Postpartum Hemorrhage & Obstetric Emergencies

Haemorrhage is the leading direct cause of maternal death in India, and almost every death from it is preventable.

The organising tool is that in obstetric haemorrhage the uterus is both the source and the solution. An empty, contracted uterus does not bleed.

At term the uterus receives around 600 to 800 millilitres of blood every minute, which is roughly a fifth of the cardiac output. Haemostasis after delivery is not primarily achieved by clotting. It is achieved mechanically, by the interlacing myometrial fibres contracting around the spiral arteries and occluding them, which is why they are called the living ligatures.

That single fact explains the whole subject. If the uterus does not contract, no amount of clotting factor will stop the bleeding, which is why atony causes catastrophic loss in minutes and why every first-line treatment is aimed at making the uterus contract.

It also explains the diagnostic sequence. When a woman bleeds after delivery, the questions are whether the uterus is contracted, whether it is empty, whether the tract is intact and whether the blood will clot.

1. The Four T's

The causes of postpartum haemorrhage are conventionally grouped as tone, trauma, tissue and thrombin, and the grouping is genuinely useful because it is ordered by frequency.

Atony dominates so heavily that it should be assumed until excluded, and the risk factors are anything that overstretches the uterus or exhausts it: multiple pregnancy, polyhydramnios, macrosomia, high parity, prolonged or augmented labour, chorioamnionitis and retained products.

Trauma is suggested when the uterus is well contracted and the woman is still bleeding, which is the single most useful discriminator at the bedside.

Thrombin is rarely the primary cause but is frequently a secondary one, because massive transfusion, hypothermia and consumption all produce coagulopathy, and abruption and amniotic fluid embolism cause it directly.

2. Prevention and What Changed

Active management of the third stage reduces postpartum haemorrhage substantially and is standard practice. It comprises a prophylactic uterotonic, controlled cord traction and uterine massage.

Oxytocin is the uterotonic of choice, given immediately after delivery of the baby. Heat-stable carbetocin is a useful alternative where the cold chain cannot be maintained, which matters in much of India.

The most important recent development is the E-MOTIVE trial, which changed practice by attacking detection rather than treatment.

It combined a calibrated blood-collection drape for objective early detection with an immediate bundle of uterine massage, oxytocics, tranexamic acid, intravenous fluids, examination and escalation, delivered together rather than sequentially.

The result was a roughly 60 per cent relative reduction in the composite of severe haemorrhage, laparotomy for bleeding and death from bleeding, across more than 200,000 women.

The reason it worked is instructive: the interventions were not new. What was new was measuring blood loss objectively instead of estimating it, and giving all the treatments at once rather than escalating one at a time while the woman continued to bleed.

3. Why Estimation Fails

Postpartum haemorrhage is defined as blood loss of 500 millilitres or more after vaginal delivery, or 1,000 millilitres or more after caesarean section, though any loss causing haemodynamic compromise qualifies.

Visual estimation of blood loss is unreliable and systematically underestimates large volumes, which is precisely why a calibrated drape improves outcomes.

The physiology compounds the problem. Plasma volume rises by around 40 to 50 per cent in pregnancy, so a healthy woman can lose a great deal of blood before her blood pressure falls.

Tachycardia and a narrowed pulse pressure precede hypotension, exactly as in trauma, and hypotension in an obstetric haemorrhage is a late and ominous sign.

An anaemic woman has no such reserve, which is why the same volume of blood loss kills in India that would be survived elsewhere, and why anaemia correction is part of haemorrhage prevention.

The shock index, the heart rate divided by the systolic blood pressure, is a useful bedside measure because it rises before either number alone becomes alarming.

4. Managing Postpartum Haemorrhage

Management is simultaneous rather than sequential: call for help, resuscitate, find the cause and treat it, all at once.

Resuscitation is two large-bore cannulae, blood samples including cross-match, fluid and early blood products, and a massive transfusion protocol if loss continues.

Uterine massage and bimanual compression are performed immediately while drugs are drawn up, because mechanical compression works instantly and drugs take minutes.

