Haemorrhoids (or 'piles') are essentially varicose veins of the anus or 'rectal canal'. They can appear as one (or several) small lumps around the opening of the anus during pregnancy, often more common in the last few months, and can be made worse by having constipation during pregnancy or after pushing your baby out at birth.
Haemorrhoids can be painful (although not always) and are often quite itchy. They can also bleed, especially after a bowel motion. At times the bleeding can be quite bright and heavy.
Haemorrhoids are more common in women who have had a baby before and women with twins or more, but they can appear with first time mothers as well. The weight of the baby and the uterus apply pressure to the rectal area, allowing blood to reach the area but impeding it from draining away effectively. The blood then pools in the veins of the rectum and swells them. The pregnancy hormone 'progesterone' also makes the blood vessels relax, causing them to be less efficient at pumping the blood back.
Some women will describe a reluctance to push in labour when they have haemorrhoids. It may be that they feel uncomfortable or possibly embarrassed that their birth attendants and / or support people will see them. Haemorrhoids do not affect the actual birth process and perhaps being in a position that is not as exposing, such as sitting on the toilet, being in a bath may help.
If you had haemorrhoids during the pregnancy, or discovered them after the birth, they will probably be quite sore for a week or more. If you did not have them before the birth, they should eventually go away. However, if you have had them for some time, or if they are quite large, they may decrease in size, but remain. Particularly severe cases of haemorrhoids could require an operation in the months, or years after the birth. (Although most caregivers will advise waiting until the woman has completed her family, in case they return with a subsequent pregnancy.)