Exposure to either benzene or stress in the workplace increased a woman's chance of giving birth to a low weight baby. After eliminating other confounding factors such as passive smoking, exposure to noise and physical exertion at work, Dafang Chen and colleagues at Harvard’s School of Public Health (US) established the following:

• No exposure - average birthweight of baby 3445 grams
• Exposure to benzene only - average birthweight of baby 3430 grams
• Exposure to workplace stress only - average birthweight of baby 3426 grams
• Exposure to both benzene and workplace stress - average birthweight of baby 3262 grams

Earlier studies by other research teams showed that the toxins in benzene could reduce birthweight by suppressing cell growth in rapid growth areas like bone marrow, and by damaging cells generally. The researchers suggested that stress could reduce birthweight by increasing the release of adrenal and hypothalamic hormones, and speculated that the two processes could increase the negative effect of each other.

Ed.- Low birthweight can condemn a person to lifelong relatively poor health. The study’s findings reinforced fears that even very low exposures to benzene through its mother can damage a foetus. In this case, average maternal exposure was only a fifth of the safety limit recommended by the Occupational Safety & Health Association (OSHA) at that time. It also highlighted the need to consider the risks posed by combinations of possible factors rather than single factors in isolation.

IItalian research established that the partners of pesticide applicators working for Rome's Pest Control Centre ran a fourfold to sevenfold risk of spontaneous abortions compared to women whose partners worked in food retailing. Over the period of the study, the pesticide applicators' partners had 67 children and 26 spontaneous abortions compared to the food retailers' partners' 90 children and seven spontaneous abortions.

The researchers suggested that the wives were exposed to pesticide residues on their husbands' work clothes and that these pesticides then contaminated the womb. What appeared to be highly questionable work practices by the men's employer may have made the problem much worse. Not only would their clothes have been contaminated during the spraying, their job also involved preparing the pesticide mixes, which they carried out without wearing personal protective equipment.