evidence of a high resistance circulation, i.e. reduced flow in fetal diastole compared to systole suggests placental dysfunction.

47
Q

Which arteries does a doppler look at when looking at the fetal circulation?

A

Middle cerebral artery and the ductus venous.

48
Q

What would an abnormal fetal circulation doppler show?

A

In fetal compromise, the MCA develops a low resistance pattern in comparison to the thoracic aorta, which reflects a head-sparing effect.

49
Q

What are some physiological causes of a small baby?

A

Low maternal height and weight, nulliparity, asian, female fetal gender.

50
Q

What are some pathological causes of SGA?

A

IUGR; pre-existing maternal disease; maternal pregnancy complications; multiple pregnancy; smoking; drug use; infection; extreme malnutrition; congenital abnormalities;

51
Q

What are the complications of SGA?

A

Increased risk of cerebral palsy, preterm delivery and maternal complications

52
Q

What would you find on US of SGA?

A

Small baby; abnormal umbilical artery doppler; reduced amniotic fluid (oligohydramnios), head-sparing MCA doppler.

53
Q

What is a prolonged pregnancy?

A

If the pregnancy is prolonged over 42 weeks gestation.

54
Q

At what gestation after term does increased perinatal mortality risk occur?

A

Between 41 and 42 weeks.

55
Q

What are the risk factors for prolonged pregnancy?

A

Previous prolonged pregnancy; in nulliparous women; rarer in south asian and black women

56
Q

What are the risks of prolonged pregnancy?

A

Stillbirth; neonatal illness and encephalopathy; meconium passage; fetal distress.

57
Q

At what gestation would you normally induce labour?

A

Between 41 and 42 weeks, before 41 weeks it does not have as many benefits. ‘Sweeping’ the cervix helps spontaneous labour start earlier.