This study aimed to examine factors associated with maternal wellbeing at four months post-partum in the Irish context. Socio-demographic, health behaviour and infant feeding data were collected in pregnancy, at birth and at 17 weeks post-partum. Maternal distress, body image and resilience were measured at 17 weeks post-partum. Binary logistic regression predicted maternal distress and statistical significance was taken at p < 0.05. One hundred and seventy-two women were followed-up in pregnancy, at birth and at 17 weeks post-partum. Three in five (61.6%, n106) initiated breastfeeding. At 17 weeks post-partum, 23.8% (n41) were exclusively or partially breastfeeding and over a third (36.0%, n62) of all mothers were at risk of distress. In multivariate analyses, independent predictors of distress included: low maternal resilience (p < 0.01, odds ratio (OR): 7.22 (95% confidence interval [CI]: 2.49–20.95)); unsatisfactory partner support (p = 0.02, OR: 3.89 (95% CI: 1.20–12.65)); older age (p = 0.02, OR: 1.11 (95% CI: 1.02–1.21)); and breastfeeding (p = 0.01, OR: 2.89 (95% CI: 1.29–6.47)). Routine assessment of emotional wellbeing and targeted interventions are needed to promote a more healthful transition to motherhood among women in Ireland.