The results of this study showed that IPT training is effective on maternal stress and adoption. Parents of premature infants are more exposed to stress associated with physical appearance, infant’s condition, and parenting problems (
22). Increased parental stress can lead to behavioral problems in mothers. Interpersonal psychotherapeutic approach, with correction of the relationship, shows positive and negative aspects to the person to reduce stress (
23). The IPT helps mothers identify their problems and by presenting a therapeutic contract, leads to changing stressful behaviors of the person and improves their mental health (
24). Another study showed the effect of IPT on decrease of depression, anxiety, and cortisol level during pregnancy (
25).
The results of this study showed that IPT increased adoption score in the intervention group. Motherhood is a woman’s greatest change, and women endure most challenges in this period in order to obtain this transition (
16).
Mothers, who have premature infants face many difficulties in the process of adaptation to a maternal role (
26). One study showed that women, who give birth to healthy infants have a higher score of adaptation to their maternal role and child health is effective on adaptation to maternal roles.
A study showed that the neonatal behavior can cause maternal stress, which causes loss of maternal competence (
27). The interaction between the mother and neonate is usually the most important factor in growth and development of premature infants (
28). Mothers of premature infants are at risk of developing attachment problems and reduced responsiveness to the neonate. Preterm infants look less to their care-giver and respond less to sounds than other infants (
29). Therefore, weakness in parent-child behaviors and relationships can lead to decreased interpersonal relationships in mothers, while IPT can lead to the formation of role transition and improves self-efficacy (personal judgment of one’s own ability to cope in a specific situation) (
30) by increasing the mother-child’s attachment and adoption of the mother’s role (
23). One study showed the effect of IPT on parental competence and social support of primiparous women and identified better interpersonal communication as a factor for emotional support of mothers and empowered them in taking care of the infant and home responsibilities (
16). Previous studies reported the effect of IPT in the short term (
31). However, other studies have also shown the effect of psychotherapy on reducing postpartum depression and improving mental health of mothers, lasting for up to three months after childbirth (
16). In this study, maternal role adaptation was measured immediately and two weeks after the intervention, and the mean score was higher two weeks after compared with immediately after the intervention, which may have been due to the support of others, time transition, and access to other sources of information. In the control group, 90.6% and in the intervention group, 84.1% of the mothers had the support of others. A study showed that maternal competence increases in the last trimester of pregnancy up to four months postpartum (
32). Mothers experience behavioral and cognitive changes and IPT helps reduce stress and accepting mother’s role, by positive thinking and encouragement for a better motherhood (
14).
One of the limitations of this research was the post-intervention follow-up period; it is suggested to design a study with a longer follow-up to explore the continued effect of the IPT program. It is also suggested for studies to investigate the influence of IPT with the presence of fathers of infants admitted to the NICU. Controlling the access of participants to other information sources, such as the Internet and other media was another limitation of this study.