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.
Two main types of pregnancy tests can let you know if you're pregnant: urine tests and blood tests. Urine tests can be done at home or in a doctor's office. Many women first choose a home pregnancy test to take about a week after a missed period. Home pregnancy tests are private and convenient. These products come with instructions. Follow them closely for the most accurate results. After testing, you can confirm results by seeing your doctor, who can perform even more sensitive pregnancy tests.