ABSTRACT
Background Limited epidemiological evidence suggests a link between antibiotic use and the development of depression. This study seeks to investigate this association in-depth, using a cohort of pregnant individuals. The primary aim is to explore any association between antibiotic use during pregnancy, delivery, and within 12 months postpartum, and the development of antenatal and/or postpartum depression. Methods A national prospective, observational, longitudinal cohort study has been designed to examine the relationship between the use of antibiotics during pregnancy and the development of antenatal depression up to the third trimester (32-42 weeks), as well as the use of antibiotics during pregnancy and within 12 months postpartum and the development of depression during the postpartum period. The development of depression is considered as either a diagnosis by a medical doctor and/or a scoring 13 or higher on the Edinburgh Postnatal Depression Scale. Data will be collected using online surveys, during the third trimester, and at 6 weeks, 6 months, and 12 months postpartum. These surveys include a wide range of variables previously identified as being associated with antenatal and postpartum depression (such as level of social support, history of depression, and intimate partner abuse), as well as antibiotic and probiotic use. The impact of the COVID-19 pandemic on both participants’ pregnancy experience and their mental health will also be explored. Recruitment began in August 2021, using a combination of online paid and unpaid advertisements, as well as distribution of the study flyer in relevant clinics and public spaces. It is anticipated that data collection will be completed in early 2024. Discussion This study will provide a much-needed update on the prevalence of depression during pregnancy and postpartum, and its associated factors. It will also, for the first time, comprehensively explore the potential association between antibiotic use during pregnancy and up to 12 months postpartum and the development of depression. Additionally, it will provide a better understanding of the mental health impacts of the COVID-19 pandemic on pregnant individuals in Australia.