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Group B strep and water birth (query bank)

Published: 30/11/2011


Is waterbirth associated with an increased risk of early-onset neontal group B streptococcal infection in babies born to women with known group B strep?


Very little data regarding water births by women with known GBS were identified:

One prospective study including 213 women who delivered in water and a control group of 261 who spent the first stage of labour in water but delivered in a traditional birth environment was reported by Zanetti-Dallenbach et al(2007). This found that:

“The numbers of GBS carriers were equally distributed between the two groups. Although the rate of water contamination was significantly higher in the study than in the control group (P< 0.001), the neonates born in water were less frequently colonized with GBS than those born in a traditional environment, even when preterm rupture of membranes occurred (nasal swabs, P=0.005; pharyngeal swabs, P=0.024)”.

An earlier publication by Zanetti-Dallenbach et al (2006) included 89 women with a water birth compared with 133 women who delivered in a bed following immersion in water. There was no statistical difference in the number of GBS-carriers or of GBS-colonized neonates between the two groups. “The results even showed a trend towards less GBS colonization of the newborn after a waterbirth.”

One case of an infant (born at home in a bathtub) who was admitted at 4 days of age with group B streptococcal meningitis is briefly reported by Bowden et al.

(Evidence level III)

An article published by Cohain considers the studies included in a Cochrane review of immersion in water in labour and birth. (Cluett et al). The Cochrane review concluded that “The safety regarding infection and neonatal outcomes are not addressed, and large collaborative trials are needed to answer these critical issues.” Cohain notes that “The literature provides a single case of early onset newborn Group B Strep (GBS) among 4432 waterbirths, suggesting that low-risk women who give birth in water may have a far lower rate of newborn GBS than women who have a dry birth. The last reported rate of newborn GBS for dry births was 1 in 1450.”

Considering water birth in general, the 2006 Joint statement from the RCOG and the Royal College of Midwives “Immersion in Water During Labour and Birth”, whilst making no specific reference to Group B strep, says that:

“All healthy women with uncomplicated pregnancies at term should have the option of water birth available to them and should be able to proceed to a water birth if they wish.”

(Evidence level IV)


  • Bowden K. Kessler D. Pinette M. Wilson E. Underwater birth: missing the evidence or missing the point?.[Erratum appears in Pediatrics. 2004 Feb 2;113(2):433] Pediatrics. 112(4):972-3, 2003 Oct. Free full text
  • Cluett ER, Burns E. Immersion in water in labour and birth. Cochrane Database of Systematic Reviews 2009, Issue 2. Art. No.: CD000111. DOI: 10.1002/14651858.CD000111.pub3. Abstract and full text (restricted in some countries). Full text available to Fellows, Members and Trainees here.
  • Cohain JS. Waterbirth and GBS. Midwifery Today with International Midwife. (96):9-10, 2010-2011 Winter. Abstract
  • RCOG and Royal College of Midwives. Immersion in Water During Labour and Birth. Joint statement no. 1. 2006.
  • Zanetti-Dallenbach R. Lapaire O. Maertens A. Frei R. Holzgreve W. Hosli I. Water birth: is the water an additional reservoir for group B streptococcus?. Archives of Gynecology & Obstetrics. 273(4):236-8, 2006 Jan. Abstract
  • Zanetti-Dallenbach RA. Holzgreve W. Hosli I. Neonatal group B streptococcus colonization in water births. International Journal of Gynaecology & Obstetrics. 98(1):54-5, 2007 Jul.

Search date

November 2011

Classification of evidence levels

  • Ia: Evidence obtained from meta-analysis of randomised controlled trials.
  • Ib: Evidence obtained from at least one randomised controlled trial.
  • IIa: Evidence obtained from at least one well-designed controlled study without randomisation.
  • IIb: Evidence obtained from at least one other type of well-designed quasi-experimental study.
  • III: Evidence obtained from well-designed non-experimental descriptive studies, such as comparative studies, correlation studies and case studies.
  • IV: Evidence obtained from expert committee reports or opinions and/or clinical experience of respected authorities.


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