A recent major study has found the rate of spontaneous abortion in nurses who handle chemotherapy drugs to be twice that of nurses who did not handle the drugs.

Past studies have reported similar results, but this study, a partnership between the National Institute for Occupations Safety and Health (NIOSH) and the Nurses’ Health Study 2, looked at pregnancy outcome and occupational exposures retrospectively from 8,461 participants in the Nurses’ Health Study 2. Participants reported 6,707 live births and 775 (10%) spontaneous abortions (less than 20 weeks).

The study looked at five potentially hazardous exposures: x-rays, chemotherapy drugs, sterilizing agents, anesthetic gases, and antiviral drugs. After adjusting for age, parity, shift work, and hours worked, regular antineoplastic drug exposure for more then one hour a day was associated with a twofold increased risk of spontaneous abortion, particularly before the 12th week, and a 3.5-fold increased risk among women with no previous pregnancies. Exposure to sterilizing agents was associated with a twofold increased risk of late spontaneous abortion (12–20 weeks). The rates varied by specialty area; the lowest rates were for medical/surgical and critical care (8.4% and 8.8%, respectively) and the highest for home health/community and oncology (13.1% each). The researchers found no increased risk of spontaneous abortion associated with anesthetic gases or antiviral drugs and a borderline association with exposure to x-rays.

Earlier studies showed increased risk of spontaneous abortion, but the studies suffered from small sample sizes and were conducted before safe handling measures were first recommended in 1985. An important limitation of the current study is that it did not collect information on measures to control exposure such as use of gloves, respirators, lead aprons, and ventilation or scavenging systems. Such data are currently being collected in the Nurses’ Health Study 3.

This study differed from previous studies in that the survey asked nurses how many hours they spent working with potentially toxic exposures, not about incidents where a nurse knew she had skin exposure. The researchers noted that nurses often don’t equate handling with exposure if they are using personal protective equipment (PPE). Previous research has shown that nurses are not always careful when handling chemotherapy drugs, sometimes foregoing gowns or gloves or using gloves that have not been tested for chemotherapy resistance. Future research is looking at what PPE is being used and collecting information on what the barriers are to following recommendations. The Nurses’ Health Study 3 survey asks about the types of exposures nurses have had, the types of PPE they wear, and how much time the nurses have spent working with the toxins.

The researchers noted that the study supports the need for nurses to assume alternative duties that don’t include handling toxic agents during pregnancy and times they are trying to conceive. They also recommended that women who are breastfeeding take extra precautions. They noted that the embryo is most vulnerable before a nurse knows she is pregnant. An unanswered question is whether men should also ask for alternative duties when trying to conceive because semen can be affected by chemotherapy drugs. The researchers recommended that all nurses take the time to use all PPE available and to insist that their employers provide the needed equipment.

The National Institute for Occupational Safety and Health recently updated its recommendations for safe handling of antineoplastic drugs.