<prompt> Labour is said to be prolonged when duration of latent stage of labour crosses:12 hours18 hours20 hours36 hours  <response>: labour pattern nullipara multipara prolonged latent phase 20 hrs 14 hrs protracted active phase dilatation 1.2 cmhr 1.5 cmhr protracted descent 1 cmhr 2 cmhr arrest of dilatation 2 hr 2 hr arrest of descent 1 hr 1 hr 