Induction of labour in normal pregnancies at or beyond term

A normal pregnancy lasts about 40 weeks from the start of the woman's last menstrual period, but anything from 37 to 42 weeks is considered within the normal range. Births before 37 weeks are considered premature because these babies often have breathing difficulties and other problems as some of their organs will not yet be fully matured, e.g. their livers. Births after 42 weeks seem to carry a slightly increased risk for the baby, and this review sought to find out if induction of labour at a prespecified time could reduce this increased risk or not. There are currently no tests that can tell if a baby would be better to be left in the womb or be induced and born, so arbitrary time limits have been suggested. The review of trials found 19 studies involving almost 8000 women given induction of labour at various times from 38 weeks to over 42 weeks' gestation; some were quite old trials and the quality was variable. The review grouped the trials by induction at (1) 37 to 40 weeks; (2) 41 completed weeks; and (3) 42 completed weeks, compared with waiting to a later date. There were fewer baby deaths when a labour induction policy was implemented after 41 completed weeks or later. However, such deaths were rare with either policy. Women's experiences and opinions about these choices have not been adequately evaluated.