Although most airlines won't let you fly if you're 36 weeks pregnant or more, there are no concrete restrictions on travelling during pregnancy. You will probably need some form of pre-existing medical travel insurance, since the bog-standard one you usually get is unlikely to cover any pregnancy and birth related medical care you receive overseas.
Many women avoid flying during the first twelve weeks of pregnancy anyway - if you've ever had morning sickness you may be bemused at the prospect of anyone going on holiday whilst feeling like that, but holidays aren't always the reason for travelling. The risk of miscarriage is higher during the first trimester, so putting your body under the stress and strain of flying is best avoided if possible.
If you must travel, consider doing so by train instead - if you're travelling anywhere within Europe you may be surprised to discover how well connected the continent is by rail. If you really have to fly, talk to your doctor before you go, and take the following precautions for flying during any stage of pregnancy.
If you have to fly
Ask your airline whether they'll allow you to fly at all - most do, but you don't want to fork out for a seat, only to be kept on the ground on departure day. Buy the best ticket you can afford. Business class may seem extortionate most of the time, but it is more comfortable than economy.
During your flight, wear compression stockings to ward off deep vein thrombosis and reduce leg swelling. Make sure they're fitted correctly - your pharmacist, doctor or nurse can show you how, if you don't trust the instruction videos you can find on YouTube.
Drink plenty of water - dehydration is a big risk in aeroplane cabins, and makes you feel rotten, if nothing else. Take some dried fruit to snack on and keep your blood sugar levels at a comfortable level without resorting to airline snacks or chocolate.
It's also important to get up and move around whenever you can. Stay comfortable in loose clothing, preferably made of natural material that will help keep you cool when you're hot, and warm when you're cold - cotton, hemp or silk are the most comfortable choices.
On the train
Train travel is far more civilised than flying, even, dare we say, when you're not pregnant. There are no long check-in times - Eurostar's is 30 minutes - and rail stations rarely require much trekking around, unlike the larger airports, which can take a good half hour to navigate from one end to the other.
You won't be experiencing any drastic changes in air pressure, either. The worst will be when you plummet into a tunnel at high speed, causing your ears to pop. Train air-conditioning isn't normally as fierce as on a plane, either, so dehydration won't be so much of a problem, but you should still drink plenty of water, and walk up and down regularly.
This post was written by Tristan, who is the face of the World First travel blog. He writes about global goings-on and helps keep travel-lovers up to date with breaking news and travel tips.