Uterine Atony: The Leading Cause of Postpartum Haemorrhage

After birth, your uterus is supposed to contract firmly to stop bleeding from the area where the placenta was attached. When it doesn’t, blood vessels remain open, and heavy bleeding can begin within minutes. This failure of the uterus to contract is called uterine atony, the single most common cause of postpartum haemorrhage (PPH). Recognising its warning signs early and responding quickly can mean the difference between a routine recovery and a life-threatening emergency.

Pregatips

Labour may feel like the hardest part of childbirth, but the first few minutes after delivery are just as critical. As soon as the placenta detaches, hundreds of tiny blood vessels in the uterine wall are left exposed. Normally, powerful contractions clamp them shut, preventing blood loss.
When these contractions don’t happen, or are too weak, the uterus stays soft and fails to “tone up.” This is uterine atony. It accounts for nearly 70–80 per cent of all postpartum haemorrhage cases, according to the World Health Organisation (WHO). In India, PPH remains one of the top three causes of maternal death, yet it is almost always preventable with prompt care.

Understanding why uterine tone matters and what causes it to fail helps you grasp why doctors act so urgently during the minutes after birth.

What Happens in Uterine Atony

After the baby is born, the uterus normally contracts to about the size of a grapefruit within minutes. These contractions compress the blood vessels that supply the placenta. In uterine atony:

  • The uterine muscle (myometrium) doesn’t contract effectively.
  • Blood vessels stay dilated and open.
  • Bleeding continues from the placental bed.
The result is postpartum haemorrhage (PPH), defined medically as blood loss of more than 500 ml after vaginal birth or 1000 ml after a caesarean section. However, any heavy bleeding causing dizziness, pallor, or rapid pulse is an emergency regardless of volume.

Why It Happens: Causes and Risk Factors

Uterine atony can occur in any delivery, but some situations make it more likely.

1. Uterine Overdistension

When the uterus has been stretched too much, its muscle fibres lose their ability to contract effectively.

2. Prolonged or Rapid Labour

A uterus that has worked for too long, or too fast, can become exhausted and fail to contract afterwards.

3. Oxytocin Fatigue

If high doses of oxytocin were used during labour induction or augmentation, the receptors can become less responsive (known as oxytocin desensitisation).

4. Retained Placental Fragments

Even a small piece of placenta left behind prevents the uterus from closing properly.

5. Infection or Inflammation

Chorioamnionitis and endometritis interfere with muscle tone.

6. General Anaesthesia or Tocolytics

Certain drugs (such as magnesium sulphate or nifedipine) relax smooth muscle and may inhibit contraction.

7. High-Risk Maternal Conditions

Anaemia, pre-eclampsia, or obesity increase the chance of PPH and atony.

How Doctors Recognise Uterine Atony

The first sign is usually excessive bleeding immediately after birth. Doctors and nurses watch closely during the “fourth stage of labour” (the first hour postpartum).

Key clinical findings include:

  • Soft or ‘boggy’ uterus: When gently pressed, it feels spongy instead of firm.
  • Rising fundal height: The uterus balloons upward as it fills with blood.
  • Heavy vaginal bleeding: Bright red, often continuous or pooling under the patient.
  • Signs of shock: Rapid heartbeat, falling blood pressure, dizziness, pale or clammy skin.
Diagnosis is mainly clinical, and immediate treatment begins while the cause is confirmed.

Emergency Management: Step-by-Step

Doctors follow a strict, time-sensitive protocol for uterine atony. The priority is to restore tone and stop blood loss quickly.

1. Uterine Massage (First Response): The uterus is massaged firmly through the abdomen to stimulate contractions. You might feel pressure or discomfort, but this can save critical time.

