Main results
Our study found that babies born to women who utilised the birthing pool
for WWI or waterbirth, despite some moderate risk factors, had lower
rates of admission to the NNU and lower rates of observation for a
suspected infectious condition and antibiotic administration.
Encouragingly, this adds to existing evidence that WWI/Waterbirth is not
associated with increased rates of NNU admission in low-risk women(6, 8). No babies required NNU admission for water
inhalation or drowning.
The risk of neonatal sepsis is often cited by those who oppose
WWI/Waterbirth (15). However, case reports of neonates
infected with L. pneumophila and P. aeruginosa(16), appear to have resulted from a deviation from
established waterbirth protocols and the use of unclean water.
Overwhelmingly, recent literature suggests no increase in infective
sequalae from WWI/WB, which is consistent with our findings(17, 18).
Most women (95.5%) who were febrile intrapartum had an epidural, likely
explaining the favourable results for the WWI/WB group. This association
between maternal pyrexia and epidurals is well established with one
retrospective study of 261,457 women finding those with an epidural five
times more likely to experience pyrexia and neonates 1.6 times more
likely to receive antibiotics (19). The multivariate
regression analysis removed women with epidurals from the cohort and
subsequently showed no differences in NNU admission between the groups.
The role of waterbirth as a contributor to rates of perineal trauma is
controversial. Our study showed similar rates of OASIS between land
birth and WWI/WB. However, the subgroup analysis comparing spontaneous
vaginal birth in women on land and in water, showed a significant
association between land birth and increased rates of episiotomy. This
land birth group did not include women who used WWI during labour and
then birthed on land. A Cochrane review (6), and
several recent studies (20), support the notion that
WWI/WB does not increase rates of perineal trauma and our findings are
consistent with this.
Our study suggested lower rates of PPH in the WWI/Waterbirth group,
however estimating blood loss is notoriously inaccurate(21), and more challenging in water. The waterbirth
protocol within the study site recommends placental delivery occurs on
land, thereby allowing blood loss to be more accurately estimated. The
authors recognise that ‘pool exit’ is not always immediate and hence
estimations of blood loss in the waterbirth group are more likely to be
imprecise. Neiman (18) suggests a small increase in
PPH with waterbirth, but this is inconsistent with the broader
literature (6, 20, 22), which concur no clinical
difference between groups.
Cord avulsion occurs when rapid cord traction overstretches umbilical
cords that cannot reach above the water surface (23).
This is a rare event and studies are inevitably underpowered to prove a
statistically significant association with waterbirth. According to
Schafer (23), based on pooled data of 10,000
waterbirths, the incidence of cord avulsion appears increased at
approximately 3.10 per 1000. However, this risk can be mitigated by
clear waterbirth protocols, midwifery education and discussion with
women before pool entry (20, 23).