Hemorrhoids are swollen and bulging veins in the rectum that may protrude through the anus. They can cause itching, pain, and bleeding. Up to 50 percent of pregnant women get hemorrhoids, but they don't usually appear until the second trimester.
Hemorrhoids are common during pregnancy for many reasons. During pregnancy blood volume increases greatly, which can cause veins to enlarge. The expanding uterus also puts pressure on the veins in the rectum. Plus, constipation can worsen hemorrhoids. Hemorrhoids usually improve after delivery.