Nothing you can do now. When you get medicals you have two options : complete everything including the x-ray part or do all the others excluding x-ray. It depends on you and what your doctor says, ask for medical opionion on that.
If you are going to complete the whole medicals with x-rays ....let the examining doctor know you are pregnant. You can only add new born after delivery , so nothing much you can do.
If however you prefer not to do the x-ray part, once you get medicals, submit a webform and also write a letter directly to Accra that you are pregnant and won't be completing the x-ray part of the medicals , submit evidence of your pregnancy with the mail. Do the other parts, submit it, your medicals won't be completed and the processing won't move forward yet.once you deliver, do the x-ray part, inform Accra that you have a newborn and they will send you another forms to fill, the processing will continue from there .