The doctor will advice you when he prescribes it to you after you have a positive pregnancy test. Just having your period a week delayed does not mean you are pregnant.
Because of bad weather in the area.
This Week in Horror - 2010 Not Bad for a Human 1-19 was released on: USA: 9 May 2011
Are you serious? you need to get yourselves a pregnancy test
Yes they can due to a variety of things namely anxiety or stress.
It depends how old you are.
June 10 2011 it was delayed a week
1
D-Day was actually delayed one day due to bad weather
Airline flights are often delayed. They get detailed most often because of bad weather conditions but also because of mechanical and maintenance reasons.
Its due to the baseball season in japan. see related link
You can start them whenever, but it is a possibility that your period will be delayed.