Actually the best months for you to go travel is between 5-6 month. Thats what my doctor suggest when I travel and I also read many book mention that. Go to see the doctor b4 your fly and let him wrote you a letter in casr any thing happen when you travel. My doctor suggest me to wear the pressure sock on the flight but I feel a bit tight about that so I just walk every half hour around the plan. Drink lots of water.
It will be fine. If anything happen remember to go to the big hospital. Shinjikui - Tokyo University hostipal. The fee is not that high. I went back to Japan when there is SAR in hong kong and the doctor ther is very nice.
Once more time better see the doctor in Hong KOng before you fly. He will give you advise.