Pregnancy is a life-changing event that comes with a slew of anxieties. If you work in a lab, those worries are likely to be compounded by concerns about chemicals and other potential hazards. Well, there is good news and bad news. The good news is that a number of studies have shown that lab workers have no or only slightly increased risk of pregnancy problems compared to the general population. The bad news is that those studies aren't conclusive, some chemicals may cause heightened risk, and--according to Allen Niemi, director of occupational safety and health services at Michigan Technological University in Houghton--very few U.S. academic institutions have policies to provide guidance. Most of the existing policies deal with exposure to ionizing radiation.

Adding to the challenge is the fact that women very often hide a pregnancy early on because they want to avoid unwelcome attention. Many women don't want to be treated differently or to deal with questions and reactions from co-workers. "I personally kept a pregnancy secret for about 7 months when I was working in the construction industry, where sight of a woman alone was enough to cause unwanted attention," says Linda Tapp, president of Crown Safety, an occupational safety, health, and ergonomics consulting firm in Cherry Hill, New Jersey.

Catcalls aren't often heard in science labs, but women in science have other legitimate reasons to wait as long as they can to report their pregnancy. They may, for example, be concerned about the impact a pregnancy might have on their working relationship with colleagues and supervisors and hence their long-term career prospects. But a fetus is most vulnerable to chemical or radiological hazards during the first trimester, and for that reason, Tapp says, women working with potential hazards should report a pregnancy as soon as they know.

Overall, Not Much Risk

Most broad population studies comparing lab workers with nonlab workers show little overall increase in the risk of pregnancy complications or birth defects, although one study showed a tendency toward low birth weights and shorter gestational lengths in cases where either parent worked in a chemical factory. Still, the studies may not be large enough to reveal some associations, says Barbara Grajewski, a senior epidemiologist with the National Institute for Occupational Safety and Health.

"The Achilles' heel of these studies is that there are so many things lab folks are exposed to, it's hard to nail down which exposure is a problem," says Grajewski. Nevertheless, there has been progress. "The common thread that runs through these studies is ... solvents, sometimes general, sometimes specific." Organic solvents have long been suspects, but recent reports have begun to pinpoint specific agents, including chloroform and benzene. "That's sort of exciting. People keep [blaming] solvents, but which solvents?" she adds.

Not all dangers are due to chemical agents. There is some evidence that prolonged standing and working the night shift can lead to reproductive problems, says Grajewski.

Radiation

Radiological exposure has been linked to miscarriages, low birth weight, and other problems. But here too there are some uncertainties. "I think the jury is still out on what low-dose radiation does in terms of reproductive health outcomes," says Grajewski. Regulations regarding radiation exposure are complicated by the fact that several agencies have guidelines, and they aren't identical. Some states also have agreements with federal agencies to substitute state policies for federal ones. So check with your radiation safety officer to find out the regulations that apply to you.

In any case, once a woman declares her pregnancy, any institution is legally required to ensure that the fetus is limited to a radiation exposure of 0.5 rem, according to Robert Zoon, a radiation safety officer at the National Institutes of Health (NIH). The woman must stop doing tasks that cause exposure once the exposure to the fetus approaches that limit. However, if a woman does not declare herself pregnant, the institution is under no obligation to limit exposure to the fetus, only to the worker, Zoon says. Dose is generally monitored using radiation badges or an electronic detection device.

Personal Guarantees

Aside from radiation, few U.S. organizations have policies regarding pregnant lab workers, which means women are on their own when it comes to worrying about exposure during pregnancy. Recent studies are reassuring in showing that, overall, lab workers have little increased risk compared to anyone else, but particular hazards could pose a much greater risk.

How do you determine that risk? First off, it's important to consider the most serious hazards, such as teratogens and biological agents capable of infecting the fetus. "You need to learn about those risks and how they can be safely managed before making the decision whether or not to work with them," says W. Emmett Barkley, director of the office of laboratory safety at the Howard Hughes Medical Institute in Chevy Chase, Maryland.

Niemi proposes a systematic approach to gathering information for women who are or want to become pregnant, as well as any woman of childbearing age who can't be certain she won't become pregnant. The first step is to list the hazards you could be exposed to through your own work or through a co-worker's work, including chemical, biological, and radioactive agents. Then get two or three sources of health information about each one. Material safety data sheets (MSDS) are a good place to start. Other resources include the National Institute for Occupational Safety and Health, the Occupational Safety and Health Administration, and the Merck Index. State agencies are also useful sources.

Next, Niemi says, take the list of problem reagents to your doctor and talk about it in the context of the potential means of exposure. A visit with a safety officer is also in order in considering how to minimize exposure. Many companies and organizations also have industrial hygienists or toxicologists on staff or on call, as well as specialists in occupational medicine, whose job it is to monitor and treat exposures.

Barkley emphasizes communication. "My general guidance is to speak openly with the senior scientist of the lab. We encourage discussion of risk, and this should be freely pursued. Labs have often made provisions where a person would [temporarily have someone else] carry out work with a particular agent or chemical. I would also encourage people to draw upon the expertise of an occupational medicine physician."

Most biomedical research organizations have a contract for occupational medical services, says James Schmitt, medical director for the occupational medical service at NIH, but they should be a last resort. Scientists "should work closely with a safety specialist. Primary prevention strategies are [handled by] the safety specialist, who engineers out the hazard or fixes things in a process or equipment. Occupational medicine is more secondary prevention--early detection, or if a woman becomes ill, determine if it's related to an exposure. The occupational medicine provider should be complementary to the safety specialist."

Always Use Protection

Niemi also emphasizes proper use and careful choice of protective equipment, including engineering controls such as fume hoods, disposable gloves, and respirators. Discard disposable gloves after one use, he says, because they really are designed for single use. "Personal protective equipment is where a lot of people make a mistake. They choose their own equipment and aren't sufficiently expert to use it properly. It gives you a false sense of security," Niemi says. Instead, consult with the safety officer to be sure of your choices and how to use them. Finding protective equipment that fits properly can be a challenge given the physical changes associated with pregnancy. "You [may] have to search a bit harder to find a proper fit. It's not impossible, it just means you can't buy just one brand," says Niemi.

In the end, laboratory pregnancies require more diligence than the average occupation. But your work shouldn't put a damper on the joy. "If good laboratory practices are used and those risks are managed well, there's no reason to think that a woman of childbearing age would be at an increased risk," says Barkley.

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Jim Kling is a freelance science and medical writer based in Bellingham, Washington.