Most lower abdominal distension during pregnancy is a physiological condition.
As the uterus increases in size during pregnancy, the surrounding organs or due to pressure on the stretched ligaments and tissues may experience a sensation of distension, which usually manifests as a vague pain and is not intense in degree. Some pregnant women who have chronic pelvic inflammatory disease may also experience lower abdominal distension and pain as the pelvic tissues become more congested and oedematous after pregnancy.
However, it is important to note that some pregnant women also experience lower abdominal distension due to pre-eclampsia, which may be accompanied by redness and should be treated promptly at the obstetrics department.