Pre-pregnancy predictors linked to miscarriage among Aboriginal and Torres Strait Islander women in North Queensland

Objective: Identify preventable pre-pregnancy risk factors that may affect the prevalence of miscarriage among a cohort of Australian Indigenous women. Methods: Data from 1,009 Indigenous women of childbearing age who participated in a 1999-2000 health screening program in far-north Queensland were linked to Queensland hospitalisation data. Women who attended hospital after their health check (censor date: March 2008) for a pregnancy-related condition were identified. Characteristics associated with becoming pregnant and subsequent miscarriage were analysed using generalised linear models. Results: After adjusting for age and ethnicity, women who became pregnant were more likely to be smokers and to have low red cell folate at baseline. The risk of miscarriage increased with age. Women who reported risky drinking or had elevated gamma-glutamyl transferase were also at higher risk. After further adjustment for risky drinking, the presence of chlamydia or gonorrhoea before pregnancy was associated with miscarriage. The presence of both infections at baseline compared with women who had no infection, again after further adjustment for risky drinking, was strongly associated with miscarriage; these women had more than a four-fold increase in risk (PR: 4.57 [ 2.21-9.46]). Elevated body mass index, high blood pressure and smoking were not statistically significantly associated with risk of miscarriage. Conclusions and implications: A high prevalence of pre-pregnancy sexually transmitted infections and high rates of risky drinking are associated with miscarriage among young Indigenous women in rural and remote communities in north Queensland.