Babies do not actually breathe in utero. They do, however, practice breathing movements.
But what are fetal breathing movements?
Fetal breathing movements is a phrase we use when we see your baby’s diaphragm involuntarily move back and forth intermittently. Now for Diaphragm 101 in case you didn’t already know! The diaphragm is essentially a sheath of muscle that separate our chest from our abdomen.
Also, it plays a key role in respiration as soon as breathing air is a necessity. When we want to take in a deep breath, our diaphragm pushes our abdominal organs down to make room for our lungs to expand and fill with air. Incredible, right? See the image below for a cross section of Baby’s belly. The diaphragm is the faint gray line between the three arrows.
Very often patients notice that my probe is fixed in one spot as I watch the diaphragm move. Naturally, they want to know what I’m doing and what they see moving on the monitor. When I respond that I’m watching fetal breathing movements, they usually reply with, “I didn’t know babies can breathe in there!”
And then I explain that Baby’s lungs are the last organs to mature, so a fetus cannot actually use their lungs until they’re born. Moreover, because they are surrounded by fluid, babies cannot take the fluid into their lungs. What typically follows is a sheepish, “Oh, of course. Don’t I feel dumb!” No way. Who would know if you didn’t study a fetus for a career?!
When can you see the breathing movements?
I’ve personally noticed fetal breathing movements as early as 14 Weeks, but we expect to witness them routinely from 32 Weeks. We also refer to them as respirations. These fetal breathing movements are part of the criteria to determine fetal well-being as a part of a BPP or Biophysical Profile.
Sometimes, we don’t see these movements when we expect to see them when performing a BPP. It’s often not a cause for concern. We do not expect to see continuous breathing movements while Baby lives in the warm comfort of his temporary home. Until they make their grand entrance and need to take their very first real breath, it’s only practice!
Just one more of the cool aspects of scanning your baby. We all learn something new every day, right?
If you have a video of your baby practicing respirations on ultrasound,
I’d love to attach it to this post!
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As always, thanks for visiting my blog!