Primulot contains norethisterone which helps to delay periods. Again norethisterone is used to prevent women from becoming pregnant. It works by preventing the release of eggs from the ovary and changes the lining of the uterus which makes it difficult for an egg to develop. It also increases the thickness of vaginal fluid which can stop a sperm from reaching an egg. But this contraceptive effects are present only if it is taken regularly. Though amenorrhea is no more a reliable sign of your pregnancy do a regular urine pregnancy test until the upcoming mensturation. If you want to continue your pregnancy its recommended to stop this drug as this have harmful affect on milk production. If your pregnancy test becomes positive its necessary to visit a gynecologist.