What should you do if a pregnant employee works in a high noise area? Consider these choices:

  • Do nothing.
  • Assure compliance with OSHA standards.
  • Transfer employee to a quiet work area.
  • Manage hazard through a workplace reproductive health program.

Only the last option is viable. "Do nothing" is a risk decision that may incur company and possibly personal liability if the unborn child is eventually identified with hearing problems. Compliance with OSHA standards does not ensure fetal protection. A transfer in this case may violate an employee's civil rights. And other hazards (such as ototoxic chemicals) to fetal hearing may be present in the quiet area.

Growing risks

This subject is worth your attention. Consider these developments:

1) Studies show that there may be nearly one million women in the workforce who may be pregnant at one time. Noise is pervasive in workplaces, and to a lesser degree, so are ototoxic chemicals and other hazards to fetal hearing.

2) The Bush administration continues to bring human embryos and fetuses under federal health protection, classifying them now as "unborn children" or "human subjects." Rapid advances in science, technology, and newborn screening practices will identify more workplace reproductive hazards.

3) Employees are seeing reduced coverage for health insurance. The financial and emotional costs for caring for a child with birth defects or developmental disabilities can be enormous. In absence of government standards for safe levels of exposure to workplace reproductive hazards, employees may feel they have little recourse but to seek legal action against employers who may have done them and their child wrong. More courts are recognizing the rights of children to sue for birth problems resulting from their parent's workplace exposures. These court actions bypass workers' compensation remedies.

Rise in newborn hearing tests

A growing number of states, 37 at last count, require newborn babies to have their hearing checked before they leave the birthing hospital. Hearing tests for babies are possible now because of rapid advances in technology and greater understanding of developmental biology.

Hearing tests are accomplished by attaching electrodes to a baby's forehead, shoulder, and back of the neck. Earphones placed over the baby's ears provide signals to the inner ear and brain-wave response to the signals are computer analyzed to determine if there are hearing problems. The test may be accomplished when the baby is just a couple hours old and can be conducted even while the baby sleeps.

Hearing loss is one of the most common problems found in newborns, affecting 12,000 children born in the U.S. each year. Early diagnosis of hearing loss allows for intervention and treatment to help avoid delays in speech, language, and intellectual development.

Genetic factors are believed to account for more than 50 percent of all cases of hearing loss in babies. Other causes for hearing loss include prenatal infections, illnesses, and other conditions or exposures occurring during fetal development.


The American Academy of Pediatrics policy statement "Noise: A Hazard for the Fetus and Newborn (RE9728)" concludes that exposure to excessive noise during pregnancy may result in high-frequency hearing loss in newborns. The American Conference of Governmental Industrial Hygienists (ACGIH) suggests that noise exposure in excess of an 8-hour TWA of 115 dBC or a peak exposure of 155 dBC to the abdomen of pregnant workers, beyond the fifth month of pregnancy, may cause hearing loss in the fetus.

Note: We are only discussing prevention of hearing loss. Noise exposure to pregnant employees may need to be reduced to prevent/reduce other harmful effects such as premature delivery and intrauterine growth retardation, which result in low birth weight babies. The military, for example, has established guidelines that pregnant women should avoid any exposure to ambient noise greater than 104 dBA.

Measuring noise exposure

Sound level meters and audio dosimeters must be set on the C scale, slow response, with a 3 dB doubling average to meet ACGIH's noise exposure recommendations for pregnant employees. The C scale provides a better measure of sound energy being transferred to the fetus's cochlea. OSHA measurements are made on the A scale, slow response, with a 5 dB doubling average. Do not rely upon OSHA noise measurements. An OSHA dBA reading generally will be lower than a dBC reading.

Microphone placement for pregnant employees must be at the employee's abdomen. Contact a noise equipment manufacturer or a competent industrial hygienist to ensure best practices to achieve accurate noise measurement results for pregnant employees.

Ototoxic chemicals

Workplace chemicals such as arsenic, carbon monoxide, hexane, lead, manganese, mercury, propylene glycol, styrene, tin, and toluene are capable of causing cochlear-like damage that may produce both temporary and permanent hearing loss in adults. Some ototoxic chemicals can pass through the placental barrier. To err on the side of safety, all ototoxic chemicals should be suspected of being capable of causing hearing loss to a fetus. Ototoxic chemicals may also produce harm before the fifth month of pregnancy.

The U.S. government has not established safe levels of chemical exposure for protection of pregnant workers, but other countries have. Finland, for example, has established an 8-hour TWA for carbon monoxide to pregnant workers at 14 parts per million. The U.S. OSHA limit for carbon monoxide is 50 ppm as an 8-hour TWA and the limit does not address fetal protection.

Regulations in Finland also prohibit pregnant employees from being exposed to organic solvents such as hexane and toluene at more than ten percent of the Finnish occupational hygienic value.

U.S. employers should conduct their own risk assessments to establish what they believe is an acceptable level of exposure to pregnant employees to ototoxic chemicals and other hazards that may contribute to hearing loss in newborn babies. The risk assessment should address that ototoxic chemicals include drugs such as aspirin that may be freely dispensed to employees at the workplace. The risk assessment should also include knowledge of the signs and symptoms of ototoxicity including unexplained tinnitus, fullness or pressure in the ears, poor balance, visual problems, or other problems such as headache and poor memory.


"Employees have a fundamental right to know about potential reproductive health risks encountered in the workplace," according to the American College of Occupational and Environmental Medicine's Reproductive and Developmental Hazard Management Guidelines. Training is the best way to inform employees about the workplace hazards that may contribute to hearing loss in newborns.

Research shows that most Americans now obtain medical information online and the quality of the information is often suspect. Employer-developed training helps counter poor or misleading online health and safety information. Employee training on this topic should be integrated into required OSHA training for noise (such as hearing conservation) and chemicals (such as hazard communication program).


OSHA standards on noise exposure focus on hearing conservation, meaning "to sustain hearing that is present, regardless of whether it is impaired or not." Hearing conservation will not work for fetal protection. Prevention must be stressed to avoid creating hearing loss. Prevention often requires voluntary efforts for hazard control and management based upon the best available scientific evidence.

Program approach

Workplace reproductive hazards are best managed by a program approach that includes measurable goals and objectives. Next month's column will describe the process flow for a workplace reproductive health program.