BACKGROUND:
Pain during childbirth is a concern for most pregnant women. Health care providers must know the effects of different pain relief methods to inform women in decisión making.

OBJECTIVES:
The aim of this study is to investigate the effects on maternal and neonatal outcomes of two analgesic methods frequently used during labor: water immersion and epidural analgesia.

METHODS:
In this retrospective observational cohort study of ten years (2009-2019) at a first-level hospital, in Spain, 1134 women, low-risk singleton and at term pregnancy, were selected. Among them, 567 women used water immersion; 567 women used epidural analgesia for pain control. Mode of birth and perineum condition were determined as maternal outcomes. Neonatal outcomes included 5 min Apgar score, umbilical cord arterial pH, and Neonatal Intensive Care Unit admissions. Chi-square tests and Mann-Whitney U tests, together with their effect sizes (Cramer's V, odds ratio, and Cohen's d) were used to test the main hypotheses

RESULTS:
The water immersion group was nearly 17 times more likely to achieve a spontaneous vaginal delivery (OR = 16.866 [6.540, 43.480], p < 0.001) and twice as likely to have an intact perineum (OR = 2.606 [1.290, 5.250], p = 0.007). Newborns in this group had better 5-minute Apgar scores and cord arterial pH, as well as lower rates of NICU admission than the epidural group. The odds of having a cesarean delivery were nearly 40 times higher in the epidural group (OR = 39.346 [3.610, 429.120], p < 0.001) and having an episiotomy was more than eight times more likely than in the water immersion group (OR = 8.307 [2.800, 24.610], p < 0.001)

CONCLUSIONS:
The use of water immersion was not related with adverse outcomes and presented better results than epidural analgesia.

KEY MESSAGE:
Health care providers must know the effects this pain relief methods to inform women in decision making. Poster session 1 (Group A)