Bleeding in late pregnancy Flashcards
What Hb levels are concerning in pregnancy and postnatal?
<110g/L in 1st-2nd trimester
<105g/L in 3rd trimester
<100g/L postnatal
What physiological adaptations occur in pregnancy?
blood volume increases 50% (but not matched by red cell erythropoiesis –> physiological anaemia)
cardiac output increases 25%
blood pressure decreases (usually)
uteroplacental flow 750ml/min at term
heart rate increases 10-15bpm
Define antepartum haemorrhage
any genital tract bleeding >24 weeks
Causes of antepartum haemorrhage
placenta praevia
placenta abruption
show
cervical pathology
vasa praevia
lower genital tract trauma
Define placental abruption
placenta wholly or partially separates from womb before baby delivered
Placental abruption risk factors
pre-eclampsia
smoking
cocaine use
Consequences of placental abruption for baby
risk of hypoxic injury and growth restriction
What should be initiated after a bleed late in pregnancy?
serial growth scans to monitor growth
Signs of placental abruption
painful antepartum haemorrhage
woody hard uterus due to uterus filling with blood (some will leave through cervix but not all)
How does placenta praevia present?
painless bleeding
What is placenta praevia?
placenta attaches inside the uterus but in a position near or over the cervical opening
not usually a problem when cervix closed
What advice should be given to women with placenta praevia?
refrain from intercourse
absolute indication for caesarean section around 36 weeks to decrease risk of spontaneous labour
Presentation of vasa praevia
painless bleeding after rupture of membranes
What is vasa praevia?
unprotected fetal blood vessels cross or run near the cervix
cord inserts into amniotic membrane rather than directly into placenta
(not a problem if free vessels elsewhere in uterus, only problem if overlie cervix)
Vasa praevia management
if bleed occurred, deliver ASAP
baby can exsanguinate within minutes
4Ts of postpartum haemorrhage
tone
traum:
- tears
- uterine extensions at caesarean birth
- treatment via surgical repair
tissue:
- retained products of conception
- uterine evacuation/antibiotics
thrombin:
- DIC/coagulatory abnormalities
- correction
What is poor tone of the uterus?
failure of uterus to contract back down after birth
Risk factors for atony of uterus causing post-partum haemorrhage
uterine over-distension: large for gestational age, polyhydramnios, multiple
prolonged labour
obesity
induction of labour
instrumental delivery/caesarean section
general anaesthetic
multiparity
Post-partum haemorrhage treatment
bimanual compression
uterotonic medication:
- oxytocin
- ergometrine
- carboprost, misoprostol (prostaglandins)
tranexamic acid
surgical/mechanical approaches:
- B-Lynch/brace suture
- balloon tamponade
- hysterectomy
What is placenta accreta?
normally in women with previous C-section, placenta grows too deeply into uterine wall
needs caesarean-hysterectomy as cannot remove placenta
(will not cause antepartum haemorrhage but can bleed intra-operatively)
