Objectives To examine the association of occupational exposure to high-level disinfectants (HLDs) with risk of miscarriage among nurses.

Methods Our study included women who enrolled in the Nurses’ Health Study 3 (2010–2020) and had at least one pregnancy during follow-up. Occupational exposure to HLDs was self-reported at baseline. Every 6 months, a follow-up questionnaire was sent to participants asking for detailed information on pregnancies. We used a discrete-time Cox model to calculate the HRs and 95% CIs of miscarriage according to exposure to HLDs.

Results Our study included 2579 nurses with a median of 5.6 years of follow-up (range: 1–9 years), and we documented 768 (19%) cases of miscarriage among 3974 pregnancies. Compared with women with no HLD exposure, the HRs of miscarriage were 1.08 (95% CI: 0.87 to 1.34) for past users and 0.84 (95% CI: 0.68 to 1.04) for HLD users. Compared with women with no HLD exposure, duration, frequency, and type of HLD and use of exposure controls were not associated with risk of miscarriage. When restricting to pregnancies that occurred within 12 months of HLD use, occupational exposure to unspecified types of HLD was significantly associated with higher risk of miscarriage (HR=1.78; 95% CI: 1.08 to 2.93).

Conclusions We observed no associations between occupational use of HLDs and miscarriage, except when we restricted to pregnancies occurring within 12 months of assessed baseline exposure. Given the observational design and limited sample size, results should be interpreted cautiously.