Physical examination was unremarkable: there was no palpable adenopathy; breath sounds were clear to auscultation bilaterally in all lung fields; there were no appreciable murmurs, rubs, or gallops; there was no organomegaly or tenderness on abdominal examination; there were no appreciable rashes on examination of the skin; and there were no sensory ...
1 Each follicle contains an immature egg (ovum) but only one follicle usually survives to maturity. It is supposed that ovulation pain is caused by the expanding follicle stretching the membrane of the ovary.  Ruptured follicle - when the egg is mature, it bursts from the follicle. This may cause slight bleeding.
Ovulation may also cause a particular kind of cramping called mittelshmerz (literally middle pain). Not everyone gets it, but those who do tend to feel a dull, aching pain on one side of their lower stomach. The side that's painful corresponds to the ovary that's releasing an egg that month.