Antepartum haemorrhage Flashcards
What are the common and rarer causes of antepartum haemorrhage?
Common:
Undetermined origin
Placental abruption
Placenta praevia
Rare:
Vasa praevia
Uterine rupture
Incidental genital tract pathology - cervical carcinoma in overdue smear.
What is placenta praevia?
When the placenta is implanted in the lower segment of the uterus.
Why are only 1 in 10 low lying placentas actually praevia at term?
Because the placenta implants in the myometrium and this moves away from the internal cervical os. The low lying placentas therefore look like they move upwards as pregnancy continues .
What are marginal and major placenta praevia?
Marginal = placenta in lower segment, not over os. Major = placenta completely or partially covering os.
In which situations is placenta praevia more common?
In twins
Advancing maternal age
Advancing parity
Uterine scarring
What are the major complications of placenta praevia?
Abnormal lie and lack of head engagement in major placenta praevia –> caesarian section is required.
Can cause severe haemorrhage postpartum as the lower uterus is not able to contract as well to constrict the maternal blood vessels.
If the placenta also implants in a previous c-section scar, it may develop so deep that it prevents placental separation (placenta accreta) - this may provoke massive haemorrhage and often requires hysterectomy.
What is suggested by NICE about vaginal examination on a pregnant woman with vaginal bleeding?
Never perform a vaginal examination on a woman with vaginal bleeding unless placenta praevia has been excluded.
What are the presentations of placenta praevia?
Found on ultrasound Vaginal bleeding (mild) before delivery Abnormal lie/breech presentation (seen in major subtype)
What investigation is used to make the diagnosis of placenta praevia?
Ultrasound
After discovery of placenta praevia, what is done?
Ultrasound is repeated at 32 weeks. This is done vaginally if the placenta is posterior.
How close to the internal os does a low-lying placenta need to be to make it likely to be placenta praevia at term?
<2cm.
If the placenta is anterior and the mother has had a previous caesarian section, what is done?
3D power ultrasound is performed to determine if there is a placenta accreta and how severe it is. MRI is also useful.
When presentation of placenta praevia is with bleeding, what needs to be done to assess wellbeing of mother and foetus?
Cardiotocography (TCG)
FBC
Clotting studies
Cross match
When is delivery for a pregnancy with a placenta praevia which is asymptomatic? What about symptomatic?
Asymptomatic: 39 weeks by caesarian section
Symptomatic: delivery. Blood is kept available, steroids administered if gestation < 34 weeks, anti-D to Rhesus negative women.
What is a common consequence after delivery of a baby with placenta praevia?
Intraoperative and postpartum haemorrhage. Common because the lower segment of the uterus doesn’t contract well after delivery, or because the placenta is accreta.
What is the treatment for placenta accreta?
Compression of the inside of the scar after removal of the placenta with an inflatable balloon, excision of the affected uterine segment or, frequently, hysterectomy.
What is placental abruption?
When all or part of the placenta separates before delivery of the foetus.
When placental abruption occurs, what are the different consequences?
Further placental separation and acute foetal distress may follow.
Antepartum haemorrhage may follow if the blood tracts down between the membranes and myometrium.
Blood may pass into the myometrium with no APH (20%) and so visible haemorrhage is absent.
What are the main risk factors for placental abruption?
IUGR Pre-eclampsia Pre-existing hypertension Maternal smoking Previous placental abruption
What are the possible consequences of placental abruption?
Foetal death (30%) Maternal death if SIDs, renal failure and blood transfusion needed all occur.
How do revealed and hidden uterine abruptions present?
Revealed - painful bleeding, tender uterus (note that the bleeding does not correspond to the severity). Pain is due to the blood behind the placenta and in the myometrium.
Hidden - pain (tender uterus).
Both - tachycardia, hypotension in massive blood loss. Uterus is tender and often contracting. Labour follows.
What are the features of a major placental abruption?
Maternal collapse Coagulopathy Foetal demise/distress Woody hard uterus Poor urine output or renal failure.
What is the management of a placental abruption?
Admission
Foetal monitoring = CTG
Maternal monitoring = FBC, fluid balance, renal function, clotting.
Steroids if <34 weeks
Opioids
Anti-D if required
Delivery or conservative management:
- Foetal distress = caesarian section
- No foetal distress and gestation > 37 week = induction of labour with amniotomy. If foetal distress ensures, c-section is performed.
- If the foetus is dead = blood products given (coagulopathy is likely), labour is induced.
No foetal distress and <37 weeks and degree of abruption is minor –> if symptoms settle they can be discharged.
What is amniotomy?
Artificial rupture of membranes
What is vasa praevia?
Occurs when a foetal blood vessel runs in the membranes in front of the presenting part. These vessels usually result from the umbilical cord being attached to the membranes rather than the placenta or when the placenta is in parts.
What are the signs/symptoms of ruptured vasa praevia and what are the consequences?
Rupture usually occurs when membranes rupture and is more likely in vessels closer to the cervix (e.g. praevia).
Often presents as painless, moderate bleeding at the rupture of the membranes.
Massive foetal bleeding ensues, severe foetal distress and often C-section is not quick enough to save the foetus.
