There are a few things the woman can do to prevent fainting, minimise it or help remedy it if it does occur. These can include:
Delaying getting up
Drinking lots of water
Getting up slowly
Shower with someone
Rest as much as possible
Delaying getting up.
Delay any move to the shower or getting up for prolonged periods until you are feeling OK (generally after 45 minutes to an hour or so, sometimes longer if the blood loss was heavier). It is acceptable to get up for short periods, for example to move to the bed if you gave birth off the bed, or to pass urine, but avoid standing for prolonged periods of time. If you do get up have someone with you and a chair close by.
Drinking lots of water.
Drink at least 4 large glasses of water or diluted juice, in the hour after giving birth, in addition to any other fluids such as a cup of tea or champagne. This will help replace body fluids and increase your blood pressure. If you do have some champagne or other alcohol soon after the birth, it is wise for the woman to limit it to about half a glass or so, as the alcohol can lower your blood pressure further and contribute to you feeling faint when you get up. (If the partner or support person is tired and needs to drive home, it is probably a good idea for them to limit it as well).
Getting up slowly.
When you do decide to get up, do it slowly. Make sure your caregiver is aware that you are intending to get up. They will probably need to check that your uterus is contracting and that your bleeding is controlled. They may also wish to make sure that the epidural has worn off if you had one.
Sit up in bed first (if you are not already), then sit on the side of the bed with your feet hanging down and stay there for a minute. If that feels fine then slowly get up, make sure someone is standing beside you, and sit again if you feel faint. If you are getting up from a mat on the floor or out of the bath, go onto your hands and knees first.