The uterotonics are used in sequence, and their contraindications are examined more often than their doses.

Ergometrine in a pre-eclamptic woman and carboprost in an asthmatic are the two errors the examination tests.

Tranexamic acid is given as early as possible and within three hours of onset, because it reduces death from bleeding and, as with trauma, later administration is not merely ineffective.

If bleeding continues, mechanical and surgical measures follow: intrauterine balloon tamponade, compression sutures such as the B-Lynch, stepwise devascularisation by ligating the uterine and then internal iliac arteries, and uterine artery embolisation where available.

Hysterectomy is the final step and must not be delayed too long, because the commonest contributor to death is persisting with conservative measures in a woman who is already coagulopathic.

Non-pneumatic anti-shock garments are useful for stabilising a woman during transfer in low-resource settings.

Aortic compression buys time when nothing else is available. Pressing the closed fist firmly downwards just above the umbilicus compresses the abdominal aorta against the vertebral column, reducing uterine arterial inflow, and it can be sustained by an assistant while the theatre is prepared.

Its value is that it requires no equipment and no drug, which is precisely why it belongs in the repertoire of anyone working where both may be unavailable.

5. Secondary Postpartum Haemorrhage

Secondary haemorrhage occurs between 24 hours and 12 weeks after delivery, and the two causes are retained products of conception and endometritis, often together.

Presentation is bleeding with an offensive discharge, fever, uterine tenderness and a subinvoluted uterus.

Management is antibiotics with evacuation where products are retained, and evacuation of an infected uterus carries a real risk of perforation, so it is performed carefully and after antibiotics have been started.

6. Antepartum Haemorrhage

Antepartum haemorrhage is bleeding after 24 weeks and before delivery, and two conditions dominate.

Placenta praevia is painless bleeding from a placenta lying in the lower segment. The uterus is soft and non-tender, the fetal condition is usually good, and malpresentation is common because the placenta occupies the lower segment.

Placental abruption is painful bleeding from premature separation of a normally sited placenta. The uterus is tense, tender and irritable, the fetal condition is often poor, and the visible bleeding may be far less than the actual loss because blood is concealed behind the placenta.

That concealed loss is the trap. A woman may be in profound shock with modest visible bleeding, and the degree of shock should be judged against her physiology rather than against what is on the sheet.

Vaginal examination is contraindicated in suspected placenta praevia until the placental site is known, because a digital examination can provoke torrential haemorrhage. Ultrasound is performed first.

Abruption is associated with hypertension and pre-eclampsia, trauma, smoking, cocaine use, previous abruption and sudden uterine decompression. It causes disseminated intravascular coagulation more often than any other obstetric condition, through release of thromboplastin from the damaged placenta.

Vasa praevia is rare but distinctive: painless bleeding at membrane rupture with rapid fetal deterioration, because the blood lost is fetal rather than maternal, and a fetus has very little to lose.

7. The Placenta Accreta Spectrum

Placenta accreta means abnormal adherence of the placenta to the myometrium because of a deficient decidua, and it exists on a spectrum with increta invading the myometrium and percreta penetrating the serosa.

The risk factors are previous caesarean section and placenta praevia, and the two multiply. A woman with a praevia overlying a previous caesarean scar is at very high risk, because the scar has no decidua for the placenta to stop at.

Its incidence is rising directly in proportion to caesarean section rates, which makes it a self-inflicted epidemic.

Antenatal diagnosis by ultrasound and magnetic resonance imaging is what makes the difference, because it allows delivery to be planned at a centre with blood, surgical expertise and intensive care.

Attempting to remove an accreta placenta causes catastrophic haemorrhage, so management is planned caesarean hysterectomy or leaving the placenta in situ in selected cases.

8. Other Obstetric Emergencies

Uterine rupture presents with scar tenderness, an abnormal fetal heart pattern which is often the earliest sign, cessation of contractions, loss of station and maternal collapse. It requires immediate laparotomy.

