Occupational exposure to ethylene oxide during pregnancy and association with adverse reproductive outcomes

Abstract

Objective: To investigate the association between exposure to ethylene oxide during pregnancy and adverse reproductive outcomes.

Methods: Singleton pregnancies were analysed that: (1) had occurred in women working at the time of the study (2004) in hospital sterilising units using ethylene oxide in Gauteng province, South Africa; (2) was the last recognised pregnancy of these women after the 1 January 1992; and (3) this last recorded pregnancy had occurred while the mother was employed. An adverse reproductive outcome was defined as the occurrence of a spontaneous abortion, still birth or pregnancy loss (combined abortion + still birth). Information on the evolution and outcome of the pregnancy was gathered from the mother using a questionnaire. Information on exposure to ethylene oxide during pregnancy was obtained from three sources, namely walk-through surveys, questionnaire-collected data and measurements of the levels of ethylene oxide in sterilising units at the time of the study (personal and static sampling).

Results: The study enrolled 69% of the hospitals in Gauteng using ethylene oxide to sterilise medical equipment. The participation rate for women employed in these sterilising units was 97%, and the study population consisted of 98 singleton pregnancies. Measurements of ethylene oxide showed that operators of sterilisers were still potentially over-exposed. There was a significantly increased risk of spontaneous abortion (POR = 20.8, 95% CI = 2.1-199) and pregnancy loss (POR = 8.6, 95% CI = 1.8-43.7) for pregnancies highly exposed to ethylene oxide compared to low exposed pregnancies. No associations were found between exposure to ethylene oxide and stillbirth.

Conclusions: An increased risk of spontaneous abortion and pregnancy loss was found to be associated with exposure to ethylene oxide during pregnancy.