2. Medications (Uterotonics): If massage doesn’t work, drugs that tighten the uterus are given sequentially:
  • Oxytocin (IV or IM): The first-line treatment.
  • Methylergometrine (IM): Increases contraction strength, but is avoided in high blood pressure.
  • Carboprost Tromethamine (PGF2α) (IM): Used if bleeding continues; avoided in asthma.
  • Misoprostol (PGE1) (rectal/oral): Heat-stable, widely used in low-resource settings.
3. Identify and Remove the Cause: Doctors check if a piece of placenta is retained or if trauma (like a vaginal tear) is contributing.
4. IV Fluids and Blood Transfusion: Restores circulating volume while definitive treatment continues.
5. Mechanical or Surgical Methods (if medications fail):
  • Uterine balloon tamponade (Bakri or condom catheter): Applies internal pressure to stop bleeding.
  • Compression sutures (e.g., B-Lynch technique): Physically compress the uterus.
  • Ligation of uterine or internal iliac arteries: Cuts blood flow temporarily.
  • Hysterectomy: As a last resort when bleeding cannot be controlled.
These interventions are usually successful when initiated early.

How It’s Prevented

Most uterine atony can be prevented through active management of the third stage of labour (AMTSL), a WHO-recommended protocol. AMTSL involves:

  • Administering oxytocin (10 IU IM) immediately after birth.
  • Controlled cord traction to deliver the placenta safely.
  • Uterine massage after placenta delivery to ensure firmness.
Other preventive steps:

  • Checking that the uterus is firm before leaving the delivery room.
  • Monitor blood loss closely for the first hour.
  • Treating maternal anaemia during pregnancy to reduce risk.
In India, these practices are standard across most hospitals and government maternity programmes under the National Health Mission (NHM).

What Recovery Looks Like After Uterine Atony

With timely management, most women recover fully. You may feel uterine soreness for a few days and fatigue from blood loss. Post-treatment care includes:

  • Iron and folic acid supplementation to rebuild red blood cells.
  • Antibiotics are used if an infection risk is present.
  • Rest and hydration to restore strength.
Follow-up scans or check-ups may be scheduled to ensure the uterus returns to normal size (involution) and that no clots or retained tissue remain.

Possible Complications (If Left Untreated)

If uterine atony isn’t managed promptly, complications can escalate quickly:

  • Severe haemorrhage and shock.
  • Disseminated intravascular coagulation (DIC), a dangerous clotting disorder.
  • Organ failure due to reduced oxygen supply.
  • Emergency hysterectomy to save life.
  • Maternal death, though rare in facilities with skilled birth attendants, is still a risk in unattended home deliveries.
This is why post-delivery observation for at least one hour is non-negotiable in modern maternity care.

Emotional Impact and Support

Experiencing heavy bleeding after birth can be frightening. Many women describe feeling disoriented or traumatised afterwards. Emotional recovery matters just as much as physical healing.

  • Talk openly with your healthcare provider about what happened.
  • Ask follow-up questions to understand how your recovery is progressing.
  • If anxiety or intrusive thoughts persist, consider postpartum counselling.
Knowing that uterine atony is common, treatable, and rarely fatal with prompt care often helps mothers regain confidence after such an event. Uterine atony may sound alarming, but awareness and swift action save lives every day. It’s a reminder that birth doesn’t end with the baby’s cry minutes that follow are just as vital.

With trained care, routine oxytocin use, and vigilant observation, most cases of atony and postpartum haemorrhage are entirely preventable. Understanding what it is and why it happens helps you recognise that safety in childbirth isn’t only about delivery—it’s about everything that happens right after.

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FAQs on Uterine Atony: The Leading Cause of Postpartum Haemorrhage

  1. Can uterine atony happen after a C-section?
    Yes. The risk exists after both vaginal and caesarean deliveries, though slightly higher with prolonged labour or multiple pregnancies.
  2. How quickly does uterine atony cause heavy bleeding?
    Usually, within the first 10–15 minutes after delivery, which is why constant observation in that period is crucial.
  3. Can it happen again in future pregnancies?
    The risk is slightly higher if you’ve had atony before, but preventive oxytocin and careful monitoring make recurrence uncommon.
  4. Is there anything I can do during pregnancy to prevent it?
    Keep anaemia under control, attend all antenatal visits, and ensure delivery in a facility equipped to manage emergencies.
Disclaimer: Medically Approved by Dr Mannan Gupta, Chairman & HOD, Obs & Gynae, Elantis Healthcare, Delhi