Antepartum haemorrhage Flashcards

1
Q

What is antepartum haemorrhage?

A

Bleeding from 24 weeks gestation

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2
Q

What are the most serious causes of antepartum haemorrhage

A
  • Placental abruption (separation of placenta from uterine wall)
  • Placenta praevia (placenta partially or wholly covering cervix)
  • Placenta acreta (placenta abnormally adherent to myometrium, usually the scar from a previous c-section)
  • Vasa previa (bleeding from foetal vessels)
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3
Q

Epidemiology of antepartum haemorrhage

A
  • Bleeding after 24 weeks affects 3-5% of pregnancies
  • Associated with up to 25% preterm births
  • 30% of pregnancies affected by placenta acreta result in hysterectomy - partial detachment of the placenta causes massive haemorrhage
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4
Q

Causes of anepartum haemorrhage

A

Bleeding from external genitalia

  • Trauma, infection, vulval or vaginal cancer

Bleeding from cervix

  • ‘Show’, cervicitis, cervical polyp, cervical cancer

Bleeding from uterus

  • Placental abruption, placenta praevia and acceta, vasa praveia, uterine rupture
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5
Q

What are the risk factors for placental abruption?

A
  • Abdo trauma
  • Multiple pregnancy
  • Polyhydramnios
  • Premature rupture of membranes
  • Smoking
  • Cocaine
  • Previous abruption
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6
Q

How are placenta praevia and abruption differentiated?

A
  • Abruption presents with pain and bleeding
  • Placenta previa and vasa previa are painless bleeds
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7
Q

Diagnosis of antepartum haemorrhage

A
  • Resuscitation if needed, obs including BP, pulse and RR and the results are used to guide management
  • Abdo and speculum examinations to determine cause of bleed
  • Placental location on previous scans is reviewed
  • ** digital vaginal examination is not done until location of placenta is known because it can trigger significant bleeding in case of placenta previa **
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8
Q

Investigation of antepartum haemorrhage

A
  • USS to exclude placenta previa - not helpful for vasa previa or diagnosis of placental abruption
  • IV access is gained when blood loss >50mL
  • Bloods: cross match, FBC for anaemia, coagulation tests
  • Foetal HR monitored once mothers condition has stabilised
  • Acid elation test (Kleihauer) for rhesus negative women - results are used to guide the amount of anti-D required
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9
Q

Management of antepartum haemorrhage

A
  • Admit for significant bleeds until they have settled
  • Massive bleeding or maternal compromise - induce delivery

*antepartum haemorrhage makes post partum haemorrhage more likely so active management of third stage of labour is required*

Unexplained bleeding is associated with poor outcomes so serial screening is need to look for growth restriction and oligohydramnios

Medication: corticosteroids if significant bleed occurs before 35 weeks invade delivery is required

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10
Q

What is placenta praevia?

A

Placenta overlies the cervical os

  • Can be complete, partial, marginal or low-lying
  • Partial, marginal and low lying may resolve as pregnancy progresses
  • Associated with vasa praevia where the foetal vessels lie over the internal cervical os
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11
Q

Variants of abnormally adherent placenta

A
  • Placenta accreta: placenta attaches to myometrium instead of being restricted to decidua basalis
  • Placenta increta: where chorionic villi invade into the myometrium
  • Placenta percreta: where chorionic villi invade through the myometrium and sometimes the adjoining tissue
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12
Q

Epidemiology of placenta praevia

A
  • 0/3-0.5% pregnancies worldwide
  • Once c-section increases risk in next pregnancy to 0.6%
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13
Q

Cause of placenta praevia

A
  • Advanced maternal age
  • Multiple pregnancies
  • Smoking
  • Uterine scarring
  • Previous c-section/ uterine scar
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14
Q

Pathophysiology of placenta praevia

A
  • Occurs when blastocyst implants in lower uterine segment near the cervical os
  • Presence of a uterine scar in the lower segment is thought to interfere with the process of placentation
  • Bleeding can occur due to trauma e.g. sex or vaginal examination or as the cervix opens for delivery
  • Untreated haemorrhage due to PP almost always results in death
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15
Q

Classification of placenta praevia

A
  • Complete: placenta covers entire internal cervical os
  • Partial: placenta covers portion of internal cervical os
  • Marginal: edge of placenta lies within 2cm of internal cervical os
  • Low lying placenta: edge of placenta lies within 2-3.5cm of internal cervical os
  • Vasa praevia: foetal vessels overlying cervical os
  • Resolved praevia: low-lying placenta seen in early pregnancy that has migrated away from the os
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16
Q

How is placenta praevia diagnosed?

A
  • Most cases found on USS
  • All patients with previous c-section should have USS at 18 and 20 weeks to check placental location and if PP suspected refer for colour flow doppler USS
  • Painless bleeding in late 2nd or 3rd trimester: take focused hx to exclude risk factors (advanced age, uterine scarring, infertility treatments and previous PP
  • Speculum examination with facilities to convert to immediate c-section
  • Group and save
17
Q

Management of placenta praevia

A

Depends on the degree of bleeding, gestation and if the mother is going into labour

  • Stabilise haemodynamically
  • Continuous foetal heart monitoring as long as bleeding continues
  • Antibiotics if c-section
  • IV access
  • Tranexamic acid (if significant haemorrhage)
  • Blood product and crystalloids
18
Q

Epidemiology of anepartum haemorrhage

A

3-5%

54% due to placenta praevia and abruption

47% unexplained and other

19
Q

What is vasa praevia?

A

Occurs when foetal vessels run in the membranes below the presentin part of the foetus - unsupported by placental tissue or umbilical cord

I: 1:2500 - 1:2700

May present with PV bleeding after ROM followed by rapid foetal distress - classically foetal bradycardia

RFs: low lying placenta, multiple pregnancy, IVF pregnancy, bilobed placenta

30% of pregnancies affected by vasa praevia result in hysterectomy

20
Q

How to differentiate between placnta praevia, vasa praevia and abruption?

A

Abruption = painful

Vasa and placenta praevia = painless

21
Q

Important to know when asking about antepartum haemorrhage

A

Gestational age

Amount of blood

Pain

Date of last smear

Previous PV bleeding

Previous uterine surgery

Drug use/ smoking

Blood ground and Rh status

Obs hx

Placenta position

22
Q

Exclude what before carrying out a V/E in cases of APH?

A

Never perform a V/E before excluding placenta praevia - vasa praevia bleeding generally only occurs following ROM

Once excluded, speculum examination to assess degree of bleeding and possible local causes e.g. trauma, polyps, ectropion and determine if membranes are ruptured

23
Q

Management of placenta praevia

A

Women with PP who have bled previously should be admitted from 34 weeks

Otherwise stay at home as close to hosp as possible

Delivery is likely to be CS if placental edge is <2cm from os