Babys brain

I'm 31 weeks pregnant with Twins (boy,girl) all of my ultrasounds have been good no problems until today. Doctor came in and told me baby one which is (female) one of left ventricle messured at 10 1/2. I had ask how come this  came up now and she told me my last visit it was at 10 and was not a problem.  I got really upset and she did mechane a MRI for babies but she didn't think I needed it yet. I'm supposed to go back in two weeks to have another check up. My question to you is does this some time happen ? Will it fix itself ? What does the number have to be in order for it to be a problem ? What would be the worst out come of all of this with no complications so far ? I have a feeling she will be ok and things will work out, I'm just scared.

[Yao Sun, MD, PhD]

Generally speaking, ventricular enlargement is considered within normal limits if it is less than or equal to 10 mm, particularly if it only involves one side.  The risks for long term neurodevelopmental problems are low if the ventricle stays at this size and no other abnormalities are found.

If the ventricles continue to enlarge to greater than 10 mm, it increases the risk of possible long term neurodevelopmental problems but does not necessarily mean that your baby will have them.  Follow-up ultrasounds will give more information about whether the ventricle is truly enlarging.  The measurement of ventricles is not an exact science since it depends a bit upon the technique used for each ultrasound.