1. Open Excel software
  2. Lay out prenatal record (or any record where you want dates to change based on a set date in the record)
  3. In the fields (or cells) where you want a date on the record to adjust, type in a formula - For example: in a cell on the form for a test that happens at 6 weeks gestation, the formula would be: =SUM(J2+42) J2=the date for the patient's last menstrual period, or LMP, and "42" is 42 days (or 6weeks x 7days/wk) from that date.
  4. If you are crafting a prenatal record, you will calculate all of the important dates one time - then, just by changing the due date, all of the other dates will change, too.