Primolut N contains progesterone and can be used to treat cycle irregularities due to progesterone deficiency. There are many causes of delay in periods and this medicine can be effective only in case of problems with progesterone phase of the cycle. If delay in periods is due to pregnancy then it will not induce periods but will strengthen the pregnancy with many harmful effects on the fetus. So, in case of delay in periods, first of all get pregnancy test if you are sexually active and then then get advice from the doctor if the test is negative.