Association Between Consumption of Nitrate-Contaminated Water and Time to Pregnancy (TTP) Among Fertile Women

Abstract

ISEE-0580 Background and Objective: Nitrates are one of the pollutants in drinking water, produced in part by the excessive fertilization of fields and the inadequate management of the manure generated by livestock farmers. Evidence showing a consistent pattern of association between nitrates and adverse reproductive outcomes have been inconsistent and rare. The objective of this study was to analyze the association between nitrate levels in drinking water and Time to Pregnancy (TTP) among fertile women (in months). Methods: A cross sectional survey with retrospective collection design based on a questionnaire was conducted among female personnel who lived in small towns in the Comarca Lagunera, Mexico. Time to pregnancy (TTP) for first pregnancy was used to estimate the fecundability. After exclusions, 181 women remained for analysis. The fecundability Odds Ratios were calculated with a discrete time analogue of Cox’s proportional hazard model. Results: TTP mean, in months, in three different nitrate levels offers great differences (2.7, 3.2 and 4.2 months respectively). In the final multivariate model, the main predictor is the nitrate level adjusted by maternal age at first pregnancy and, marginally, maternal coffee consumption and paternal smoking habit. Fecundability OR (fOR) for level 2 and 3 were 0.78 (CI95% 0.38–1.55 ) and 0.53 (CI95% 0.26–1.05). Conclusion: The reduced fecundability in relation with different water levels of nitrates is slightly marginal, but with a clear tendency towards association and it is worth further study for precising specific damage. Future studies examining semen quality and characteristics of menstrual cycle are needed.