Can you fly during pregnancy?

It's advised not to.. EasyJet's policy on the matter is this.. "expectant mothers Expectant mothers can be accepted for travel up to 27 weeks (inclusive) without a medical certificate. When travelling between 28 - 35 (inclusive) weeks a medical certificate confirming the number of weeks of pregnancy is required confirming that the passenger is fit to fly. Pregnant passengers cannot be accepted for travel on or after week 36, and therefore all return flights must be completed no later than week 36. All medical certification must be supplied by a doctor - medical certificates completed by a registered midwife cannot be accepted. Conditions of Carriage Article 8.2." With thanks.