Actually, this “OB” year would be just a little short, the real solar year being 13 perfect months and about one and a quarter day.I know I could figure out something to do with that extra one day, five hours and forty-nine minutes.In other words, we don’t care if your baby is born at 38, 39, or 41 weeks.But we surely need to know when 40 weeks is so that we can be correct in stopping your labor at 33 weeks.The due date is referred to as the estimated date of confinement (EDC).This is a throwback to the days when a woman was “confined” to bed and home for a period of time after birth until convalescence was complete.These intervals have been called “lunar” months in the past, coinciding with the repetitive phases of the moon.The word “menses,” from which is derived “menstrual” cycle, is a Latin connection with the word for moon.
It is no coincidence that the average menstrual cycle lasts twenty-eight days.
The importance of the due date to the obstetrician is emphasized when your baby chooses a date remote from the calculated due date.
Worries about going beyond your due date apply as well.
It was a term contemporary with the “lying-in” that meant the same thing.
By the time you’re “late” for your period, that period which will never come, you are already two weeks past the time of conception.