You have got two options here.. You can proceed with your and yours wife medical's except the X-ray, which can be done at later stage. You need to discuss this thing with your panel physician and take his suggestion. Other option is to raise CSE and inform them about your wife's pregnancy and ask them an extension for medicals. In both options your processing will be stuck at this point until your wife's delivery which is only in three months time.
I personally know a case similar to yours were the VO stopped the processing after being informed about the last stages of pregnancy (3months in this case as well). How we got to know about this, is through GCMS notes. At Medical stage it was written hold until delivery is finished. In addition it was also written " request new dependent docs if added to primary file".. Its up to you how you will go ahead. If I were you, I would go with first option, and once the delivery is done shall complete the remaining test and add new born details..