Most health professionals count week 1 from the first day of your last period – in which case, you are not actually pregnant at all. However, this is how doctors project when your due date will be.
It can be hard to determine when you fall pregnant, but many women know when they got or get their period, making this a useful method for projecting the baby’s due date.
Roughly two weeks after your period your body will release an egg (a process called ovulation), which is then able to be fertilised by sperm. It’s at this point, towards the end of week 2, that conception will actually take place.