Face-to-face mother-infant interaction: differences between depressed and non-depressed mothers and according to the infant's sex

Universidade do Minho Escola de Psicologia Leonor Macho da Costa Face-to-face mother-infant interaction: Differences between depressed and nondepressed mothers and according to the infant's sex january, 2023 Face-to-face mother-infant interaction: Differences between depressed and non-depressed mothers and according to the infant's sex Leonor Macho da Costa Uminho | 2023 Universidade do Minho Escola de Psicologia Leonor Macho da Costa Face-to-face mother-infant interaction: Differences between depressed and nondepressed mothers and according to the infant's sex Masters Dissertation Integrated Master in Psychology Work supervised by Professor Doctor Bárbara Figueiredo and Professor Doctor Raquel Costa January, 2023 DIREITOS DE AUTOR E CONDIÇÕES DE UTILIZAÇÃO DO TRABALHO POR TERCEIROS Este é um trabalho académico que pode ser utilizado por terceiros desde que respeitadas as regras e boas práticas internacionalmente aceites, no que concerne aos direitos de autor e direitos conexos. Assim, o presente trabalho pode ser utilizado nos termos previstos na licença abaixo indicada. Caso o utilizador necessite de permissão para poder fazer um uso do trabalho em condições não previstas no licenciamento indicado, deverá contactar o autor, através do RepositóriUM da Universidade do Minho. Licença concedida aos utilizadores deste trabalho Atribuição-NãoComercial-CompartilhaIgual CC BY-NC-SA https://creativecommons.org/licenses/by-nc-sa/4.0/ iii Acknowledgments Primeiramente quero agradecer à minha Orientadora, Professora Doutora Bárbara Figueiredo, pelo seu apoio, paciência e dedicação. Sem dúvida alguma, uma fonte de inspiração, que além de me motivar também me ajudou a crescer e me ensinou a lidar melhor com as adversidades e dificuldades que fui encontrando ao longo desta jornada. De seguida quero agradecer à minha coorientadora, Professora Doutora Raquel Costa, por toda a sua disponibilidade, apoio e interesse. Agradeço, ainda, a todo o Grupo de Investigação, em especial à minha querida Bárbara, parceira desta viagem, que partilhou e esteve a meu lado desde os momentos mais complicados aos mais felizes. Quero agradecer aos meus grandes amigos, Beatriz, Inês, João e Soraia pela ajuda, apoio e confiança que me deram ao longo deste ano. É nestas alturas mais stressantes e exigentes que se revelam os verdadeiros amigos, e com isto posso afirmar que sou eternamente grata por os ter na minha vida. Quero ainda agradecer à minha psicóloga por todo o apoio e reflexão que me fez ter, sem dúvida uma pessoa indispensável no meu crescimento ao longo desta jornada. Por fim, quero agradecer à minha família pela preocupação, interesse e apoio. Por sempre me incentivaram a seguir os meus sonhos e a nunca desistir. Agradecer aos meus pais por todo o esforço que fizeram para me puder conceder esta oportunidade de formação, e em especial à minha tia Vivi, por toda a ajuda e incentivo, sem dúvida uma excelente pessoa com um enorme coração. Assim, termino com um grande obrigada a todos aqueles que de uma forma ou outra fizeram parte desta jornada. iv STATEMENT OF INTEGRITY I hereby declare having conducted this academic work with integrity. I confirm that I have not used plagiarism or any form of undue use of information or falsification of results along the process leading to its elaboration. I further declare that I have fully acknowledged the Code of Ethical Conduct of the University of Minho. University of Minho, 30th January 2023 Signature: _______________________________ v Interação face a face mãe-bebé: Diferenças entre mães deprimidas e não deprimidas e de acordo com o sexo do bebé Resumo A interação face a face é um contexto chave para entender a qualidade da interação mãe-bebé, sendo que pode ser influenciada por fatores externos que estão bastante presentes na atualidade. Desta forma, este estudo tem como objetivo (1) analisar diferenças na interação face-a-face mãe-bebé entre mães deprimidas e mães não deprimidas no pós-parto, e (2) analisar diferenças na interação face-a-face mãe-bebé entre o sexo do bebé (raparigas vs rapazes). A amostra foi composta por 63 mulheres recrutadas no 3º trimestre da gestação, maioritariamente portuguesas (92%). Os instrumentos utilizados neste estudo foram: Questionário Sociodemográfico, Escala de Depressão Pós-Natal de Edimburgo e Escala de Avaliação da Interação. Os resultados revelaram que (1) a depressão influencia alguns comportamentos maternos, como a reduzida atividade física significativa e o aumento da presença de expressões faciais de tensão e raiva. Bem como revelaram que (2) o sexo do bebé influencia o modo como este interage com a mãe, sendo que os rapazes têm comportamentos mais direcionados para a mãe do que as raparigas. Em suma, é importante implementar programas educativos para grávidas e mães recentes, de forma que estas consigam responder adequadamente a possíveis comportamentos que possam existir durante a interação face a face. Palavras-chave: Depressão pós-natal; face a face; interação mãe-bebé; sexo do bebé vi Face-to-face mother-infant interaction: Differences between depressed and non-depressed mothers and according to the infant's sex Face-to-face interaction is a key context for understanding the quality of mother-infant interaction and can be influenced by external factors that are strongly present nowadays. Thus, this study aims to analyze (1) differences in face-to-face mother-infant interaction between depressed mothers and non-depressed mothers in the postpartum period, and (2) to analyze differences in face-to-face mother-infant interaction between