Uterine inversion follows traction on an unseparated placenta and causes profound shock, often disproportionate to the blood loss because of vagal stimulation. The uterus is replaced immediately, before the cervical ring contracts, and the placenta is removed only after replacement.

Amniotic fluid embolism is rare, unpredictable and often fatal. It presents with sudden cardiovascular collapse, hypoxia and disseminated intravascular coagulation, classically during labour or immediately after delivery. It is a diagnosis of exclusion and management is entirely supportive.

Cord prolapse is an emergency because the cord is compressed between the presenting part and the pelvis. The presenting part is elevated manually, the woman is placed knee-chest or in steep head-down tilt, the bladder may be filled, and delivery is expedited, usually by caesarean section.

Handling the cord is minimised because it causes vasospasm.

9. Puerperal Sepsis and Thromboembolism

Sepsis remains a direct cause of maternal death, and its danger lies in how well young women compensate.

Puerperal sepsis is genital tract infection at any time between the rupture of membranes and 42 days postpartum. The uterus after delivery is an ideal culture medium: a large raw placental bed, retained blood, and a cervix that is still open.

Risk factors are prolonged rupture of membranes, repeated vaginal examinations, prolonged labour, caesarean section, retained products and pre-existing anaemia.

Presentation is fever, offensive lochia, uterine tenderness, subinvolution and abdominal pain. Group A Streptococcus deserves particular fear, because it can progress from mild symptoms to fulminant septic shock within hours.

Management follows the source control principle: broad-spectrum antibiotics started immediately after cultures, and evacuation of retained products or drainage of collections, because antibiotics alone will not sterilise an undrained focus.

The obstetric trap is that the physiological tachycardia and relative hypotension of pregnancy make the early signs of sepsis look normal, so deterioration is recognised late.

Venous thromboembolism is the leading direct cause of maternal death in many high-income settings and is rising in India as caesarean rates rise.

Pregnancy is prothrombotic by design, satisfying every element of Virchow triad: clotting factors rise while protein S falls, venous stasis increases as the uterus compresses the pelvic veins, and delivery injures the vessel wall.

Risk is highest in the puerperium rather than during pregnancy, and left leg deep vein thrombosis predominates because the right common iliac artery crosses and compresses the left common iliac vein.

Low molecular weight heparin is the treatment and prophylaxis of choice, because it does not cross the placenta. Warfarin is teratogenic and is avoided, particularly in the first trimester.

10. Ectopic Pregnancy

Ectopic pregnancy is implantation outside the uterine cavity, most often in the ampulla of the fallopian tube, and it remains a cause of maternal death in early pregnancy.

Risk factors are anything damaging the tube: previous pelvic inflammatory disease, genital tuberculosis, previous ectopic pregnancy, tubal surgery, and pregnancy with an intrauterine device in place.

The classical triad is amenorrhoea, abdominal pain and vaginal bleeding, but the presentation is frequently atypical, and the crucial rule is that any woman of reproductive age with abdominal pain must have a pregnancy test.

Diagnosis uses transvaginal ultrasound with serum human chorionic gonadotropin. In a normal early pregnancy the level roughly doubles every 48 hours, and a suboptimal rise suggests an abnormal pregnancy.

An empty uterus with a level above the discriminatory zone suggests ectopic pregnancy, because an intrauterine pregnancy should be visible at that level.

Management is expectant in selected resolving cases, medical with methotrexate where the woman is stable with a small unruptured ectopic and a low hormone level, and surgical where she is unstable, the ectopic is large or ruptured, or medical treatment fails.

A ruptured ectopic causing haemodynamic instability is a surgical emergency, and resuscitation and surgery proceed together.

11. Worked Examples

Example 1. A woman bleeds heavily after a prolonged augmented labour with twins. The uterus is soft and boggy.

Tone accounts for 70 to 80 per cent of postpartum haemorrhage, and every risk factor here points to it: twins overdistended the uterus, and prolonged augmented labour exhausted it.

