Labour is when regular contractions lead to opening up of the cervix (neck of the womb). This normally occurs at between 37 and 42 weeks of pregnancy. If it occurs before 37 weeks, it is known as premature labour.
In the UK, having a baby early is common: eight in 100 babies are born before 37 weeks. Very premature birth is much less common, with fewer than one in 100 babies being born at between 22 and 28 weeks of pregnancy.
This information has been developed by the RCOG Patient Information Committee and is based on various RCOG guidelines, RCOG Scientific impact papers, journal articals and research studies which are all referenced in the patient information leaflet.