Obstetric haemorrhage Flashcards
(33 cards)
How common is obstetric haemorrhage?
Major cause of maternal death worldwide (up to 50% of cases). In UK, deaths are rare.
What are the categories of obstetric haemorrhage?
Vaginal bleeding associated with IUP is divided into 4 categories:
- Threatened miscarriage (up to 24 weeks)
- Antepartum haemorrhage (24 weeks > onset of labour)
- Intrapartum haemorrhage (onset of labour end of 2nd stage)
- Post-partum haemorrhage (3rd stage > end of puerperium / 6 weeks post-delivery)
What is Antepartum Haemorrhage?
Bleeding from the genital tract or into the genital tract after 24+0 weeks of pregnancy.
- Incidence 3-5% of pregnancies
- Classified according to source of bleeding (local or placental)
- Is this arbitrary cut-off still valid? What about women 23+ - threatened miscarriage?
Causes
• MOST APH = unexplained.
• Important: Placental abruption (pain & bleeding), placenta prævia (painless)
• Other: Vasa praevia, cancer, previous trauma (including sexual assault).
Local causes of APH?
Not clinically important
• Cervical bleeding not uncommon, may follow sexual intercourse
o Cervical ectropion or benign polyp may be found
o Very rarely: cervical carcinoma
• Blood-stained ‘show’ (late in pregnancy, mucus with small amount of blood – onset of labour when cervix becomes effaced)
• Other local causes (lower genital tract / vulval).
What is placental abruption?
Retroplacental haemorrhage (between placenta + uterus), usually involves some degree of placental separation.
Predisposes to fetal hypoxia / acidosis.
Symptoms: bleeding & PAIN e.g. abdominal pain over uterus; especially in concealed abruption > hard uterus.
Concealed abruption = retroplacental bleeding without any external loss! *amount of PV bleeding (‘revealed’ blood) may not reflect total blood loss!
1 = partial separation (concealed haemorrhage)
2 = partial separation (apparent haemorrhage)
3 = complete separation (concealed haemorrhage)
Risk factors for placental abruption?
- Abruption affecting previous pregnancy (most predictive risk factor)
- Pre-eclampsia
- Fetal growth restriction
- Malpresentation
- Polyhydramnios
- Advanced maternal age >40
- Multiparity
- Low BMI
- IVF
- Chorioamnionitis
- Premature rupture of membranes
- Smoking, cocaine, amphetamines
Management of placental abruption?
Light bleeding from edge of normally situated placenta (does not usually compromise fetus): brief inpatient observation & subsequent growth surveillance (serial USS fetal biometry) until delivery at term
2. Major revealed haemorrhage: urgent delivery
3. Major concealed haemorrhage (pain, uterine tenderness, hypovolaemic shock): urgent delivery, vaginal vs LSCS depends on degree of bleeding and maternal & fetal conditions
• If no fetal heartbeat: vaginal delivery preferred
• However, likely there has been major blood loss, hypovolaemic shock may develop & progress to multisystem failure if not corrected.
• Thromboplastins from damaged placenta may also lead to disseminated intravascular coagulation [DIC]: ↓ platelets, fibrinogen & other clotting factors
• Therefore, C-section may occasionally be indicated to minimise systemic maternal risks (operating in presence of DIC also carries risk!)
Less severe degrees of abruption still associated with fetal compromise (retroplacental clot irritation of myometrium pain & frequent contractions abnormal pattern on FH deterioration to fetal bradycardia & death) unless delivery expedited.
Placental abruption predisposes mother to postpartum haemorrhage
“Abruption kills the baby but post-partum haemorrhage kills the mother”
What is placenta praevia?
Placenta attached in the lower uterine segment (i.e. 5cm from internal os). Identified by the uterovesico fold of peritoneum. If bleeding: typically fresh red blood. More common if previous C-section but majority have no identifiable risk factors!
Type I: encroaches on lower segment
Type II: reaches internal os (marginal)
Type III: covers part of os (partial)
Type IV: completely covers the os (complete)
Difference between minor and major placenta praevia?
