Determining Due Dates – Timed vs. Ultrasonic

It turns out that there are two ways to determine the baby’s due date. Neither are very exact, but since it’s quite wordy for someone to say that we’re due the “last quarter of May, first quarter of June”, they just give us a single date.

Of the two ways to determine a due date, Timed is the method you use from the beginning, where the doctor takes into account certain physiological (gals, you know what I mean…guys, you don’t need to know) dates, use their little magic wheel of baby time, and figure out when 9 months (or 40 weeks) will occur. To me, this seems like the method that makes the most sense.

The second way of determining a due date, which I call Ultrasonic, is done by measuring the ultrasound image. The doctor measures the baby, then thinks to herself, “hmmmm…if the baby is 1 pound 15 ounces, with a head diameter of 200 mm, abdomen diameter of 220 mm, and femur length of 35 mm, then I would guess that the real due date is 6 days earlier!” (actually, she just punches these numbers into her ultrasound machine and it chugs out the date)

Now, to answer Amy’s question of 2 days ago, either the baby is coming 6 days earlier than originally expected, or the baby is 6 days bigger than the ultrasound machine expects him to be when he’s born! Uhhhhh…I bet you can guess which theory Sarah prefers…

But both methods are accurate to +/-2 weeks, so this whole entry was immaterial anyways!

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6 Responses to Determining Due Dates – Timed vs. Ultrasonic

  1. Grt. Grandma says:

    Hi, since we are all so anxious, maybe Baby Fredman can be born on Great Grandpa Fredmans birthday, May 15th. And if he isn’t ready to make his journey into this big world, he can wait and have itJune 12th and make a Grandpa pretty proud. Of course Grandpa will be proud whenever he appears on the scene. I like the hours Grandpa at Pillager picked….Love to all, GG

  2. Josh says:

    > But both methods are accurate to +/-2 weeks, so this whole
    > entry was immaterial anyways!

    So the conclusion is really this: “We can accurately identify the month of conception, and make a reasonable guess about the birth month.”

    That first method has always bothered me because certain physiological dates (hah, I figured it out!) are just a boundary condition…

  3. Aunty Beth says:

    I think it’s about time for him to just hurry up and get here. It’s hard to spoil him when he’s not actually holdable yet. 🙂

  4. Grandpa from Pillager says:

    Good thing nobody can predict the time and day of Baby Fredman’s arrival. His arrival time and day are the first major decision he will make in life. It is my belief (based on experience) that he will choose to arrive sometime between 1:00 AM and 5:00 AM.

  5. Grandma from Pillager says:

    As for me, “our” baby can’t come soon enough. (Amy and I had a conversation about identifying the baby as “ours. We decided we’d keep on doing it)
    There was a discussion in the teacher workroom yesterday about who was having what. (Five teachers are pregnant.) One of the teachers didn’t know about our baby grandson (she had to be the only one left that did not know!) and just for fun said, “And what are you having, Lenora?” I promptly answered, “a boy”. Too bad someone someone quickly clearified by saying, “She’s going to be a grandma.”
    Back to the due date item, “I’ll be patient and wait for baby grandson to come when he is ready.”

  6. Grt. Grandma says:

    All of this is quite educational Sarah, how ever, I think the old wives tale is that boys come earlier. However I don’t want to down play the medical community, but expeirence tells me the “old wives tale” can be pretty accurate….Love gg

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