This preview shows page 1. Sign up to view the full content.
Unformatted text preview: ncision
at the midline directed obliquely away from the rectum.17
The response variable, laceration, is coded on a fivepoint ordinal scale, classified as ‘1°’ (least severe) to ‘4°’
(most severe), the classification based on the amount of
tissue damage involvement, and a fifth group consisting
of women free of any laceration.17,18 For the purpose of
this paper, we will restrict our analysis to midline episiotomy, coded as ‘0’ indicating the absence of midline
episiotomy and ‘1’ if the procedure was performed.
The proportional odds (PO) and continuation-ratio
(CR) models (models 2 and 4, respectively) were fit to
the data described in Table 3, and their results
summarized in Table 4. Midline episiotomy carried
with it a relative risk of 2.1 (95% CI : 1.8–2.5) compared to no episiotomy for ‘any laceration’ by the PO
model, and a relative risk of 1.4 (95% CI : 1.3–1.5) by
the CR model. It is important to note that the assumptions of the underlying models differ: the PO model
View Full Document
This document was uploaded on 02/25/2014.
- Spring '11