Swimming, Chlorine and Pregnancy

Last week we saw a flurry of articles written about the release of a study in the British Journal of Dermatology. The reason for publicity is that part of the research takes aim at an activity that pregnant women commonly engage in and its potential link to the development of asthma in the unborn child. I'm not talking about cravings, though that IS always a fun and revealing topic to delve into. At this point, my title gives it all away – swimming. So before we figuratively (and literally) jump overboard, let's take a look at this theory.

_First, this was a difficult article to find. Despite so many news articles written about it, there was literally only one article that actually cited the original abstract. Typical of research pieces, the title was not something that made the association between it and the content evident to a layperson. Posted below, the research piece starts by mentioning the ‘hygiene theory’. This is the theory that the rise in allergic disease in western societies is at least in part due to children not being exposed to a variety of microorganisms during key developmental periods. More simply put, the theory suggests that we're too clean. The proliferation of antibacterial soaps and hand sanitizers, the focus on everything in the home and office being clean, the Pregnancy, the Hygiene Hypothesis and Swimmingprolific use of antibiotics, and the reduction in the amount of time that children spend outdoors, exposed to germs and allergens, creates an environment where a developing immune system isn't properly trained. Subsequently, the immune system falsely recognizes allergens, microbes and other environmental elements as ‘bad actors’ and when exposed to them, triggers an immune response to promptly boot them off stage.

_This is only a theory and some of the most recent research has punched some holes into it. The current piece though expands on the hygiene theory and suggests that exposure to certain chemicals may play a role in the development of allergic disease. In this particular instance, researchers are focused on airborne chemicals. They have found that five specific maternal occupations are characterized by ‘high or persistent exposure to airborne chemicals.’ Additionally, they suggest that sustained exposure to chlorinated chemicals from swimming pools may also be related to the development of allergic disease.

_VOCs, including chlorinated compounds like chloramines, have long been studied and show links to a variety of health problems. This study though, has caused a stir because of the mention of chlorine and swimming. Swimming is an often recommended activity for mothers to be since it is a great way to maintain a healthy weight, and unlike many other forms of aerobic exercise, swimming allows for better overall support of the body. The British National Health Service recommends swimming for pregnant women, and the U.S. National Institute of Health has sponsored studies that show swimming has no ‘adverse reproductive outcomes’. Swimming in Lake MichiganHowever, the study we're currently focused on is one that looks less at swimming as an activity and more at the exposure to chemicals.

_In not only the occupations highlighted but also swimming in chlorinated pools, researchers have suggested there is a association between VOCs and chlorine vapor and the development of atopic disease like asthma. So with that being said, are there alternatives to chlorinated swimming pools? While you can certainly wear a asthma mask to reduce exposure to pollutants (like the Honeycomb Carbon mask I recently picked up for a friend who is pregnant with her first child), a mask isn't really an ideal device to swim with.

_A coworker of mine suggested saline or ‘salt water’ pools. Personally, I've never swum or even heard of such a thing, but after some research as well as a call to a local apartment complex that has a saline pool and another to a retailer of such pools, I found one thing that appears to be true. Saline pools aren't as free of chlorine vapor as you might think. While they do use less chlorine, they still do use chlorine to sanitize the pools. They rely upon an advanced filtration system that uses the salt in the water to produce chlorine. And like traditional swimming pools, they do require a good deal of maintenance to ensure proper pH balance and chlorine levels are maintained to keep the water sanitary.

_So what about the ocean, nature's original ‘salt water pool’? Love it. The ocean is great! Unfortunately, not all pregnant women have easy access to the ocean, not to mention some times of the year are simply too cold to go for a super brisk swim (all while pregnant nonetheless). Lakes and rivers might also be excellent alternatives, but Best Place to Swim?  Yup!again, access to these bodies of water may be limiting, as could be the weather. Still, in coastal areas or in places where weather permits, all three of these would be good alternatives to chlorinated swimming pools.

_This study isn't definitive, and like other theories, a great deal of further research is needed to more clearly define the association, its consequences and suitable alternatives. I'm not suggesting you completely jump ship and avoid chlorinated swimming pools (bad pun #2). I generally do simply because I grew up swimming in lakes, rivers and ‘cricks’ (what, up home, we define as bigger than a stream but smaller than a creek). Chlorinated pools are ubiquitous, particularly here in the U.S., and access to them is often free and convenient, but if this potential does give you cause for concern, consult with your obstetrician to find suitable exercise alternatives, or at a minimum, cut back on the frequency of swimming in them while pregnant.

_Perhaps this all gives new meaning to one of my grandmother's favorite sayings, ‘Why don't you go jump in a lake?!’ Thanks Grandma!

_The original abstract of this research piece.

_Author: K. Gilmore

2 thoughts on “Swimming, Chlorine and Pregnancy

  1. Steve April 6, 2014 / 12:08 am

    Interesting blog topic. Pregnant women do have more soft tissue and one would assume there is a higher susceptibility for dermal absorption. The skin would act like a reverse osmosis membrane and reject the byproducts of chlorine THM for example. I do not see high enough levels affecting a fetus. What I am curious about is if the chloramine gases produced from chlorine would affect fetus lung development? If you have this information I would love to see it.

    My company, Intec America Corporation, manufactures a chlorine alternative called copper ionization. http://www.Intec-America.com

  2. KevvyG April 14, 2014 / 4:20 pm

    I've spent some time digging around and can find little with regard to the effects of chloramines on fetal lung development. There have been several studies and a fairly long history on the effects of chloramines on adults. Though this substance is used as a secondary disinfection process for many public water supplies, mainly for its efficacy with regard to biofilms, the primary focus of EPA related research has been on its role in disinfecting water. With this in mind, they're mainly dealing with monochloramines. Trichloramines, which is much more commonly found in swimming pools than drinking water, can produce a wide variety of more severe breathing problems for adults. Most research though tends to focus on ingestion, particularly of monochloramines, not inhalation. The Water Research Foundation does sponsor a fair amount of research on topics related to this, so they might be a good place to start for further inquiry. http://www.waterrf.org/Pages/Index.aspx
    There was a case report published in a 1999 Teratology journal about a mother to be who inhaled chlorine bleach and ammonia fumes (the building blocks for trichloramines and chloramine gas). The timing of the exposure could indicate a link between the mother's inhalation of chloramine fumes and subsequent respiratory, renal and other problems the child had. She was near term, so the baby was delivered early due to some negative signs discovered shortly after the mother's exposure. Unfortunately, I simply cannot find much more on the topic. I think this particular aspect in the study of the effects of chloramines is, to forgive a bad pun, in its infancy.

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