Introducing new babies to water: the risks of chlorinated swimming pools and the benefits of home tubs

In the UK, parents do not need to wait until their babies have completed their immunization. The NHS gives the go ahead for babies to go swimming before vaccinations that generally start at two months (1). This has triggered a competitive streak about how early is early for baby swimming. The winner so far is a one-day old baby, going to his baby swimming instructor dad’s pool exactly 31 hours and 46 minutes after his delivery by Cesarean section in the local hospital (2).  In the feature, images show happy bonding, excitement and dad’s confidence. This lively little guy takes it all in his stride and is very interactive, as newborns can be even if they are still close-sighted and cannot hear until the amniotic fluid has completely drained from their inner ear. One could argue that it’s like an aquatic ‘skin to skin’, which has been shown to have a range of benefits for new babies held against their mums’ or dads’ chests soon after birth. For women who have c-sections or difficult births, the recommendation is to wait until they have had their six-week check, hence the benefit of their partners introducing the newborns to water earlier.

Having taken my first born to swim in a large, little heated and noisy municipal pool aged three weeks, I can recall my swimmer’s urge to share the joy of being in water with my baby, as well as the exhilarating need to reassure myself that everything is possible with a baby. Now, as a grandmother, I have a little more of the old fox’s cautions and think that cubs really need to be protected from the wide world in the weeks following birth. No, taking a baby younger than two weeks old to a busy chlorinated pool is definitely not commendable. There are good reasons to wait a little longer and choose alternative options for stimulating bathing. There are two main inter-related factors to consider: the physiology of newborns and the by-products of chlorine in heated indoor pools.

Delaying the first bath is now recommended, why?

Until recently, newborns were whisked away to be washed and most of them were given a bath within the next 24 hours. Following recent research on vernix caseosa, the thick white cheese-like substance that covers babies’ skin at birth, the advice is now to allow this coating to be absorbed rather than being removed, as this confers immunity advantages. As babies get ready to be born, pulmonary surfactant produced by the maturing fetal lungs increases in the amniotic fluid. The mixture or vernix and amniotic fluid swallowed by the fetus has been found to have strong anti-microbial properties and to inhibit the growth of common perinatal pathogens such as B. streptococcus and E. coli. The natural protection conferred by the vernix on babies’ skins particularly important for pre-term babies -who, interestingly, are usually born with a thicker coating than babies born at or after 40 weeks.

Dr Amy Myers has recently made a plea for routine newborn baths to be delayed for 24 hours or ideally 48 hours, whether in hospital or at home (3). In addition to the vernix argument, she explains that there is a risk of a drop in blood sugar for newborns due not so much to getting cold as to the release of stress hormones caused by intense new experiences, even exciting and enjoyable ones. Babies may then become too sleepy to feed and risk an even lower blood sugar level, resulting in neonatal hypoglycemia. 8.5% of newborns bathed early in the study she conducted suffered from low blood sugar, but this was reduced by 4% if the bath was delayed 12 hours. The World Health Organisation recognizes this risk and recommends delaying the first bath for 24 hours to keep babies warm, ideally close to a parent’s body that constitutes a natural thermostat (4). Dr Myers’ main finding was that delayed newborn bathing resulted in an increase in breastfeeding initiation rates. The initiation of breastfeeding in the first week is a complex process and the less external irritants mother and baby are exposed to, the better (5).

Does umbilical cord care matter?

Birthlight Aquatic Nurture for Newborns Course

Baby bath with a difference … by Francoise Freedman

Until recently, submerging the cord stump before babies’ cords had fallen off, roughly 10 days after birth, was a matter of controversy. New mums were shown the art of ‘top and tail bathing’ in shallow baby baths or in kitchen sinks. Deeper baths were only advised after the cord had fallen off. This advice holds worldwide across cultures, one among very few practices around childbirth that seems to be a universal human hallmark. Yet in the last generation we have broken with traditions prevailing since the dawn of humanity not just with reproductive technologies but by crossing ancient cultural boundaries upheld by most peoples:  we have innovated with water birth, lotus birth (no clamping of the cord until it falls off spontaneously), eating our placentas and… newborn baby swimming. Research studies show conflicting results (cord separating earlier if baths are avoided in the first ten days (6)) but this is shown not to be the case in an authoritative controlled study showing that ‘Tub bathing is a safe and pleasurable alternative to sponge bathing in healthy, term newborns’. Moreover positive thermo-regulating effects of early warm baths on babies born before full term (8)). Yet the cord stump is a sensitive area where new tissue is forming, prone to inflammation and granulation. Over 50% of babies are prone to infections. While bath water might not be an issue, treated pool water might cause the absorption of toxic substances, such as by-products of chlorine, through the cord stump.

