A recent Cochrane review of 11 randomized trials evaluated the safety and efficacy of water immersion during the first stage of labor. The trials, conducted in Europe, Australia, North and South America, and Africa, involved a total of 3,146 low risk women.

Water immersion, which involves complete abdominal submersion in a bath or pool, reduced both maternal pain and epidural and spinal analgesia requirements. Analgesia/anesthesia use was significantly lower for immersion groups compared to controls in a meta-analysis of 6 trials with 2,499 women (38.1% vs. 42.1%, p = 0.025, Number Needed to Treat (NNT) = 25). These data met DynaMed’s criteria for Level 1 “likely reliable” evidence.

One high quality trial with 120 women found that significantly fewer women in the immersion group experienced moderate to severe pain (67.8% vs. 90.2%, p = 0.004, Number Needed to Treat (NNT) = 5). There were no significant differences in labor duration, operative delivery rates, or neonatal outcomes (Cochrane Database Syst Rev 2009 Apr 15;(2):CD000111).

In an analysis of 7 of the trials representing 2,628 women, there were no significant differences between the immersion versus no immersion groups in the need for assisted vaginal delivery (11.9% vs. 13.8%).

Analysis of 8 of the studies, involving 2,712 women showed no significant differences in cesarean section rates (5.3% vs. 4.3%) or neonatal outcomes (Apgar < 7 at 5 minutes, neonatal units admissions, neonatal infections rates).

So far, there have been no published trials evaluating effects of water immersion during third stage of labor, or studies comparing different types of immersion baths/pools.

This article was adapted from the DynaMed Weekly Update – Volume 4 Issue 21, May 26, 2009. DynaMed, published by EBSCO Publishing (www.ebscohost.com) is a commercial-free clinical reference tool created by physicians for physicians and other health care professionals for use primarily at the ‘point-of-care.’ Offering clinically-organized summaries for more than 3,000 topics, DynaMed is updated daily and monitors an extensive collection of journals and evidence review sources (www.ebscohost.com/dynamed/sources.php). New evidence is integrated with existing content, and overall conclusions updated based on the best available evidence.

For more information on using water immersion in labor, see the Overview of labor and delivery topic in the DynaMed database. Also see the article, “Water Births Expected to Make Big Splash in Coming Decade”.