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.
No one is sure what causes ovulation pain. But here are a few theories. During ovulation, a follicle on the ovary ruptures and expels an egg. This releases some extra fluid, and the extra fluid may lead to a dull ache. The sharp, sudden pain some women feel may be caused by the egg itself, bursting out of the follicle.