Bimanual compression and massage begin immediately while uterotonics are prepared, because mechanical compression acts instantly. Oxytocin is first line, tranexamic acid is given within three hours, and resuscitation runs in parallel. A soft boggy uterus is the definition of atony.

Example 2. A pre-eclamptic woman has postpartum haemorrhage. Oxytocin has failed and a colleague suggests ergometrine.

Ergometrine causes generalised smooth muscle constriction including vascular smooth muscle, so it raises blood pressure and is contraindicated in hypertension and pre-eclampsia, where it risks stroke.

Carboprost is the appropriate second-line agent unless she is asthmatic, and misoprostol is an alternative. Mechanical measures continue throughout, and tranexamic acid is given if not already.

Example 3. A woman at 32 weeks with pre-eclampsia has continuous abdominal pain and a tense tender uterus, with only modest vaginal bleeding but a pulse of 130 and a systolic pressure of 88.

This is placental abruption, and the modest visible bleeding is the trap. Blood is concealed behind the placenta, so the visible loss bears no relation to the actual loss, and her tachycardia and hypotension indicate substantial haemorrhage.

Resuscitation with blood, delivery, and anticipation of disseminated intravascular coagulation are required, since abruption causes it more often than any other obstetric condition through thromboplastin release. Pre-eclampsia is a recognised risk factor.

Summary

• The uterus is both source and solution; an empty contracted uterus does not bleed.
• Myometrial fibres are the living ligatures occluding the spiral arteries.
• The uterus receives about a fifth of cardiac output at term.
• Tone causes 70 to 80 per cent of postpartum haemorrhage.
• A contracted uterus with continued bleeding means trauma.
• Active management uses a uterotonic, cord traction and massage.
• Heat-stable carbetocin is useful where the cold chain fails.
• The E-MOTIVE bundle cut severe outcomes by around 60 per cent.
• It worked by objective detection and simultaneous rather than sequential treatment.
• Visual estimation systematically underestimates large blood loss.
• Plasma volume rises 40 to 50 per cent, so hypotension is late.
• Tachycardia and narrowed pulse pressure precede hypotension.
• An anaemic woman has no reserve, so the same loss kills.
• Massage and bimanual compression act instantly; drugs take minutes.
• Ergometrine is contraindicated in hypertension and pre-eclampsia.
• Carboprost is contraindicated in asthma.
• Tranexamic acid is given within three hours of onset.
• Escalate to balloon, compression sutures, devascularisation, embolisation.
• Delayed hysterectomy in a coagulopathic woman is a common contributor to death.
• Secondary haemorrhage is retained products or endometritis, often both.
• Praevia is painless with a soft uterus; abruption is painful with a tense uterus.
• In abruption the visible loss understates the actual loss.
• No vaginal examination in suspected praevia until the placental site is known.
• Abruption causes disseminated intravascular coagulation through thromboplastin release.
• Vasa praevia bleeds fetal blood, so the fetus deteriorates rapidly.
• Accreta risk multiplies with previous caesarean plus praevia.
• Accreta incidence rises with the caesarean rate.
• Antenatal diagnosis of accreta is what allows planned safe delivery.
• Uterine rupture often shows fetal heart changes first.
• Inversion causes shock out of proportion to loss; replace before removing the placenta.
• Amniotic fluid embolism is a diagnosis of exclusion, managed supportively.
• In cord prolapse elevate the presenting part and minimise cord handling.
• Puerperal sepsis spans membrane rupture to 42 days postpartum.
• Group A Streptococcus can progress to septic shock within hours.
• Antibiotics will not sterilise retained products; evacuation is needed.
• Pregnancy satisfies every element of Virchow triad.
• Thromboembolic risk is highest in the puerperium, and the left leg predominates.
• Low molecular weight heparin does not cross the placenta; warfarin is teratogenic.
• Any woman of reproductive age with abdominal pain needs a pregnancy test.
• An empty uterus above the discriminatory zone suggests ectopic pregnancy.
• Methotrexate suits a stable small unruptured ectopic with a low hormone level.