Delayed cycle. Is there anything wrong?

My wife got her period on 30th march for 3 days.Since its a 28 day cycle, her next period was expected on 28 april or so.. We also had an unprotected intercourse on 6th april but i din ejaculate inside her. She din get her periods in the expected date in april following which we did 2 home pregnancy test and one hcg test, all of which were negative.we decided to see a doctor but then she got her periods on 8th of may. So it kind of became a 40 day cycle. Is it anything serious or it can be ignored?off late her weight has increased all of a sudden and she also has got acne problem from past two months.she was detected with a minor pcod 2 years back but doctor didnt prescribe any medicine and told to take care of diet and exercise.she sometimes notices slight pain in the extreme corners of the lower stomach, alternately any sides. Is there anything wrong?