What is your reason for fasting in the 3rd trimester?
Do you feel toxic? Have you been smoking and eating poorly for the last 4 months?
Ask yourself why and you will answer your own question.
There is zero benefit to your baby. Guarenteed.
Your baby will eat you alive. I would imagine with the amount of fasting you have been doing you don't have much to spare. And if you are put in danger then the one relying on your body will be in danger.
In short.. WHY bother? If you want to feel high smoke a joint.