[US Standard Certificate Of Birth Field 44]. This class represents an adverse event associated with the onset of labor. On the form, this is a multiple-choice question (i.e., "check all that apply"), although one of the choices is "None of the above", so if that one is chosen, there should not be any others chosen. Possible values include: Premature rupture of the membranes (prolonged, > 12 hours); Precipitous labor; Prolonged labor; None of the above.