Include

[Twiggz]

Just basing this on the pic above:

I wouldn't be jumping to the gravid issue at all......they still seem rather small. Adults will get up to round a total of about 10cm in total length. From the pic they only look bout half that- but i could be wrong.

How old are they roughly?

If they are still rather young i'd be more concerned as to whether the temp is adequate.
You should be keeping young milii at around 27-29deg until they are close to adult size.
What temps are they kept at?

Normally when the temp is down, they will go off their feed- normal.

JMO
Hope it helps is some way.