In the abdomen there may be an exacerbation of pre-existing herniae, but this is not very common. Constipation is a frequent complaint and this has been attributed to reduced peristalsis, but other factors are also involved. A relaxed bowel leads to constipation, which can get worse if the pregnancy progresses. It is important to eat plenty of fruits and fibre, as well as drinking plenty of water. The worse the constipation the more likely you will get hemorrhoids.
A good diet is the key to avoiding constipation, as well as exercise. If the problem gets worse try bulk laxatives such as Lactulose. If the problem is getting started with your bowel motion insert two glycerine suppositories and try again about 30 minutes later. Enemas can be used for resistant constipation.