If the woman has an adequate haemoglobin level (or 'Hb') by the time her labour starts and she experiences a postpartum haemorrhage, she is more likely to physically tolerate a heavy bleed. This means the woman will be less affected by it and have less chance of needing interventions, including a blood transfusion if the haemorrhage is severe.
Having a well balanced diet high in iron and taking iron supplements if the Hb blood tests taken during the pregnancy were low (supplements are not recommended to be taken routinely if the level is normal, or above 11.5 gm /dl), will help keep the woman's haemoglobin at an acceptable limit.
Minimum limits of a recommended haemoglobin level in labour will vary from caregiver to caregiver and hospital to hospital. An absolute minimum low level would be 10 to 10.5 gm/ dl. This is the guide often used by birth centres. Some caregivers recommend 11 gm/dl or more. You may wish to read more in about iron during the pregnancy.
There are some caregivers who will recommend precautionary measures for women planning a vaginal birth, who could be at an increased risk of having a postpartum haemorrhage (for example if they have experienced a PPH with a previous birth).
These can include:
Taking a blood sample
Putting in an IV cannula
Having the baby in a delivery suite
Taking a blood sample.
When the woman arrives at the hospital in labour a sample of blood is taken to check her haemoglobin level and her blood group, The blood is also 'cross-matched' for compatibility with stored donated blood, in case a blood transfusion is necessary (this is a routine procedure for any woman having a Caesarean birth). The 'cross match' test is called a 'Group and Hold'.
Putting in an IV cannula.