Pregnancy and childbirthing are predisposing factors of hemorrhoids, anal fissures and constipation.  The growing baby in your uterus during pregnancy and the delivery itself cause the veins to expand in the lower part of your body.

Pregnancy makes women more prone to hemorrhoids because the circulating blood volume during pregnancy increases which can increase venous engorgement, and a slowing in blood flow is caused by the enlarging pregnant uterus or a loosening of pelvic muscles.  In addition to the absence of valves in hemorrhoidal vessels and draining veins, chronic constipation, and genetic factors.