I went to Japan at 2x week last time when I had my first baby. It 's the most stable period and should be okay. Just that you need to be careful in choosing food. Also, better choose places that has good medical care and collect information on emergency numbers and clinic/hospial addresses in advance in case something happens. Further, when planning your itenerary, don't forget to put in a lot of short breaks as you will feel tired much easier than usual. Wish you have a good trip.