Objectives We examined the mental health of mothers after unaccompanied birth (unaccompanied group, UG) due to COVID-19-related visiting bans and compared the data with a control group with accompanied birth (AG). Additionally, a distinction was made between caesarean section (CS) and vaginal birth (VB), as existing research indicates a higher risk for mental distress after CS. Methods The cross-sectional study included 27 mothers in the UG and 27 matched controls (AG). Anxiety, depression, postpartum traumatic stress symptoms (PTSS), and psychological well-being were assessed. Additionally, emotions and attitudes related to the restrictions were measured by self-developed items. Results Psychological distress was high especially in the UG (anxiety: 23%, PTSS: 34.6%, low well-being: 42.3%, depression: 11.5%). Mothers in the AG had lower psychological distress than those in the UG, but still had enhanced rates of PTSS (11.1%) and diminished well-being (22.2%). In both groups, women with CS reported higher anxiety and trauma scores and lower well-being than women with VB. Unaccompanied mothers with CS perceived visitation restrictions as less appropriate and felt more helpless, angry, worried, and frustrated about the partner’s absence than women with VB. Conclusions The partner’s absence during, but also after childbirth has a major impact on psychological outcomes. Particularly, higher rates of anxiety and PTSS can lead to negative consequences for mothers and their children. Therefore, it is strongly recommended to relax visitation bans and avoid unaccompanied births. Psychological treatment in obstetric units is more urgently needed than ever, especially for women with a caesarean section.