Obstetrics

Placental Abruption

Premature separation of a normally sited placenta: decidual bleeding strips the placenta off the uterine wall, so pain, hypertonus, fetal hypoxia and coagulopathy appear with almost no visible blood.

In a nutshell

Placental abruption is premature separation of a normally sited placenta, and the visible bleeding badly understates the true loss. Resuscitate, activate the major obstetric haemorrhage protocol at over 1000 mL or clinical shock, keep fibrinogen above 1.5 g/L, and expedite birth.

Classic presentation

A woman at 34 weeks with pre-eclampsia has sudden constant abdominal pain, a woody tender uterus, minimal vaginal bleeding, tachycardia and an abnormal cardiotocograph (CTG).

Key points

About 70% of abruptions happen in low-risk pregnancies, so an absence of risk factors is not reassurance.
Recurrence is 4.4% after one previous abruption and 19% to 25% after two, which makes the next pregnancy consultant-led with serial growth scans.
Tocolysis is contraindicated in abruption and must not be used in major antepartum haemorrhage or haemodynamic instability.
The Kleihauer test quantifies fetomaternal haemorrhage to size the anti-D dose. It is not a test for abruption.
There is no separate Green-top guideline for abruption: it sits inside Green-top Guideline No. 63, a first edition last reviewed in December 2011.
Continuous pain suggests abruption; intermittent pain suggests labour. A woody uterus means significant abruption; a soft one points to praevia.
Coagulopathy and cardiovascular instability are specific contraindications to regional anaesthesia, so these women often need a general anaesthetic.

First-line investigation

It is a clinical diagnosis: airway, breathing, circulation, disability and exposure (ABCDE) plus continuous cardiotocography (CTG), then FBC, coagulation screen with fibrinogen, group and crossmatch. Ultrasound only excludes praevia; its sensitivity for abruption is 24%.

Management

Resuscitate and call the team

ABCDE. Oxygen 10 to 15 litres/minute by facemask, two 14-gauge cannulae, left lateral tilt, keep her warm. Take 20 mL of blood and crossmatch 4 units.¹
Until blood arrives give up to 2 litres of warmed Hartmann's solution and 1 to 2 litres of colloid, to a maximum of 3.5 litres.¹
Trigger the major obstetric haemorrhage protocol at over 1000 mL and/or clinical shock. Call consultant obstetrician, anaesthetist and haematologist; alert transfusion.^1,3
Stabilise the mother before establishing the fetal condition. She is the priority when both patients are compromised.¹

Assess both patients

Continuous cardiotocography once she is stable. It is abnormal in about 69% of abruptions, so a normal trace does not exclude one.^1,3
Ultrasound excludes placenta praevia and confirms fetal heart activity. Sensitivity for retroplacental clot is only 24%, so it cannot rule abruption out.¹
Send FBC, coagulation screen with fibrinogen, U&E, group and antibody screen. Repeat through the bleed: a normal early screen does not reassure.^1,2
Falling platelets mark consumption. An acutely bleeding woman can have a normal haemoglobin, and the first value does not reflect the volume lost.^1,2

Correct the coagulopathy to target

Fresh frozen plasma (FFP) 12 to 15 mL/kg, about 4 units or 1 litre, for every 6 units of red cells, then guided by clotting results.²
Cryoprecipitate two 5-unit pools early, then guided by fibrinogen results, aiming to keep fibrinogen above 1.5 g/L.²
Keep platelets above 50 × 10⁹/L while she is bleeding; the transfusion trigger is 75 × 10⁹/L.²
Red cells are almost always needed below a haemoglobin of 60 g/L and rarely needed above 100 g/L. No firm criteria exist.²
In continuing massive haemorrhage, up to 4 units of FFP and 10 units of cryoprecipitate may be given empirically while awaiting results.¹
Fibrinogen concentrate is not licensed in the UK for acquired bleeding, so cryoprecipitate is the fibrinogen source. Involve haematology early.²

Anti-D, steroids and what not to give

Anti-D at least 500 units by deep intramuscular injection within 72 hours after any antepartum haemorrhage, even if routine antenatal prophylaxis was already given.^1,4
Kleihauer after 20+0 weeks: add 100 to 125 units per mL of fetal red cells if fetomaternal haemorrhage exceeds 4 mL. Before 20+0 weeks, 250 units.^1,4
For recurrent bleeding after 20+0 weeks in a non-sensitised rhesus D (RhD)-negative woman, repeat anti-D at minimum 6-weekly intervals.¹
Offer maternal corticosteroids at 24+0 to 33+6 weeks and consider them at 34+0 to 35+6 weeks. Never delay a birth needed for compromise.^5,1
No tocolysis: it is contraindicated in abruption, in major antepartum haemorrhage, in instability and where the fetus is compromised.¹

Deliver, then protect the third stage

Live fetus with compromise: caesarean birth with concurrent resuscitation. Major abruption is a category 1 caesarean, within 30 minutes of the decision.⁶
Fetal death with a satisfactory maternal condition: vaginal birth is the recommended mode for most women.¹
Coagulopathy and cardiovascular instability contraindicate regional anaesthesia. Deliver in a unit with on-site blood transfusion services.^1,6
Anticipate postpartum haemorrhage: active third stage, and consider ergometrine with oxytocin 1 mL intramuscularly after delivery unless she is hypertensive.^1,7

Afterwards

Restart thromboprophylaxis once the haemorrhage risk falls. Haemorrhage and transfusion are themselves venous thromboembolism risk factors.¹
Debrief with an experienced obstetrician, offer follow-up at 4 to 6 weeks, and report through clinical incident systems.¹
Reclassify the pregnancy as high risk and consultant-led, with serial ultrasound for fetal growth.¹

Exam traps

Do not judge severity by the pad. Fetal compromise or fetal death signals maternal volume depletion, not just fetal risk.
Antepartum 'major' haemorrhage is 50 to 1000 mL without shock. Postpartum 'major' is over 1000 mL. The terms are not interchangeable.
A normal ultrasound does not exclude abruption: it misses three-quarters of them. A positive scan, though, is close to diagnostic.
Pregnancy raises fibrinogen to 3.5 to 6.5 g/L, so a 'normal-looking' 2 g/L in a bleeding woman is abnormally low.
Do not give ergometrine with oxytocin to a hypertensive or pre-eclamptic woman, even though abruption and pre-eclampsia travel together.
A normal early clotting screen does not reassure. Repeat FBC and coagulation, including fibrinogen, throughout the bleeding episode.
Do not delay a birth that is needed. Antepartum haemorrhage with maternal or fetal compromise requires immediate delivery, steroids or not.

Illustrations

Retroplacental haematoma: the clot that was never seen at the introitusGross pathology specimen of a delivered placenta with adherent retroplacental clot, showing the volume of blood that can sit behind the placenta while little or nothing appears vaginally.Mikael Häggström, Wikimedia Commons · CC0

Key sources

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.