Medicine: Warning on Anaesthetics

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Doctors have long recognized that anaesthetics should be used only with extreme care. Some patients have allergic reactions from anaesthesia, and in rare cases the effects are fatal. There are now indications that anaesthesia may also affect the unborn. Writing in Anesthesiology, a team of researchers at the Stanford University School of Medicine report their suspicion that pregnant medical personnel whose work exposes them to anaesthetics may have miscarriages as a result.

The three researchers—Drs. Ellis Cohen and J. Weldon Bellville and Biostatistician Byron Brown—conducted parallel studies on two groups of women who serve in hospitals. The first study reviewed the miscarriage rates of 159 nurses. Among the 67 operating-room nurses queried, 29.7% of the pregnancies occurring over a five-year period ended in miscarriage; among the 92 nurses assigned elsewhere in the hospital, only 8.8% of pregnancies ended in spontaneous abortion. The second study involved 131 women physicians, 50 of them anaesthesiologists, the rest used as a control group. Only 10% of the pregnancies that occurred in the control group over a six-year period resulted in miscarriages. Among the anaesthesiologists, the rate was 37.8%.

The Stanford team believes that a large portion of the miscarriages among operating-room personnel may have been caused by inhalation of trace amounts of chemicals that were present in the O.R. atmosphere. The researchers urged further studies to determine whether there is a cause-and-effect relationship. But the authors are not waiting until those studies are completed before issuing a warning about the newly recognized hazard. They have installed better air-filtering machinery in operating rooms at Stanford and suggested that physicians treating pregnant women avoid anaesthesia whenever possible.