Exposure in Health Care: Pregnancy Outcome and Fertility

1. Exposure in Health Care: Pregnancy Outcome and Fertility Marja-Liisa Lindbohm Finnish Institute of Occupational Health

2. Health care work: exposures • Chemicals: anesthetic gases, antineoplastic agents, sterilizing agents, solvents, mercury • Radiation • Biological agents • Physical strain • Irregular working hours

3. Reproductive effects of anesthetic gases • in several human studies exposure related to • spontaneous abortions • congenital malformations • reduced fertility in women • in some studies exposure related to • reduced birth weight • increased risk of small for gestational age • spontaneous abortion among the wives of exposed men and malformations in their offspring

4. Anesthetic gases and spontaneous abortions: a meta-analysis (Boivin 1997) • 19 studies published in 1971 – 95 • Relative risk 1.48 (95% CI 1.4 – 1.58) • Analysis limited to 6 most valid studies: relative risk 1.9 (95% CI 1.72 – 2.09) • Conclusion: the available data suggest that a real risk may be present

5. A study of dental assistants exposed to nitrous oxide (Rowland et al 1992, 1995) • 7000 dental assistants • Telephone interview, 69% responded • Reduced fertility in women exposed to 5 hours per week to unscavenged nitrous oxide • Increased risk of spontaneous abortion among women exposed  3 hours per week to unscavenged nitrous oxide

6. A study of midwives exposed to nitrous oxide (Ahlborg et al 1996, Bodin et al 1999) • 3985 midwives • A mailed questionnaire, 84% responded • Reduced fertility in women assisting >30 deliveries/month (FR 0.63, 95%CI 0.43 – 0.94) • No increased risk of spontaneous abortion • Reduced birth weight (-77 gm, 95%CI –129, -24) and increased risk of infants being small for gestational age (OR 1.8, 95%CI 1.1 – 2.8)

7. Enflurane, etomidate, fentanyl, halothane, isoflurane, propofol, sevoflurane, thiopental • Data limited and no human studies on the effects of occupational exposure to these agents • Halothane: increased frequency of developmental delay in some experimental studies, but not all, and behavioral abnormalities among the offspring • Enflurane and isoflurane evaluated: animal data show that no classification for toxic to reproduction is indicated • Thiopental: no increased risk of malformations in women treated during pregnancy

8. Suggested new guidelines for concentrations of anesthetic gases during pregnancy in Finland • Nitrous oxide 10 ppm (TLV for all:100 ppm) • Halothane 0,1 ppm (TLV for all: 1 ppm) • Desflurane 10 ppm • Enflurane 10 ppm • Isoflurane 10 ppm • Sevoflurane 10 ppm

9. Anesthetic gases: exposure assessment Exposure may be high in: • operating rooms with poor ventilation or no efficient scavenging equipment • delivery rooms • administration of anesthesia to small children in arms • veterinary operating rooms • dental offices

10. Antineoplastic agents and reproductive health • increased risk of malformations and reduced probability of live births in treated patients • teratogenic in animal experiments • occupational exposure related to: • menstrual dysfunction • infertility • spontaneous abortions • congenital malformations

11. Maternal occupational exposure to antineoplastic agents and spontaneous abortion

12. Antineoplastic agents: hazard assessment • Exposure may be high in: • dilution and preparation of the solutions • cleaning of the preparation room • injection/infusion of the drugs • handling of the excreta of patients • Guideline: a pregnant worker should not do these jobs

13. Ethylene oxide and adverse pregnancy outcome • Used as a sterilant in hospitals, and in medical and dental offices • Mutagenic, teratogenic and carcinogenic agent • Increased risk of spontaneous abortion in exposed hospital sterilising staff and dental assistants • Increased risk of preterm and postterm birth • Exposure should be avoided

14. Maternal exposure to solvents in laboratories or health care sector and spontaneous abortion

15. Ionizing radiation and pregnancy outcome • High doses known to be harmful to reproductive health • Findings on the reproductive effects of occupational exposure are contradictory • increased risk of spontaneous abortion reported among veterinarians and radiology technicians • no excess of malformations or cancer in children of radiographers, but a slight increase of chromosomal anomalies other than Down

16. Ionizing radiation: exposure assessment • The protection of the fetus must be comparable with that provided to the members of the public • The equivalent dose of radiation should not exceed 1 mSv during the remainder of the pregnancy • Recommendation: a pregnant worker should not hold patients during x-ray or give regularly isotope treatment

17. Non-ionizing radiation and adverse pregnancy outcome • Physiotherapists may be exposed to short-waves, microwaves and ultrasound • MRI technologists may be exposed to strong static magnetic fields • Evidence on their adverse reproductive effects is inconclusive • Increased risk of spontaneous abortion and low birth weight related to use of short-wave equipment • EU guideline: exposure to short waves should be minimised

18. References on exposures in health care and reproductive health • Figà-Talamanca I. Reproductive problems among women health care workers: epidemiologic evidence and preventive strategies. Epidemiologic Reviews 2000;22:249-260. • Boivin J-F. Risk of spontaneous abortion in women occupationally exposed to anesthetic gases: a meta-analysis. Occup Environ Med 1997;54:541-548. • Ahlborg G, Hemminki K. Reproductive effects of chemical exposures in health professions. J Occup Environ Med 1995;37:957- 961.