The method by which the process of labour began, or delivery by caesarian section occurred.

National Codes:

1	Spontaneous; the onset of regular contractions whether or not preceded by spontaneous rupture of the membranes
2	Any caesarean section carried out before the onset of labour or a planned elective caesarean section carried out immediately following the onset of labour, when the decision was made before labour
3	Surgical induction; by amniotomy
4	Medical induction; including administration of agents either orally, intravenously or intravaginally with the intention of initiating labour
5	Combination of surgical induction and medical induction

Note: 1 is not to be recorded if a planned elective caesarean section is carried out, see 2. If an unplanned caesarean section is performed after labour has started code 1, 3, 4, & 5 is to be used as applicable. If the methods at 3, 4, or 5 have been used to accelerate rather than induce labour, they should not be recorded under these codes. 

This attribute is also known by these names:

Context	Alias
plural	LABOUR OR DELIVERY ONSET METHODS