Factors Related to Pregnancy and Childbirth and Their Relationship with Exclusive Breastfeeding—A Cross-Sectional Study

Background/Objectives: The World Health Organisation (WHO) recommends exclusive breastfeeding for the first six months of life, but exclusive breastfeeding (EBF) rates remain low in many countries, including Poland. Factors related to pregnancy, childbirth and the organisation of care can significantly affect the maintenance of lactation. There is a lack of representative data on these relationships in Poland, which makes it difficult to plan effective support measures. The aim of this study is to analyse the relationship between pregnancy and perinatal factors and exclusive breastfeeding in infants aged 6 to 12 months. Methods: This cross-sectional online survey was conducted between April and October 2025. A total of 557 women aged ≥18 years with infants aged 6–12 months participated in the research. Data were collected using a structured questionnaire covering sociodemographic characteristics, the course of pregnancy and childbirth, postpartum complications, early breastfeeding experiences and maternal birth satisfaction assessed using the Polish version of the Birth Satisfaction Scale—Revised (BSS-R). Multivariable logistic regression analysis was used to identify factors associated with exclusive breastfeeding up to six months. Results: Exclusive breastfeeding was significantly associated with vaginal delivery, the absence of postpartum complications and a lack of early breastfeeding problems in the first days postpartum, with initial lactation difficulties emerging as its strongest predictor. Most specific pregnancy-related conditions, maternal birth satisfaction and selected recommended hospital practices, including early skin-to-skin contact, were not independently associated with exclusive breastfeeding in the model. Conclusions: Exclusive breastfeeding up to six months is primarily determined by factors operating in the immediate perinatal and early postpartum period, particularly postpartum clinical stability and successful early lactation. Targeted support during this critical window may be key to improving exclusive breastfeeding outcomes.