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

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

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).

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.

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