1 The heart's internal pacemaker regulates and times the beating of the heart via electrical signals.  Electrical signals start at the SA node, causing atria contraction, and then move on to AV node, delaying electrical impulses to allow blood from the atrium to fill the ventricles.
With the First Response new Early Response Twist Pregnancy Test, you can test as early as 6 days before your missed menstrual period. This is the only test that allows you to find out this early, as it is sensitive enough to capture the very scant amounts of the pregnancy hormone.
Best Answer: If you are doing one of the early ones you have to do it first pee of the day. if you are doing on the day your period due you can do it any time. Hoep this helps. Not really. Not anymore anyways. I know with the First Response pregnancy test that you can test at any time of day. Although the HCG hormone is more concentrated in the morning. However First Response detects the hormone the quickest so it's not necessary to wait until the next morning.