Being pregnant is a great thing, but it does mean that you have to be twice as responsible and conscious of your general well being. It also means that when traveling there are certain things you have to be more conscious of and adherent to.

Traveling Without First Speaking to Your Doctor
For obvious reasons, it is important to discuss your travel plans with your doctor before booking your flight. Depending on the nature of your pregnancy, pregnant women are most commonly advised by their doctors to travel in the second trimester of their pregnancy because by this time morning sickness would have been over, energy levels would be higher and the chances of miscarriage would be low. Additionally, a doctor can refer you to an obstetrician or midwife at your destination in case you need medical attention while there.

Sitting Down on the Same Spot for a Long While During Long-Haul Flights
Taking breaks from sitting on your seat, moving around from time to time with strolls up and down the cabin or with simple stretches, is the best way for pregnant women to avoid aches and reduce their risk of developing DVT (Deep Vein Thrombosis). It's really a great way to keep your circulation flowing.

Not Bringing Water Along With You
Dehydration can be a serious problem for pregnant women and the fact is that airlines might not be able to provide you with the quantity of water you need as a pregnant woman. This is why you should not hide the fact that you are pregnant from airline personnel, you should let them know so they can accord you necessary privileges. You should, therefore, endeavour to bring as much water as you would need along with you.

Traveling Without Checking Airline Restrictions
This is mainly to avoid harassments and delays while boarding. Different airlines have different rules about traveling while pregnant, but most will ask for an official confirmation that you're fit, well and won't go into labour when you're over 28 weeks. However, there is no real way for airlines to know your number of weeks except by a letter from your doctor. This is why when you're noticeably pregnant, it is best to start carrying this letter to confirm your number of weeks and avoid unnecessarily delays while boarding.