Late preterm and full-term infants comprise the majority of births in our hospital which serves a multicultural lower socioeconomic community. Patients give birth vaginally (normal birth, NB) or by cesarean birth (CB), and the majority of neonates are exclusively breastmilk fed until discharge. In this study we examined what factors within these two birth modes and feeding regimes of exclusive breast milk were associated with early postnatal readmission. Ideally, findings will aid initiatives to decrease readmission rates. A retrospective cohort study was performed on maternal-infant pairs. All neonates from 2016 to 2018, exclusively breastmilk fed at discharge, born by NB (n = 4245) or CB (n = 1691), were grouped as non-Readmitted (Reference) or Readmitted within 30 days of discharge. Readmission reason was determined, and potential associations were identified using univariate analysis and multivariable logistic regression. Rates of readmission were similar for both NB and CB infants (6.8% vs. 7.3%). In order, NB concerns were jaundice, infection, and feeding-this was reversed for the CB Group. NB readmission bilirubin levels were higher (293 ± 75 vs. 236 ± 112, μmol/L, NB:CB, p < 0.001). Factors associated with readmission for both groups were similar to previously published studies. Edinburgh Postnatal Depression Score (EPDS) was higher for Readmitted infant mothers. Importantly, for non-jaundice readmission EDPS categories indicated that both CB and NB mothers were more likely to have depression. Early readmission of exclusively breastmilk-fed infants born by means of NB or CB is multifactorial. Early pregnancy mental health issues are associated with readmission, highlighting the potential effects of perinatal depression on neonatal health.