Chlorination By-Products in Drinking Water and Menstrual Cycle Function

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Chlorination By-Products in Drinking Water and Menstrual Cycle Function

Gayle C. Windham,1 Kirsten Waller,2,* Meredith ,2

Fenster,1 ine Mendola,3 and Shanna Swan4

Environ Health Perspect 111:935-941 (2003).

Abstract: We analyzed data from a prospective study of menstrual cycle

function and early pregnancy loss to explore further the effects of

trihalomethanes (THM) on reproductive end points. Premenopausal women (n

= 403) collected urine samples daily during an average of 5.6 cycles for

measurement of steroid metabolites that were used to define menstrual

parameters such as cycle and phase length. Women were asked about

consumption of various types of water as well as other habits and

demographics. A THM level was estimated for each cycle based on

residence and quarterly measurements made by water utilities during a

90-day period beginning 60 days before the cycle start date. We found a

monotonic decrease in mean cycle length with increasing total THM (TTHM)

level; at > 60 µg/L, the adjusted decrement was 1.1 days [95% confidence

interval (CI), -1.8 to -0.40], compared with Less than or = to 40 µg/L.

This finding was also reflected as a reduced follicular phase length

(difference -0.94 day; 95% CI, -1.6 to -0.24). A decrement in cycle and

follicular phase length of 0.18 days (95% CI, -0.29 to -0.07) per 10

µg/L unit increase in TTHM concentration was found. There was little

association with luteal phase length, menses length, or cycle

variability. Examining the individual THMs by quartile, we found the

greatest association with chlorodibromomethane or the sum of the

brominated compounds. Incorporating tap water consumption showed a

similar pattern of reduced cycle length with increasing TTHM exposure.

These findings suggest that THM exposure may affect ovarian function and

should be confirmed in other studies.

Full text:

http://ehp.niehs.nih.gov/members/2003/5922/5922.html

http://ehp.niehs.nih.gov/members/2003/5922/5922.pdf

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1 California Department of Health Services, Division of Environmental

and Occupational Disease Control, Oakland, California, USA;

2 Sequoia Foundation, La Jolla, California, USA;

3 National Health and Environmental Effects Research Laboratory, U.S.

Environmental Protection Agency, Research Triangle Park, North Carolina,

USA;

4 Department of Family and Community Medicine, University of Missouri,

Columbia, Missouri, USA