The length of the menstrual cycle varies from woman to woman, although the average is 28 days. Cycles that last longer or shorter than this, ranging from 21 to 40 days, are typical. Menstruation will not continue indefinitely; after about five years, the uterine lining should be restored completely before a new cycle begins. Women have different reasons for delaying or skipping their period. If you fail to get your period by the third month of your pregnancy, see your doctor immediately. They may need to perform an ultrasound to confirm whether you're pregnant or not and if there's no evidence of pregnancy, they can advise you on when you might expect to start your period. Some women may believe that eating certain foods will bring them fertility or help their periods, but this isn't true. Your body is very efficient at removing any harmful substances you eat, so any particular food group isn't going to make a difference. Some women may think that if they eat lots of fruits and vegetables they won't get pregnant, but this is also not true. The only way to avoid getting pregnant is with contraception. Contraception is discussed in more detail below. Many women worry that if they don't get their period by the end of the first year of being married, then they may be pregnant. But this is not likely to be the case.