Risk of perineal damage is not a reason to discourage a sitting birthing position: a secondary analysis.

AIM: To examine the association between semi-sitting and sitting position at the time of birth and perineal damage amongst low-risk women in primary care. BACKGROUND: Evidence on the association between birthing positions and perineal trauma is not conclusive. Most studies did not distinguish between positions during the second stage of labour and position at the time of birth. Therefore, although birthing positions do not seem to affect the overall perineal trauma rate, an increase in trauma with upright position for birthing cannot be ruled out. METHODS: Secondary analysis was performed on data from a large trial. This trial was conducted amongst primary care midwifery practices in the Netherlands. A total of 1646 women were included who had a spontaneous, vaginal delivery. Perineal outcomes were compared between women in recumbent, semi-sitting and sitting position. Logistic regression analysis was used to examine the effects of these positions after controlling for other factors. FINDINGS: No significant differences were found in intact perineum rates between the position groups. Women in sitting position were less likely to have an episiotomy and more likely to have a perineal tear than women in recumbent position. After controlling for other factors, the odds ratios (OR) were 0.29 [95% confidence interval (CI): 0.16-0.54] and 1.83 (95% CI: 1.22-2.73) respectively. Women in semi-sitting position were more likely to have a labial tear than women in recumbent position (OR: 1.43, 95% CI: 1.00-2.04). CONCLUSION: A semi-sitting or sitting birthing position does not need to be discouraged to prevent perineal damage. Women should be encouraged to use positions that are most comfortable to them.

Increased blood loss in upright birthing positions originates from perineal damage.

OBJECTIVE: To assess whether the risk of severe blood loss is increased in semi-sitting and sitting position, and if so, to which extent blood loss from perineal damage is responsible for this finding. DESIGN: Secondary analysis of data from a large trial. SETTING: Primary care midwifery practices in the Netherlands. POPULATION: About 1646 low-risk women who had a spontaneous vaginal delivery. METHODS: Blood loss was measured using a weighing scale and measuring jug. Logistic regression analysis was used to examine the net effects of birthing position and perineal damage on blood loss greater than 500 ml. MAIN OUTCOME MEASURES: Mean total blood loss and incidence of blood loss greater than 500 ml and 1000 ml. RESULTS: Mean total blood loss and the incidence of blood loss greater than 500 ml and 1000 ml were increased in semi-sitting and sitting position. In logistic regression analysis, the interaction between birthing position and perineal damage was almost significantly associated with an increased risk of blood loss greater than 500 ml. Semi-sitting and sitting position were only significant risk factors among women with perineal damage (OR 1.30, 95% CI 1.00-1.69 and OR 2.25, 95% CI 1.37-3.71, respectively). Among women with intact perineum, no association was found. CONCLUSIONS: Semi-sitting and sitting birthing positions only lead to increased blood loss among women with perineal damage.