Exposure to tap water during pregnancy

Abstract

Studies of disinfection byproducts ( DBPs ) in drinking water and risk of adverse reproductive outcome have usually relied on approximate measures of exposure. Individual differences in consumption of bottled or filtered water, variability in tap water consumption at home and at work, dermal and inhalation exposure to volatile contaminants, and changes in residency during pregnancy may lead to exposure misclassification. We characterized exposures to tap water and other risk factors among 71 pregnant and 43 non -pregnant women attending public health clinics. Nearly all residences had a municipal water source, but 25% of women drank filtered or bottled water. Fifty percent of the women in our sample reported working outside the home where, on average, one third of their daily water intake took place. Pregnant women consumed more water than non -pregnant women ( 3.4 vs. 3.0 total l / day ) , especially cold tap water at home ( 1.8 vs. 1.3 l / day, 95% CI for the difference = 0.1, 0.9 ) . Patterns of showering were similar for both groups of women, but pregnant women were more likely to bathe and to bathe more frequently. The prevalence of smoking was lower among pregnant women ( 22.5% vs. 32.6% ) , as was the consumption of alcohol ( 4.2% vs. 53.5%, 95% CI for the difference = À 64.9, À 33.7 ) . Thirty -two percent of women had moved during their current pregnancy. The data reaffirm the importance of collecting individual -level data for water consumption and exposure to potential confounders to avoid misclassification bias. This study is the first to target women of low socio -economic status ( SES ) and therefore of particular interest in studies of adverse reproductive outcomes for which this group is at increased risk.

Predictors of use and consumption of public drinking water among pregnant women

“…The Tucson study, however, included men (about 40% of the subjects) and a much larger number of Hispanics, which, along with regional differences, could partly explain the difference. The average time spent showering was about 120 min/ week in our study, which is in agreement with the previous American and Italian studies (Shimokura et al, 1998;Zender et al, 2001;Barbone et al, 2002), but was about 1 h more than found in the British study (Kaur et al, 2004), which reported an average of 54 min/week. The time spent in baths (50 min/week) was about the same, however, as in the British study.…”

“…The total crude amount of cold ingested tap water (1.7 L/ day) in our study was slightly less than what was found in a previous study in the United States (Zender et al, 2001), but substantially more than an earlier US study (Shimokura et al, 1998) and more recent studies conducted in Europe (Barbone et al, 2002;Kaur et al, 2004) which all reported an average of 0.6 L/day of total ingestion. In a study of water use in Tucson, AZ in the United States, Williams et al (2001) found that Hispanics were more likely to drink bottled water and spend more time showering than non-Hispanics.…”

“…However, among the women regularly swimming, the time they spent was on average longer (2.6 h/week) in our study compared to the UK study where the majority swam for less than an hour per week. Two previous US studies (Shimokura et al, 1998;Zender et al, 2001) reported less frequent use of a pool (25% and 8% of the study subjects, respectively), whereas in a study by Lynberg et al (2001), also conducted in the United States, 58% of the participants reported use of a pool. Our study has several strengths including collecting water information during, instead of after, the pregnancy, minimizing the risk for recall bias.…”

“…Use of vitamins and abstinence from smoking, alcohol, or illicit drugs were also associated with use of filtered water, which is likely linked to sociodemographic differences but nevertheless reflected a pattern that could be of importance in epidemiologic studies. Previous studies of patterns of tap water consumption and use have raised concern that the large variation found between subgroups of women could bias the results of epidemiological studies (Shimokura et al, 1998;Zender et However, few previous studies have explored the associations between individual characteristics and water-related activities in detail. Earlier studies on water consumption performed in the UK found that differences between regions and socioeconomic classes were relatively small, in general about 10% (Nieuwenhuijsen et al, 2000b).…”

“…In a Canadian study, King et al (2004) evaluated individual water-use behavior from ingestion, showering, and bathing in relation to the total exposure to trihalomethanes and Kaur et al (2004) studied tap-water-related activities in the UK. Zender et al (2001) compared the water use between pregnant and non-pregnant women in a low socioeconomic population in the United States. Other studies have assessed the validity of questionnaires and examined patterns of use over time, expecting a change in the individual's usage, concluding that a larger part of the variability is found between subjects rather than within subjects (Shimokura et al, 1998;Barbone et al, 2002).…”