Do you have any information regarding flight attendants and infertility? It took me seven years to have my one and only child. I am 35 years old.

S.Q.

There are no published studies that address the risk of infertility in flight attendants. But there may be factors involved in frequent flying that are of concern to women during their reproductive years. Flying in a commercial airliner is associated with a minimal increase in exposure to cosmic radiation. The risk to the infrequent traveller is minimal, but frequent business travellers, airline pilots and flight attendants may have a small but significant increased risk due to this exposure. Studies in the early '90s showed that flight attendants may have a 90 percent increase in risk of miscarriage compared with other women. However, compared with other working women, the increased risk fell to approximately 30 percent.

How have airlines approached this concern? They have not. More than half do not allow flight attendants to work beyond the third trimester. Still, policies that limit flying in the third trimester will not reduce the risk of miscarriage.

Is the increased risk of miscarriage due to cosmic radiation, hypoxemia (low oxygen associated with low cabin pressures), stress or working shifts at various times of the day? We don't really know. But any of these factors may contribute to fertility problems. More research is necessary before clear guidelines for airline attendants can be established.