Newborns’ delicate skins

The skin of the newborn serves a pivotal role in the transition from the aqueous intrauterine environment to extra-uterine terrestrial life and is integral to the vital functions of mechanical protection, thermoregulation, cutaneous immune-surveillance, and maintenance of a barrier that prevents insensible loss of body fluids. We know from research that infant skin is in a developmental stage structurally up to 3 months of age. Even chubby babies’ skin is thin – it is three to five times thinner than an adult’s skin – and very permeable. It has fewer elastic fibres than adult skin and the epidermis is made up of smaller cells, which increases the absorption of water and other substances into the body. Furthermore, the surface area of a baby’s skin is far greater than an adult relative to body weight.  The skin can absorb irritants, allergens and bacteria from the environment. Therefore, a substance that penetrates a baby’s skin will end up being considerably more concentrated than in an adult’s body.

The by-products of chlorine

Chlorination, sometimes in conjunction with other technologies, is by far the most widely used means of disinfection for pools worldwide. It is supported by the World Health Organization (WHO) and other bodies such as the US National Swimming Pool Federation and CDC. The UK Pool Water Treatment Advisory Group has set guidelines for pool management and disinfection to ensure that people can gain the health benefits of swimming in safety. Minimum levels of active chlorine must be present, often by law, to ensure effective disinfection to prevent transmission of infection. As regards disinfection by-products, WHO considers that “the risks from exposure to chlorination by-products in reasonably well managed swimming pools would be considered small and must be set against benefits of aerobic exercise and risks in the absence of disinfection”. But these risks are evaluated for children and adults, not for young babies.

Retrospective research on the possible harmful effects of chlorine in pools on infants has established risk factors rather than conclusive causal links, due to confounding factors in children’s genetic make-up and lives, but these risks are real and cannot be ignored. When chlorine destroys contaminants in pool water, it creates harmful disinfection byproducts (DBPs). These are formed when the chlorine in a pool reacts with organic matter such as skin or hair. Other by-products of chlorine are volatile chloramines and trihalomethanes. DBPs cause irritation to eyes, skin and mostly to the tissues of the bronchiae and lungs. While babies’ immune systems are developing through exposure to their environments, DBPs can have adverse effects but these have not yet been investigated. A main effect of DBPs, sometimes interpreted as “chlorine allergy” is “irritant dermatitis” causing the skin to become irritated and producing itchy and dry skin, bloodshot and burning eyes, dry hair and overall discomfort. This is not really an allergy but more something like a chemical burn), caused by hypersensitivity to this irritant. (10)

All researchers call for more studies on the effects of chlorine products on the respiratory tract of babies and very young children, as the three major studies indicate that children who swam in chlorinated pools in infancy have an increased risk of allergic sensitization and asthma through to adulthood. Chlorine by-products, particularly chloramines, irritate and sensitize the respiratory tract and can be particularly damaging to infants’ lungs, which are still developing. Prospective longitudinal studies are needed to characterize and confirm an association between chlorinated pools and outcome in allergic and respiratory diseases as children grow up. Parents need to be aware that these risks are likely to affect a significant ratio of baby swimmers. But we take lots of risks as parents and our homes and the world is increasingly polluted with irritant substances. Now, we all want to reduce risks too.  Does taking babies very early to chlorinated pools, before their skin has had time to thicken and mature, increase risks? There is no research available (yet) but based on physiology and common sense reasoning, the answer is probably yes.

Benefits versus risks

Do benefits of bonding, most specially with dads, the excitement of an activity that is socially highly rated among new parents outweigh the possible health risks of chlorine by-products? There may be cautions and compromises that help lower risks of taking babies to local pools after their cord has fallen, which may be a safe initial threshold to give new babies the best possible foundations for immunity. Parents can be pro-active and ask about the levels of chlorine in the pools where they intend to take their new babies. WHO considers that adequate disinfection can generally be achieved with around 1 ppm (mg/l) free available chlorine in the pool though up to 2 –3 ppm may be needed in hot tubs because of higher temperatures. Regulations in Europe generally set an FAC range for pools between 0.4 ppm and 1.4 ppm. WHO considers that combined chlorine (mainly chloramine by-products), in the pool water should be kept below half the FAC level to maintain bather comfort, notably freedom from eye irritation. As regards chloramines in the air, WHO has set a provisional guideline value of 0.5 mg/m3 expressed as trichloramine. (11)

Good ventilation can be the most important aspect of pool management regarding the use of chlorine in warm pools. A constant inflow of outside air, appropriately warm, can help dissipate the potentially harmful chlorine by-products.

