Posted on May 4th, 2014 by wombwithaviewblog.com

A reader asked me recently about a “nub” pointing up or out as a means to determine gender early on in pregnancy around 12 Weeks. You might know it as the Nub Theory.

Yes, there is some school of thought regarding the “angle of the dangle” as she put it!  I’ve said before that both boys and girls each have tissue that protrudes at this gestational age.  First, imagine a fetus lying on his or her back.  Now if this little bit of tissue is sticking straight up, the thought is boy.  If the tissue is sticking straight out, as in parallel with baby’s spine, the thought is girl.

Baby Girl at 12wks, but be careful! The Nub Theory is only about 73% accurate!

12 Week Baby Girl, Nub Theory

I can tell you from personal experience that this little experiment does NOT always..let me repeat..does NOT always turn out to be correct. Sometimes the tissue is equivocal in direction, meaning it doesn’t appear up or out but half-way.

As part of early genetic testing, my co-workers and I obtained certification for Nuchal Translucency testing. During our training, the sonographer providing the training stated that sex determination is about 73% accurate when Baby’s position is perfect. Hmm, is that really enough of a percentage to rely on to paint a nursery? Not for me.

There was one patient for whom I had scanned all five of her pregnancies. She wanted me to guess at 12 Weeks, and we talked about how it was early and the Up or Out Theory. Baby’s “stuff” stuck straight out like a little girl, no question; no equivocal findings, no halfway nub. Just like in the above image! Textbook finding for a baby girl as defined by the above method.

 

Boy, oh boy! Were we surprised at her anatomy screen! And I mean boy! His parts were very easily seen. No doubt. After this, I never guessed at 12 Weeks again!

My patient didn’t really care which sex she had. They had boys and a little girl so they were thrilled either way.  But I will caution the patient who is strongly desiring one sex over the other. You do start to become emotionally attached to this “supposed” baby boy or girl and if it’s determined later that the info is incorrect, patients tend to be sad for the sex they “lost”. So, for this very reason, I’ll stick to my guns on gender prediction before 18 Weeks.

And now you know why!

So, I’ll say it yet again..NOTHING, absolutely nothing in life or medicine is ever 100%! 😉

Comments: 2 Comments »

2 thoughts on “Up or Out?

  1. Anna says:

    This is exactly what my ultrasound looked like at
    15 weeks. Does this mean the baby is a boy also?
    I got some serious baby brain and got confused at your
    Posting plz help 🙂

  2. Hi, Anna! Wow. I apologize and don’t know how I missed your response! If you see this, let me know what you had!

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