Background: The literature is tentative in establishing links between birth position and perineal outcome. Evidence is inconclusive about risks and benefits of women's options for birth position. The objective of this study was to gain further evidence to inform perinatal caregivers about the effect of birth position on perineal outcome, and to assist birth attendants in providing women with information and opportunities for minimizing perineal trauma.
Methods: Data from 2891 normal vaginal births were analyzed. Descriptive statistics were obtained for variables of interest, and cross-tabulations were generated to explore possible relationships between perineal outcomes, birth positions, and accoucheur type. Logistic regression models were used to examine potential confounding and interaction effects of relevant variables.
Results: Multiple regression analysis revealed a statistically significant association between birth position and perineal outcome. Overall, the lateral position was associated with the highest rate of intact perineum (66.6%) and the most favorable perineal outcome profile. The squatting position was associated with the least favorable perineal outcomes (intact rate 42%), especially for primiparas. A statistically significant association was demonstrated between perineal outcome and accoucheur type. The obstetrician group generated an episiotomy rate of 26 percent, which was more than five times higher than episiotomy rates for all midwife categories. The rate for tear requiring suture of 42.1 percent for the obstetric category was 5 to 7 percentage points higher than that for midwives. Intact perineum was achieved for 31.9 percent of women delivered by obstetricians compared with 56 to 61 percent for three midwifery categories.
Conclusion: Findings contribute to growing evidence that birth position may affect perineal outcome. Women's childbirth experiences should reflect decisions made in partnership with midwives and obstetricians who are equipped with knowledge of risks and benefits of birthing options and skills to implement women's choices for birth. Further identification and recognition of the strategies used by midwives to achieve favorable perineal outcomes is warranted.