Background Tertiary obstetric centers are responsible for the care of all their newborns and for supporting mothers during breastfeeding. The aim of this work is to analyze the development and prevalence of breastfeeding initiation in a tertiary obstetric center. Subsequently, factors influencing the initiation of breastfeeding will be investigated. Methods This is a retrospective study collecting data of all births of a non-selected cohort from 2017 to 2022 of singleton pregnancies at the Medical School of Hannover, Germany. Retrospective data of 16,092 women were used. We examined type of infant nutrition in our maternity unit in mothers by self-report, which was a routine survey conducted by a breastfeeding and lactation consultant within the framework of the perinatal quality assurance initiative. Secondly, factors impacting breastfeeding initiation were investigated (maternal BMI, gestational age, parity, special risk factors and birth mode) using a second cohort of 4,603 mother-child-pairs of live born, singleton full-term newborns. Results Over the observed period, the rate of ever breastfeeding women was 93% in 2017 and 83% in 2022 indicating decreased adherence to breastfeeding. The rate of exclusively breastfeeding at the breast decreased by 21% over observed period (from 78 to 57%). While the group of feeding infant formula only and breastfeeding cessation before discharge remained stable, the rate of supplementary feeding, and breastfeeding and feeding infant formula, increased significantly. The rate of exclusive breastfeeding at the breast was lower in the groups of obese compared to normal-weight women (59.1% vs. 78.2%), women undergoing a cesarean section in comparison to vaginal birth (62.3% vs. 78.1%) and deliveries at 38 weeks of gestation compared to 40 weeks of gestation (62.7% vs. 77.3%). The infants of women with diabetes mellitus (74.2% vs. 62%) or gestational diabetes (74% vs. 65%) were significantly more likely to require infant formula than those without risk factors. Conclusions Those women with the potentially highest benefit of breastfeeding to not exert their potential for risk reduction. Adequate awareness among healthcare professionals is imperative to capitalize on the brief but substantial opportunity to influence breastfeeding behavior in a tertiary obstetric center.