Change in size of lateral ventricles of baby's brain

Hello,

I am 24 1/2 weeks pregnant.  All first and second trimester screenings have been normal.  At my 20 week ultrasound, my OB was concerned because the baby's left lateral ventricle was at the top end of the normal range (measuring 10 mm).  I went for a level 2 ultrasound and the left ventricle was measuring between 8 and 9 mm.  Just to be safe, the high-risk asked me to return in 3 weeks for one more level 2 ultrasound, which was today.  We had a different ultrasound tech today, who did not seem as thorough as our previous tech.  She only measured the baby's left and right ventricles one time (the previous tech measured each one numerous times just to determine accurate measurements).  She measured the left ventricle at 7 mm today.  Is it normal for the measurements to actually go down (from 8-9 mm to 7 mm)?  It seemed that the right ventricle (even though it was not of concern) also decreased in size from 5-6 mm to 4 mm.  If you would please let me know if a decrease in the size of ventricles is normal, and if you think there is anything else I should be asking, I would greatly appreciate it.  Thanks!

[Yao Sun, MD, PhD]

The fact that your baby's ventricles are not increasing in size is reassuring.  A decrease in size is not concerning as long as no other abnormalities are found on the follow-up ultrasound.  The radiologist will be comparing the current ultrasound with the previous ones, and they will let your obstetrician know if they are concerned about the current one.  The ultrasound technician may only need to measure once if they get a good view of the ventricle during the measurement.

I'm glad to hear that ventricular size has remained in the normal range.

[AMS04]

I meant to indicate all first and second trimester genetic screenings have been normal...Also, there have been no other concerns from my 20 week or level 2 ultrasounds.

[AMS04]

Thank you very much!  I really appreciate your advice.

[Yao Sun, MD, PhD]

You're welcome!  It's nice to get follow-up to find out what's happening now.

[johnny31623]

A related discussion, Right Lateral ventricle was started.