Biofilms and Birth Pools


Are biofilms a health and safety risk in hospital birth pools? What can be done to minimise the risks of biofilms in hospital birth pools? Aquabirths answers these questions and more.

What is a biofilm?

Biofilms are a collection of bacteria which have clumped together in a supportive environment, which will include the regular flow or presence of water. Biofilms are everywhere, and are likely to be the reason that we have life on earth, as the ability for bacteria to join into larger groups, rather than simply floating around as planktonic lifeforms (individual bacteria cells) appears to have been vital as part of the stepping stones from single cell to complex life (1).

When bacteria clump together into biofilms, they produce chemicals which makes them harder to destroy with normal anti-bacterial chemicals, and a combination of cleaning agents and scrubbing is necessary to remove them.

Biofilms are present in most areas of our life, and are often beneficial to our bodies, including some which reside in our gut. An example of a bodily biofilm is dental plaque, which needs to be regularly removed to avoid harm, and this is an example which clearly shows how just using an anti-bacterial mouthwash isn’t enough. Scrubbing with a toothbrush is also necessary to properly remove the bio film of dental plaque.

So, while biofilms aren’t necessarily a human health hazard, some are, so understanding how to clean them is important in all hospital environments.

Biofilms in hospitals

Biofilms can be found in many areas of hospitals (and shops, and our homes), and are likely to be present everywhere there is water. They are a natural part of the planet’s environment. The time that they may become a problem is:

  • If the bacteria that is growing in the biofilm happens to be one that can cause harm to humans
  • If this harmful bacteria is able to access the human body, eg via an open wound

For this reason, hospitals have strict policies on cleanliness, and following these policies should be enough to keep everyone safe from harmful bacteria.

Biofilms and birth pools

There are three areas that biofilms can grow on birth pools:

  • Plumbing into the pool (taps and pipes to the taps)
  • The pool itself
  • The birth pool’s drainage system

Biofilms can grow in any pipe through which water runs, including if the water is clean and chlorinated. Of course, the chlorination is likely to significantly control any pathogen build up. There is nothing that needs to be considered in the birth pool that isn’t already considered in the use of fresh water elsewhere in the hospital. For instance, there is no additional risk from the birth pool water intake than there is for the water used in scrubbing up for obstetric or other surgical procedures.

Running the water for two minutes before starting to fill the pool (so with the drain open) will ensure that any loose bacteria that might be in the intake pipes or taps will be washed away. This will also safely wash away any loose bacteria around the drain.

The second area to consider is the birth pool itself. Clearly, the infection control policies which relate to the cleaning of the pool include both anti-bacterial cleaning agents, and scrubbing, which if done correctly are sufficient to ensure that the pool is clean and safe. ALWAYS ensure that any cleaning products are non-scratch. Abrasive cleaning agents must NEVER be used – including the cleaning cloth or pad, and the chemical used. Scratches on the pool caused by abrasive cleaning chemicals or cloths/pads can be harder to clean than a smooth surface, so in theory could make complete pool cleansing harder.

Finally, the drain needs to be kept clean. Birth pools should not have an overflow, as these are very hard to clean, and if the water level in the pool rises above the overflow it is theoretically possible that the water may be contaminated from this outlet.

The drainage area (plug hole) should be kept clean as per the guidelines provided by Aquabirths (2), or as defined by local hospital policies. There are a number of options to plug the waste outlet, and hospitals can choose what they feel happiest with.

A plug with a chain should never be used as the chain is very hard to thoroughly clean. Some pools have a traditional plug (without a chain) which can be removed by hand, but this means putting an arm through the water after it has been used for a birth, so long gauntlets would be recommended. Plugs do provide a seal between the birth pool and the drain, creating a strong physical barrier between the birth pool water and the drains, so some units choose this option and provide gauntlets for removal.

However, other plug options are available. The most commonly used waste option has a valve below a grated plug hole which can be opened and closed from a system that is outside of the birth pool (no gauntlets required!). To clean the waste area, close the valve and pour sanitising solution into the waste until it comes up above the plug hole, and leave it to stand per cleansing regime guidelines. Below this waste system is a waterless trap which can be removed for cleaning if required, and being waterless it is far less likely to develop biofilm matter (remember that biofilm needs water to thrive). Some other brands of birth pools use traditional U-bend traps which are a breeding ground for bacteria. These should be removed where possible. It is possible to use a traditional plug together with the valve if a physical barrier above the entire drain is preferred – but remember that a well-cleaned waste area, together with the good practice of running water for two minutes with the waste open before filling the pool – is already an excellent way to ensure that possible bacteria build up does not contaminate the pool.

Pop-up wastes are not recommended because they slow drainage in an emergency (although in the case of maternal collapse it is recommended to ADD water to the birth pool, as the buoyancy of the water helps when lifting her out). They also inhibit the flow of pool contaminants, and a prone to collect ‘debris’.

Should we be concerned about birth pools and biofilms?

Properly cleaning birth pools is vital to ensure the safety of the pool, which is exactly the same as any other area of the hospital, including “land birth” equipment, beds, etc. While biofilms require water to form and thrive, and therefore it might be incorrectly assumed that birth pools are a higher risk than other equipment, the amount of liquid required to form a biofilm is microscopic. Therefore, any spray of body fluid (from a sneeze, for instance, or a drop of blood) can support the growth of biofilm, including on stainless steel surfaces such as bed rails. And of course, all of us are walking biofilm hosts!

Therefore, birth pools do not lead to any greater risk of biofilm formation, provided that infection control procedures are undertaken – which of course is absolutely essential in all areas of the hospital, not just birth pools! And, in reality, evidence looking at the safety of birth pools versus land birth repeatedly shows that there is no increased risk of infection from using the pool. This means that birth pools can confidently be offered as an excellent form of pain relief and comfort in labour, and as with any other area of the hospital, we simply need to follow proper infection control procedures.



  • Is biofilm formation intrinsic to the origin of life?

  • Aquabirths’ Baths for Labour and Birth Cleaning Guidance (link)