BACKGROUND: Continuous support during labor has many benefits, including lower use of obstetrical interventions. However, implementation remains limited. Insights into birth outcomes as well as peripartum costs are essential to assess whether continuous care by a maternity care assistant is a potentially (cost) effective program to provide for all women. OBJECTIVE: Continuous care during labor, provided by maternity care assistants, will reduce the use of epidural analgesia and peripartum costs due to a reduction in interventions. STUDY DESIGN: A randomized controlled trial, comparing continuous support during labor (intervention group) to care-as-usual (control group) with pre-specified intention-to-treat and per-protocol analyses. The primary outcome was epidural analgesia use. Secondary outcomes were use of other analgesia, referrals from midwife- to obstetrician-led care, modes of birth, hospital stay, sense of control (evaluated with the Labor Agentry Scale), maternal and neonatal adverse outcomes and peripartum costs. Data were collected using questionnaires. Anticipating incomplete adherence to providing continuous care, both intention-to-treat and per-protocol analyses were planned. Peripartum costs were estimated using a healthcare perspective. Mean costs per woman and cost differences between the intervention and control group were calculated. RESULTS: The population consisted of 1076 women with 54 exclusions and 30 discontinuations, leaving 992 women to be analyzed (515 continuous care and 477 care-as-usual). Intention-to-treat analyses showed statistically non-significant differences between the intervention and control group for epidural use (RR 0.88, 95%-CI 0.74 to 1.04, p=0.14) and peripartum costs (mean difference € 185.83, 95%-CI -€ 204.22 to € 624.54). Per-protocol analyses showed statistically significant decreases in epidural analgesia (RR 0.64, 95%-CI 0.48 to 0.84, p=0.001), other analgesia (RR 0.59, 95%-CI 0.37 to 0.94, p=0.02), cesarean sections (RR 0.53, 95%-CI 0.29 to 0.95, p=0.03) and ...