Long work hours and exposure to anesthetics may raise pregnant veterinarians’ risk of premature delivery, a new study suggests.

To investigate possible occupational factor associated with prematurity, Dr. Adeleh Shirangi, of Imperial College London in the UK, and colleagues evaluated 399 female vets who had at least one baby.

They found a higher rate of preterm delivery among those who regularly used anesthesia without a “scavenging” system for clearing excess gas from the operating room.

Compared with other vets, women who had been exposed to unscavenged anesthesia gas for at least one hour per week were between two and three times more likely to delivery prematurely, Shirangi’s group reported in the journal Obstetrics & Gynecology.

Similarly, vets who worked more than 45 hours per week were nearly four times more likely to have a preterm birth than those with shorter work weeks.

The results add to an earlier study in which Shirangi’s team found that several exposures in veterinary practice - including unscavenged anesthetics, X-rays and pesticides - seemed to raise the risk of miscarriage.

The research suggests that female vets, and other women who work in the area, should take some precautionary steps, according to Shirangi.

Trimming back work hours and making sure the workplace is adequately ventilated are two measures, she told Reuters Health. The latter includes having anesthesia machines and scavenging systems regularly maintained to ensure they are working properly.

It’s also important, Shirangi noted, that all personnel working in the field be educated about the potential risks of various on-the-job exposures.

The link between unventilated anesthesia gas and preterm delivery is a new finding, Shirangi said, but it may also be relevant for women in other medical fields who are exposed to such chemicals - including surgeons, surgical nurses, anesthesiologists and dentists.

Long work hours, the researcher noted, have been previously linked to premature delivery in studies of women in other medical fields, such as nursing.

SOURCE: Obstetrics & Gynecology, May 2009.