Minor placenta praevia (type I + II)
• Lower risk of complications
• May deliver vaginally if >2cm from os
• If <2cm from os: C-section
Major placenta praevia (type III + IV)
• High risk of complications
• C-section
Management of placenta praevia?
Suitability for delivery: transvaginal USS to measure distance from internal os & engagement of presenting part (if not at least partially engaged – should have Caesarean).
Some clinicians advise admission from 30-32 weeks: facilities for resuscitation & delivery readily available - immobility in hospital may predispose VTE. Outpatient management common, particularly if incidental finding with no bleeding / only light bleeding & live close to hospital. Elective delivery usually planned for 38-39 weeks (but will be earlier if there is major haemorrhage). C-section should be supervised / performed by senior obstetrician as large blood loss is common (due to poor capacity of lower segment of uterus to contract).
Diagnosis of placenta praevia? When is it seen?
Placental location routinely determined at 20 week anomaly scan. Uterus grows from lower segment upwards ∴ placenta appears to move upwards with advancing gestation (this is simply a feature of uterine growth, does not reflect migration of the placenta). If identified: repeat scan in early in 3rd trimester then review management.
Placenta praevia at term is seen in:
• 2% of those with low-lying placenta <24 weeks
• 5% of those with low-lying placenta at 24-29 weeks
• 23% of those with low-lying placenta at 30+ weeks
How is APH assessed?
Usually women with vaginal bleeding in pregnancy are well, however, our population are young, fit and usually healthy with large circulating blood volumes- can tolerate large blood losses (?>1.5 litres) with no symptoms at all
If patient is compromised:
• Airway (patent or not)
• Breathing (respiratory distress or not – give O2)
• Circulation (pulse, BP, estimation of blood loss, capillary refill, 2x venflons, IV crystalloid)
• Disability (AVPU)
• Exposure (examine the abdomen and a gentle speculum examination)
• Once the patient is stable, assess fetal wellbeing
• Delivery should only be contemplated once maternal condition is stable
If patient is not compromised
• Take a history: pain? contractions? bleeding: quantity? post-coital? recurrent?
• Look at the 20 week scan: placental site assessment
• Examine: very tender / hard (like wood), suggests significant abruption (ABCDE etc). Speculum; may be able to diagnose ectropion: DON’T miss cancer in women with recurrent bleeding
• Fetal assessment: CTG abnormal > immediate delivery IF patient unstable
What is placenta accreta?
In a small proportion of placenta praevia > morbidly adherent placenta. Affects women with anterior placenta praevia and previous history of surgery (especially Caesarean section[s]).
Placenta Accreta: chorionic villi of placenta attach to myometrium & placenta cannot be readily separated from the uterus following delivery. Can be diagnosed with USS antenatally & MRI increasingly used to improve accuracy. Markedly increases chance of severe haemorrhage: multi-disciplinary approach to delivery recommended. Severe haemorrhage can require hysterectomy – should warn women prior to surgery.
What is placenta increta? Placenta percreta?
Placenta increta: chorionic villi of placenta invade into myometrium
Placenta percreta: chorionic villi of placenta invade through the perimetrium (uterine serosa). Highest-risk form of the condition – can lead to placenta attaching to other organs e.g. rectum or urinary bladder
Note: can still get increta / percreta without placenta praevia if placenta not in lower segment.
What are the degrees of APH?
Degrees of haemorrhage • Spotting: can almost always go home • Minor (<50ml); home if well • Major 1 (50-500ml), admit, deliver • Major 2 (500-1000ml): admit, resuscitate, deliver
Massive (>1000ml), with/without signs of shock, signs of shock alone (concealed abruption): immediate resuscitation & delivery once patient fit for general anaesthesia (VERY rare to need to operate on unstable patient).
What are complications of APH?
- Maternal: anaemia, shock, renal failure, DIC, postpartum haemorrhage, blood transfusion, hysterectomy (rare), psychological effects
- Fetal: acute fetal distress, anaemia, fetal death, fetal growth restriction, prematurity (iatrogenic and pathological)
Other issues: corticosteroids if delivery expected and <35 weeks, rhesus disease prophylaxis (anti-D), neonatologists present at delivery, blood cross matched in major APH, ? hysterectomy in placenta accreta, counselling postnatally / planning for the next pregnancy
What is intrapartum haemorrhage?
