"unilateral lower abdominal pain"

Monthly Mittelschmerz, Could It Be Evidence of Uterine Coldness?

You may have spent the whole day struggling with that persistent pain returning this month without fail. With sharp, localized discomfort on one side of your lower abdomen and a dull ache extending into your lower back, you might have worried whether it was a sign of a serious illness. That discomfort is mittelschmerz. Rather than dismissing it as a fleeting premenstrual issue, it may be an important signal sent by your body.