My app shows one week more than what I thought from ovulation date. The doctor asked my last period date and calculated from that. Why is it counted like this, can someone explain?
My gynac told me they count from the first day of ur last period, not from conception. So its about 40 weeks total even though u actually conceive around 2 weeks in. The early scan also helps confirm the dates.
Oh I was confused by this too, I thought it counts from when u get the positive test. But its from the last period date apparently. My doc adjusted mine after the scan since my dates were unsure.
They go by ur LMP, the last period date. Doc counts 40 weeks from there and gives u a due date. If ur cycles are irregular the dating scan corrects it.
The apps and doctors both calculate from ur last menstrual period date. Thats why its 9 months but technically 40 weeks. The first ultrasound usually fine tunes the due date based on baby size.