Placental abruption can also occur during labour: particularly considered if the uterus does relax between contractions
Placenta praevia can cause painless bleeding during labour, as the cervix dilates the placenta separates from the uterine wall.
Vasa Praevia
What is vasa praevia?
Rare condition: umbilical cord vessels run in fetal membranes near the cervix (cross internal os). May rupture intrapartum (often in early labour) –>
fetal demise / severe neonatal anaemia. Presents as severe fetal distress / death following relatively small intrapartum haemorrhage.
Type I: cord inserted into membranes (rather than directly into placenta)
Type II: vessels run from placenta to a separate succenturiate placenta lobe.
Tests to differentiate fetal & maternal blood unreliable (haemoglobin F in textbooks but realistically don’t have time -> clinical diagnosis): usually urgent Caesarean section due to fetal compromise.
Diagnosis typically retrospective (examination of placenta & membranes): possible to diagnose antenatally with colour flow Doppler, not routinely screened.
What is postpartum haemorrhage?
Primary PPH: loss of 500ml within 24 hours of the birth
• Minor: 500-1000ml
• Moderate: 1000-2000ml
• Major >2000ml
Secondary PPH: abnormal or excessive bleeding from birth canal from 24 hours - 12 weeks postnatally
How common is PPH?
Daily: 216 women die from obstetric haemorrhage; most are preventable.
In the UK…
• affected 13% of all maternities in England (2011-2012).
• Incidence increasing: diabetes, age
• Significant cause of maternal morbidity
• Obstetric haemorrhage accounts for approximately 10% of all direct maternal deaths
• PPH = 2nd leading cause of direct maternal death in UK
Risk factors for PPH?
The 4 Ts: Tone, Trauma, Tissue, Thrombin
Tone: Placenta praevia, Multiple pregnancy, Previous PPH, Asian ethnicity, BMI >35, Gestational diabetes, Anaemia (independent risk factor: less resistant but also creates PPH risk in 1st place)
Trauma: Em LSCS (OR: 4), El LSCS (OR: 2), Mediolateral
Episiotomy, Operative vaginal delivery
Tissue: Retained placenta- includes membranes, clots
Thrombin: Abruption, Pre-eclampsia, Pregnancy-induced hypertension, Pyrexia in labour
Pre-existing conditions: clotting, PET
Primary vs secondary PPH - Risk factors?
Primary: ocurs in around 5% of all deliveries: more common in grand multiparity (≥4 deliveries), age >35, BMI >35, multiple pregnancy, fibroids, polyhydramnios, placenta praevia, long labour, previous history PPH. It may also follow an antepartum haemorrhage.
Secondary PPH usually due to infection of uterine cavity, retained PoC or both (occasionally caused by trophoblastic disease). Measure obs & palpate uterus for tenderness > culture endocervical & vaginal swabs.
Endometritis most common cause of secondary PPH
Main causes of primary PPH?
- Atony (90%)
Normally, contraction in 3rd stage causes compression of intramyometrial blood vessels which stops bleeding quickly. If atony, compression does not occur. May follow delivery of entire placenta (myometrium simply does not contract sufficiently) or when part / whole placenta is retained (physical tissue prevents effective contraction and the partial placental separation –> bleeding from placental bed). - Trauma (7%)
Bleeding may originate from episiotomy, vaginal tear, cervical laceration or rupture in uterine wall (lacerations of genital tract more common post instrumental delivery) - Coagulation problems
Usually DIC: may exist due to numerous causes including maternal sepsis, placental abruption - Multiple causes
Systematic approach required
How can PPH be prevented?
Reducing incidence of PPH • Recognition of risk factors • Treat antenatal anaemia (haematinic supplements) • Active management of 3rd stage • MDT planning for placenta accreta
Active management of 3rd stage
- Oxytocin or Syntometrine
- Controlled cord traction (hold uterus to check if placenta coming out; beware of uterine inversion: acute obstetric emergency, can accelerate PPH –> massive vasovagal episode (profound bradycardia —> cardiac arrest).
