United States of Europe - History. 1  Various versions of the concept have developed over the centuries, many of which are mutually incompatible (inclusion or exclusion of the United Kingdom, secular or religious union, etc.).
Due Date Calculator. This interactive Due Date Calculator will help you estimate the date your baby will arrive. Pregnancy usually lasts 280 days (40 weeks) from the first day of the woman's last menstrual period.This calculator is a general guide: every pregnancy is unique, and sometimes babies arrive sooner or later than expected. Always talk to your health care provider about your due date.ertilization of the egg usually takes place 14 days before the woman's next period. If your menstrual cycle is shorter or longer than 28 days, select the number of days from the start of one cycle to the start of the next cycle.
Evaluating Your Cycles. Due dates are accurate if you have regular monthly periods; obstetricians often calculate the due date based on the first day of a woman's last menstrual period, says Dr. Draion Burch, Pennsylvania-based obstetrician-gynecologist. However, women who have irregular periods can have inaccurate dates determined, he says.