I had sex with my wife and periods did not occur as per cycle. What are chances of getting pregnant. Please suggest ways of avoiding?

Condoms, pills, etc. Pregnancy is the most common cause of a missed period. If not pregnant, other causes of a late or missed period include: excessive weight loss or weight gain, increased exercising, emotional stress, having an illness, traveling, medicines (especially birth control pills), hormonal disorders, etc… a visit to one’s ob-gyn doctor is a good idea if symptoms are persistent, recurring, or worrisome.