Does Paternal Occupation and Lifestyle Affect Embryo Quality?

Abstract

Man is exposed to numerous exogenous as well as environmental chemicals through various routes. During the past 50 years, the rapid expansion of chemical industries in both the developed and developing countries has resulted in release of a plethora of xenobiotics into the environment. These alien molecules, including pesticides, herbicides, cosmetics, preservatives, cleaning materials, municipal and private wastes, pharmaceuticals and industrial by-products enter our bodies in a variety of forms. Exposure to chemical contaminants, which are estrogen mimics and endocrine disruptors, has been implicated as one of the possible factors contributing to the increasing male infertility. Environmental exposures of the father to the toxicants are linked to spontaneous abortion and / or congenital abnormalities in their off spring. Where the husbands are employed in an industry (chemical dyes, plastics, formaldehyde, etc.), their wives have about 90% greater risk of stillbirth. Exposure of the fathers to polyvinyl alcohol and benzene is associated with about 50% increase in preterm delivery. Men working in the agriculture industry face more than ten-fold increased risk of having infertility in comparison to those in other jobs. Lifestyle factors, like tobacco smoking, are deleterious to reproduction. Fathers who are “regular” drinkers have babies who weigh less than babies whose fathers are only “occasional” drinkers. Monosodium glutamate (MSG), a common flavor- enhancer added to foods, has been found to cause infertility problem in the offspring of MSG-treated male rats which had shorter body length and reduced testis weight. There are many evidences suggesting that parental chemical exposure to chemicals such as toluene, n-hexane, xylene, ethyl acetate, carbon disulfide, ethylene glycol ethers and their acetates, styrene, trichloroethylene, tetrachloroethylene, 1,1,1-tri-chloroethane, bisphenol, phthalates, etc., can potentially produce adverse effects on the progeny, particularly decline in embryo quality. Studies need to be focused on these occupational groups, by studying specific occupational exposure assessment, which should include not just the case history (with all its potential biases), but also results of environmental and biological surveillance (past and present data). Also, the causative agents need to be identified and appropriate preventive measures taken.