Hemorrhoids are swollen veins in the rectum (rectum) and around the anus. They are closely related to varicose veins, which you see on your legs. If these veins are irritated, the surrounding tissue also swells, burns, infects and bleeds. Hemorrhoids are caused by excessive pressure in the rectum, forcing blood into the veins. Sometimes they burst. Hemorrhoids occur within the anus (internal hemorrhoids) and under the skin around the anus. An internal hemorrhoid can extend through the skin.
Sitting for long periods without moving, abdominal distensions, sitting on the toilet for long periods of time, constipation which leads to excess pressure on the anus, diarrhea, birth and the pressure and extra weight of baby pushing down, birthing a baby, the effects of aging and the muscles becoming less taut, severe coughing and heavy lifting
Hemorrhoids are generally not dangerous, but are very uncomfortable. Rubbing, excessive cleaning or scratching makes the problem worse.
Hemorrhoids in pregnancy
Having hemorrhoids in pregnancy is normal. It is because the baby exerts pressure on the stomach, but also from hormonal changes that swell the susceptible veins. Even during birth, these veins are tested. Usually pregnancy hemorrhoids are temporary and disappear after birth. During an exam, the doctor may notice the swollen veins. The doctor can investigate internal haemorrhoids with various devices, for example with a rectal proctoscope, or with a rectoscope, which allows the entire rectum to be examined.
From angelababy In Q&A