Dr Claire Feeley

Abstract

Objectives 
Water immersion during labour using a birth pool to achieve relaxation and pain relief during the first and possibly part of the second stage of labour is an increasingly popular care option in several countries. It is used particularly by healthy women who experience a straightforward pregnancy, labour spontaneously at term gestation and plan to give birth in a midwifery led care setting. More women are also choosing to give birth in water. There is debate about the safety of intrapartum water immersion, particularly waterbirth. We synthesised the evidence that compared the effect of water immersion during labour or waterbirth on intrapartum interventions and outcomes to standard care with no water immersion. A secondary objective was to synthesise data relating to clinical care practices and birth settings that women experience who immerse in water and women who do not.

Design 
Systematic review and meta-analysis.

Data sources 
A search was conducted using CINAHL, Medline, Embase, BioMed Central and PsycINFO during March 2020 and was replicated in May 2021.

Eligibility criteria for selecting studies 
Primary quantitative studies published in 2000 or later, examining maternal or neonatal interventions and outcomes using the birthing pool for labour and/or birth.

Data extraction and synthesis 
Full-text screening was undertaken independently against inclusion/exclusion criteria in two pairs. Risk of bias assessment included review of seven domains based on the Robbins-I Risk of Bias Tool. All outcomes were summarised using an OR and 95% CI. All calculations were conducted in Comprehensive Meta-Analysis V.3, using the inverse variance method. Results of individual studies were converted to log OR and SE for synthesis. Fixed effects models were used when I2 was less than 50%, otherwise random effects models were used. The fail-safe N estimates were calculated to determine the number of studies necessary to change the estimates. Begg’s test and Egger’s regression risk assessed risk of bias across studies. Trim-and-fill analysis was used to estimate the magnitude of effect of the bias. Meta-regression was completed when at least 10 studies provided data for an outcome.

Results 
We included 36 studies in the review, (N=157 546 participants). Thirty-one studies were conducted in an obstetric unit setting (n=70 393), four studies were conducted in midwife led settings (n=61 385) and one study was a mixed setting (OU and homebirth) (n=25 768). Midwife led settings included planned home and freestanding midwifery unit (k=1), alongside midwifery units (k=1), planned homebirth (k=1), a freestanding midwifery unit and an alongside midwifery unit (k=1) and an alongside midwifery unit (k=1). For water immersion, 25 studies involved women who planned to have/had a waterbirth (n=151 742), seven involved water immersion for labour only (1901), three studies reported on water immersion during labour and waterbirth (n=3688) and one study was unclear about the timing of water immersion (n=215).

Water immersion significantly reduced use of epidural (k=7, n=10 993; OR 0.17 95% CI 0.05 to 0.56), injected opioids (k=8, n=27 391; OR 0.22 95% CI 0.13 to 0.38), episiotomy (k=15, n=36 558; OR 0.16; 95% CI 0.10 to 0.27), maternal pain (k=8, n=1200; OR 0.24 95% CI 0.12 to 0.51) and postpartum haemorrhage (k=15, n=63 891; OR 0.69 95% CI 0.51 to 0.95). There was an increase in maternal satisfaction (k=6, n=4144; OR 1.95 95% CI 1.28 to 2.96) and odds of an intact perineum (k=17, n=59 070; OR 1.48; 95% CI 1.21 to 1.79) with water immersion. Waterbirth was associated with increased odds of cord avulsion (OR 1.94 95% CI 1.30 to 2.88), although the absolute risk remained low (4.3 per 1000 vs 1.3 per 1000). There were no differences in any other identified neonatal outcomes.

Conclusions 
​​​​​​​This review endorses previous reviews showing clear benefits resulting from intrapartum water immersion for healthy women and their newborns. While most included studies were conducted in obstetric units, to enable the identification of best practice regarding water immersion, future birthing pool research should integrate factors that are known to influence intrapartum interventions and outcomes. These include maternal parity, the care model, care practices and birth setting.

Abstract

Aims: To gather, quality assess, synthesize and interpret the views, feeling, and experiences of women who used water immersion during labour and/or birth.

Design: A systematic meta-thematic synthesis and GRADE-CERQual.

Data sources: We searched MEDLINE, CINHAL, PsychINFO, AMED, EMBASE (MIDIRS only), LILACS, AJOL. Additional searches were carried out using Ethos (thesis database), cross-referencing against Google Scholar and citation chasing. Searches were carried out in August 2019, updated February 2020.

Methods: Studies that met the selection criteria were appraised for quality. Data were extracted from the studies using meta-thematic analytical techniques; coding, descriptive findings, and analytical findings. The descriptive findings were subjected to confidence assessments using GRADE-CERQual.

Results: Seven studies met the inclusion criteria. Nine key statements of findings were generated - one had high confidence, three moderate, three low and one very low confidence in the findings. The analytical findings generated three main themes: Liberation and Self-Emancipation, Synergy, transcendence and demarcation and Transformative birth and beyond. Overall, women experienced warm water immersion during labour and/or birth positively. Both the water and pool itself, facilitated women's physical and psychological needs during labour and/or birth, including offering effective analgesia. Our findings indicated that birthing pools are versatile tools that provide for a space that women can adapt and influence to best suit their individual needs.

Conclusion: Women who used warm water immersion for labour and/or birth describe liberating and transformative experiences of welcoming their babies into the world. They were empowered, liberated, and satisfied. We recommend maternity professionals and services offer water immersion as a standard method of pain relief during labour/birth.

Impact: Understanding women's experiences of labour and birth will inform future clinical practice. Midwives are optimally positioned to enhance women's access to water immersion. These findings have implications for education, guideline, and policy development as well as clinical practice.

Keywords: analgesia; birth pool; childbirth; maternity care; midwifery; nursing; pain relief; water.