The most common cause of rib pain on the right side of the rib cage in pregnant women is because as the fetus grows, the uterus grows and the muscles in the rib cage are forced to pull causing pressure and in women with smaller hips or larger fetuses, the rib cage is even at risk of fracture. The pregnant woman’s uterus usually gains about 2-4 kg of weight and it exerts greater pulling forces on the rib muscles, while during pregnancy, maternal hormones are essential during this time. Progesterone, which is necessary for uterine contractions, softens the rib muscles and ligaments, making it prone to painful symptoms. However, a sharp increase in estrogen levels can also raise the chances of gallstone formation, and cholesterol can occasionally become large enough to cause rib pain without requiring special treatment if it is not too much of a problem. If the symptoms of right sided rib pain in pregnant women are not relieved in the short term and progressively worsen, it is important to seek prompt medical attention from a regular hospital.