The filtration system is also important to ensure rapid turnover in the pool so that fresh water remains constant. Old systems may not offer this guarantee. (12)

The hygiene facilities also need to be considered. Are the showers warm enough to encourage bathers to wash before swimming and rinse afterwards? Are there baby-friendly facilities?
Even if the pool water and air temperatures are suitable, changing rooms can be draughty places in some UK pools. Many babies dislike showers. Some pools provide baby baths that are more effective and pleasant to rinse off chorine from very small babies’ bodies right after baby swimming rather than back home.

Alternative forms of water treatment are limited but pools that use them are worth considering for parents of infants who may be more sensitive to chlorine than average. Saltwater system pools are not chlorine free but use lower levels of chlorine. A salt cell, which is contained in the filtration equipment, changes salt to chlorine by a form of electrolysis. This naturally generated chlorine goes right to work in the filtering system and is partially converted back to salt before it returns to the pool. (13)  Many people with chlorine sensitivities can tolerate these lower levels of chlorine, which is one reason why salt-cell pools have grown in popularity in the last decades. The newer ozone filters—are becoming more common in spas and pools. Ozone-filtered water is clean and very baby-friendly. Concerned parents with sensitive infants can try to find a pool with an ozone filter, which can sanitize water without producing chlorinated by-products. Regulations however raise costs and complicate the management of ozone treated pools, which is why not more baby-friendly pools in the UK are ozone treated.

Home tub options for the early weeks

Unless the social draw of the pool proves irresistible and the teacher’s skills make the experience so worthwhile that risks are counter-weighed by all the endorphins generated in sessions for new babies in your local pool, why not consider a home tub? If there is a history of asthma or other respiratory illness in the family, this may be a choice you make to protect your baby in the delicate growing first couple of months.

If you do not have a bathtub at home, inflatable birthing pools or paddling pools are relatively cheap and can fit even in small flats. They provide a facility for a family bath with one or two parents and/or siblings. The bath can be an intimate or a more social occasion with the sounds, visual stimuli, scents and feel of home for the baby. Feeding can be done in the bath. There are reduced risks of temperature loss or overheating through moving the baby around, dressing and undressing. While parents (and siblings) are seated in the home tub, the first gentle moves can be tried slowly once the baby starts relaxing and showing signs of enjoying being in warm water. The water needs to be changed every two days. The costs involved are manageable for most families. There are new water treatments such as Grander water technology, using a minimum of chemical additives. (14)

Considerations of early immunity are increasingly important for adult health. The more is discovered about the microbiome, the more it seems that we need to give priority to natural means of consolidating babies’ immunity. The brave new age of breaking boundaries and records with babies may be over. Newborn babies’ physiology is orchestrated in very complex ways: more inter-relations are being discovered each year. The awareness that irritants such as chlorine might be harmful later in our children’s adult lives opens a space of greater responsibility for parents in the early weeks.

Birthlight Aquatic Nurture for Newborns Course

Baby bath with a difference … by Francoise Freedman


2.  2014.


6.  Tulay Ayyildiz et al. 2015. The Effects of Two Bathing Methods on the Time of Separation of Umbilical Cord in Term Babies in Turkey. Iran Red Crescent Med J. 2015 Jan; 17(1): e19053.

7. Bryanton et al, J. J Obstet Gynecol Neonatal Nurs. 2004 Nov-Dec;33(6):704-12. Tub bathing versus traditional sponge bathing for the newborn.

8. Loring, C et al. Tub bathing improves thermoregulation of the late preterm infant
J Obstet Gynecol Neonatal Nurs. 2012 Mar;41(2):171-9.

 9. A Bernard et al. 2007. Infant Swimming Practice, Pulmonary Epithelium Integrity, and the Risk of Allergic and Respiratory Diseases Later in Childhood. Pediatrics · June 2007, VOLUME 119 / ISSUE 6.
Wiesel, C.P et al. Childhood Asthma and Environmental Exposures at Swimming Pools: State of the Science and Research Recommendations. Environ Health Perspect. 2009 Apr; 117(4): 500–507. Published online 2008 Sep 30. doi:  10.1289/ehp.11513
C Voisin, A Sardella, F Marcucci, A Bernard European Respiratory Journal 2010 36: 41-47; DOI: 10.1183/09031936.00118009. Summary & Comment in Pediatrics October 2011, VOLUME 128 / ISSUE Supplement 3


11. (Pool Management Guidelines:

12. The turnover rate in the thoughtfully built Swimworks pools in Rugby and Leamington are under 45 mins, meaning constant fresh water. The Pool Water Treatment Advisory Group (PWTAG) advise
high turnover rates  in their 2017 Code of Practice but of course this is only possible in newly built pools (Christian and Jo Wilson, personal communication).