Male Fetal Sex Determination
So often, when readers send me their images for a second opinion on fetal sex, I just cannot provide a confirmatory guess. This is either due to too early gestational age, too poor an angle, or too poor an image. Sometimes, it is a combo of all three!
Ultrasound is such a different animal because it is nothing like a photograph. In a photo, you can see what’s in the distance or up close to the camera. With ultrasound, we cannot. We can only see exactly what is directly under the probe. It is a 2D (two-dimensional) image only, and we have to move the probe around to obtain different angles to create that “photograph” in our minds. And there are so many variables that go into creating a good ultrasound image.
Since ultrasound is completely subjective and observer-dependent, some sonographers take great images and some . . . well . . . don’t. It’s much like comparing a professional photograph to an out-of-focus, too dark, cell phone group portrait where everyone has red or white eyes. You know, the ones you always see posted on social media?
I am too much of a perfectionist. This wasn’t always a good thing when trying to take keepsake photos for patients because it caused me to run late on more than one occasion! And everyone knows people don’t like to wait in a medical office. It’s just a learned skill and some are simply better at it than others. Some just don’t tweak all the knobs as much as they should. Maybe they were never really taught how to do so very well from the start.
A Poor Image Can Limit a Fetal Sex Guess
Some factors that cause a poor image are just beyond a sonographer’s control . . . like an uncooperative fetus, extra weight around a patient’s abdomen, or a gassy patient. The laws of ultrasound physics dictate that the further sound waves have to travel, the poorer the image. Also, sound does not travel well through air or gas. I’ve scanned heavier patients where I could see pretty well and thinner gassy patients where I struggled to see at all!
That said, I can tell when someone else’s image is not great or when she didn’t work with all the knobs. This can make reading an image snapped by someone else extraordinarily difficult. One image represents only one angle. Scanning real-time allows me to look from all angles possible, where I can subjectively determine my confidence in fetal sex–or whether a guess is too risky at all.
ALL that said, sometimes taking a second guess is easy-peasy! Check out the email I received from a reader about whether her baby is male. Her images didn’t leave much of a question in my mind! She was just over 20 Weeks along.
Can you tell this is a boy?
mama: Hello! I’ve been following your blog, and I was wondering if you could take a look at my baby’s scans and give me your opinion on gender. We were told it’s a boy, but I’ve read that girls can have parts that look similar to boys? I agree that it looks like a boy but wanted a second opinion. Thanks!
wwavblogger: LOL No ma’am! Little girls don’t normally look like that at 20 Weeks! I will wager my bet on a baby boy. 🙂 Congrats!
mama: Lol! I wasn’t quite sure, but I’ve had a feeling it’s a boy from the beginning of the pregnancy!
Reader mom: I forgot to mention in my reply to you that, yes, girls and boys can indeed look similar. But this is truer between the 12-16 Week range when parts are small, just developing, and when combined with other factors that come into play which result in limited view!
Did you guess boy?
If so, I agree! Compare the images I’ve edited below.
Even though it would be quite unusual for this to be a baby girl, I’m still always a bit cautious about guessing fetal sex based on someone else’s image. When I’m casting a vote for Team Blue, I like to ensure I see a scrotal sac which requires a slightly lower angle.
Sometimes, you can obtain both scrotal sac and penis in the same image, sometimes not. I get a slight impression of a scrotal sac here where I placed the circle. The sac at this age can appear quite small, and testicles are not expected to descend until about 26-28 Weeks. This is why scanning real-time helps; it allows me to see Baby at all angles possible while moving and stretching and opening his legs more.
Stay tuned! My next post will be one where a questionable and poorly technical image comes into play. Mom wrote back saying she delivered the opposite sex. Oops!
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