Count the first day of your menstrual period as Day 1.

The first day of your menstrual period is day one.

The first phase starts with the first day of your period or blood flow.

The second test must be given during the first 5 days of your menstrual period just before you start taking acitretin.

You pregnancy due date is normally about 280 days (40 weeks) from the first day of your last period.

All you need to know is the first day of your last period.

The red bead is the first day (day 1) of your period.

Who the hell kept track to the day of their period?

The injection can be started up to and including the fifth day of your period.

Pregnancy is measured in weeks from the first day of your last menstrual period.