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.
There are certain signals your body might send that should prompt you to take a pregnancy test. For the best results, take the test after you think youâve missed your period. Test during your first morning bathroom visit, or hold it for several hours to increase the concentration of the HCG hormone that the test measures.