Primary postpartum haemorrhage: heavy bleeding in the first 24 hours after birth

After the baby and placenta are delivered, the womb normally contracts firmly and squeezes the blood vessels shut. Primary postpartum haemorrhage is defined by the Royal College of Obstetricians and Gynaecologists as blood loss of 500 ml, about a pint, or more within 24 hours of birth. Loss between 500 and 1,000 ml is minor, and above 1,000 ml is major.

Bleeding that happens from 24 hours up to 12 weeks after the birth is called secondary PPH and is managed differently, often with antibiotics if infection is suspected.

Clinicians sometimes remember the causes as four Ts: tone, tissue, trauma and thrombin. Poor contraction of the womb (tone) is the commonest. Part of the placenta or membranes left behind (tissue) stops the womb closing. Tears or a surgical cut (trauma) bleed directly. A blood-clotting problem (thrombin) can make any bleeding harder to control.

The leaflet is clear that most women will not have a haemorrhage and that many with a primary PPH had no obvious risk. Some factors increase the likelihood, and staff use them to plan where and how to give birth.

• Before labour: placenta praevia, placental abruption, multiple pregnancy, pre-eclampsia or high blood pressure, a previous PPH, a BMI above 35, anaemia, fibroids, clotting disorders and anticoagulant treatment.

• During labour: caesarean birth, induction, retained placenta, perineal tears, instrumental delivery, a long labour of more than 12 hours, a baby over 4 kg, a first birth over age 40, fever in labour or general anaesthesia.

The standard step is an injection given as the baby is born, which makes the womb contract and helps the placenta separate. If you are at higher risk, extra medicines and a drip may be arranged in advance. Your midwife may also check the placenta carefully, repair tears promptly and keep your bladder empty, since a full bladder can stop the womb tightening.

The response escalates with the amount of bleeding. First steps include rubbing the top of the womb to encourage it to contract, a second dose of medicine, a catheter, fluids through a drip, inspecting the placenta and repairing any tear.

If bleeding continues, more medicine may be given by injection or into the back passage, oxygen and a second line are set up, blood or clotting products may be transfused, and a balloon can be placed inside the womb to press against the bleeding surface. An operation may be needed in theatre, and a radiologist may block blood vessels in a procedure called uterine artery embolisation. The RCOG notes that very occasionally a hysterectomy is needed as a life-saving measure.

After a bleed, you may stay in hospital longer, be given iron treatment and have a blood count checked by your GP at about six to eight weeks. Because a haemorrhage raises the risk of clots, the RCOG says heparin injections and compression stockings are offered for 10 days after delivery.

It is common to feel exhausted, light-headed or low in mood after losing a lot of blood. Ask for support with feeding and caring for the baby, and tell your midwife if you develop dizziness, a racing heart or breathlessness.

Having had a primary PPH raises the chance of another in later pregnancies. You should be offered a plan before the next birth, which usually includes giving birth in a consultant-led maternity unit, having a drip put in during labour and receiving preventive medicines. Treating anaemia during pregnancy gives you a bigger reserve.