It has been reported that pregnant women used more cosmetics daily than non-pregnant women. Phenoxyacetic acid is the main metabolite of phenoxyethanol, the most frequent preservative in cosmetics used in Europe, previously associated with reproductive effects (longer time to conception, endocrine disruptors in newborns and poorer verbal comprehension in children). In France, specialised platforms (PREVention ENvIronment Reproduction (PREVENIR)) in university hospital maternity wards are dedicated to evaluating environmental and occupational exposures in patients with pregnancy-related pathologies and supporting targeted prevention efforts. These platforms are composed of occupational health physicians, obstetrician-gynaecologists, midwives, occupational health nurses, and occupational health and environmental engineers. To assess the efficacy of these platforms, we developed a randomised clinical trial, the protocol for which is presented in this paper. The primary objective of the PREVENIR-G Study is to compare the change in urinary phenoxyacetic acid concentrations from baseline to 3 months postintervention between an intervention group and a control group. To date, the intervention has been integrated into routine care in certain facilities; however, its efficacy remains unproven. It is therefore essential to assess the relevance of this intervention, considering both its potential benefits and any adverse effects, such as increased stress or anxiety.

This study is an unblinded, randomised clinical superiority trial with two parallel groups (intervention vs no intervention) in four university maternity hospitals in France. We will include 300 pregnant women (aged 18 years or older) who are under 24 weeks of gestation (150 per group) referred to the participating PREVENIR platforms for management. The intervention will consist of clinical prevention management through the PREVENIR platforms, involving a consultation with an environmental health expert for an assessment of environmental and occupational exposures. During the consultation, targeted prevention messages will be provided based on identified exposures. The no intervention comparator will be a waiting-list control group. At the inclusion visit, patients will receive urine collection vials for samples to be collected at baseline and again at 3 months. Urine samples will be collected twice in a single day, on three separate days, during the collection week at home. In the week following the urine collection period, only participants in the intervention group will engage with the PREVENIR platforms. The primary outcome will be the difference in the urinary phenoxyacetic acid concentration between baseline and 3 months postintervention, compared between the intervention and control groups.

The study has been approved by the hospital ethics committee (CCP Ouest 2, no. 2023-A00941-44). All participants will provide written informed consent. Results will be shared through presentations and publications.

NCT06642818