Pelvic pain and problems urinating may mean you have a bladder infection. Flank pain with fever and urinary symptoms may mean you have a kidney infection(pyelonephritis). Flank pain is felt just below the rib cage and above the waist. It can be on one or both sides of the back. If you have pelvic or flank pain and other symptoms of a bladder or kidney infection, call your doctor.
An ectopic pregnancy(tubal pregnancy or extrauterine pregnancy) occurs when a fertilized egg attaches (implants) to an area outside of the uterus. Belly or pelvic pain that occurs with a missed period early in pregnancy is the most common symptom of ectopic pregnancy and occurs in about 75% of women who have an ectopic pregnancy.
In an ectopic pregnancy, the fertilized egg may implant in a fallopian tube, ovary, or in the abdomen. These organs can't hold the growing baby. Pain develops when the baby grows and the organ is not able to stretch bigger.
Pelvic or lower belly pain caused by ectopic pregnancy may get worse when you move or strain. The pain may occur sharply on one side at first and then spread across the pelvis.
Severe cramps during pregnancy, with or without heavy bleeding, may be a sign of a miscarriage. The cramping can be so severe that you cannot move, or it can be mild. You may also pass large blood clots or gray or pink tissue.
Belly pain during later pregnancy, especially close to delivery, can be caused by other problems, such as preterm labor or placenta abruptio. Call your doctor for instructions if you have moderate to severe belly pain at any time during your pregnancy.