the sex of the infant (females vs males). The sample was composed of 63 women recruited in their third trimester of pregnancy, mostly Portuguese (92%). The instruments used in this study were: Sociodemographic Questionnaire, Edinburgh Postnatal Depression Scale, and Interaction Rating Scale. The results revealed that (1) depression influences certain maternal behaviors, such as reduced significant physical activity and increased presence of facial expressions of tension and anger. They also revealed that (2) the sex of the infant influences the way they interact with their mother, with males having more motheroriented behaviors than females. In summary, it is important to implement educational programs for pregnant women and recent mothers so that they can respond appropriately to possible behaviors that may exist during face-to-face interaction. Keyword: Face-to-face; mother-infant interaction; postnatal depression; sex of the infant vii Contents Introduction……………………………………………………………………………………………………………………………..9 Method…………………………………………………………………………………………………………………………………11 Participants………………………………………..………………………………………………………………………11 Procedure…………………………………………………………………………………………………………………..13 Measures……………………………………………………………………………………………………………….....13 Sociodemographic Questionnaire…………………………………………………………………………………….13 Edinburgh Postnatal Depression Scale (EPDS)…………………………………………………………………..14 Interaction Rating Scales (IRS)……………………………………………………………………………….……….14 Statistical analysis………………………………………………………………………………………………………..15 Results………………..…………………………………………………….………………………………………………………....15 Discussion…………………………………………………………………………………………………………………………….21 Limitations and strengths…………………………………………………………………………………………………………23 Implications for clinical practice and research……………………………………………………………………………...23 Conclusion…………………………………………………………………………………………………………………………….24 References…………………………………………………………………………………………………………………………….25 Appendix ……………………………………………………………………………………………….....……………………….…30 FACE-TO-FACE MOTHER-INFANT INTERACTION: DIFFERENCES BETWEEN DEPRESSED AND NON-DEPRESSED MOTHERS AND ACCORDING TO THE INFANT'S SEX 14 Edinburgh Postnatal Depression Scale (EPDS): The Edinburgh Postnatal Depression Scale (EPDS) (Cox et al., 1987) was used to assess depression symptoms. It is a self-report questionnaire and a simple means to screen for postnatal depression in healthcare settings. This scale reveals the intensity of depressive symptoms relative to the previous seven days and has been used in several studies during pregnancy and the postpartum period (Figueiredo et al., 2013). In this study, we used the Portuguese version (Augusto et al., 1996), which was composed of 10 items, and scored on a 4-point Likert scale (0-3). It has good internal consistency (Cronbach's alpha= 0.85) and test-retest reliability (Spearman Correlation= 0.75) (Figueiredo & Costa, 2009). According to Tendais et al. (2014), the optimal cut-off score is 7 for postpartum, and for that reason, the same cut-off point for the detection of depressed mothers in this study was used. Interaction Rating Scales (IRS): The Face-to-Face Interaction Rating Scale (IRSff) (Field, 1980) was used to evaluate the face-to-face mother-infant interaction at 3 months post-partum. This scale was initially developed for Field (1980) and validated for the Portuguese population by Figueiredo and Dias (2013). The IRSff consists of 10 items assessing the mother's interactive behavior and 10 items assessing the infant's interactive behavior, in a faceto-face context. Each item is rated on a scale from 1 to 3 points, where the maximum value of the rating of each subscale and the total scale is 3. Higher values indicate better quality in the behavior of both mother and infant during a face-to-face situation. The IRSff validated for the Portuguese population, shows high internal consistency (Cronbach's alpha 0.91 (IRSff mother), 0.85 (IRSff infant)) high reliability, and concurrent and predictive validity (Figueiredo & Dias, 2013). This subscale was filled after viewing a 5 to 8-minute video of the mother-infant interaction, which was rated by two independent researchers previously trained. After their assessment, they met to discuss the items they disagreed on, i.e., items with a difference greater than 1 value. The average agreement in the total scale was 87.9%, and on each subscale, items ranged from 57% to 100%, with the highest disagreement found on the infant subscale item, which concerns the "Play Behavior" item. After this meeting, the video of the interaction was watched again in order to reach an agreement, in case of difficulty in reaching a decision a third researcher was consulted. After that, its congruence was assessed once more, and the total sum regarding the mother and infant scale was made based on the average of the raters' scores. FACE-TO-FACE MOTHER-INFANT INTERACTION: DIFFERENCES BETWEEN DEPRESSED AND NON-DEPRESSED MOTHERS AND ACCORDING TO THE INFANT'S SEX 15 Statistical analysis In order to analyze (1) the differences in face-to-face mother-infant interaction between depressed mothers and non-depressed mothers, and (2) between the male infants and female infants, the same statistical analysis was conducted. Independent Samples T-Tests were performed on the full scale of motherinfant interaction, a Multivariate Analysis of Variance (MANOVA) was performed to analyze the subscale of mother interactive behavior and the subscale of infant interactive behavior, a MANOVA analysis was performed to analyze the specific items of the mother's interactive behavior, and a MANOVA analysis was performed to analyze the specific items of the infant's interactive behavior. All statistical analyses were performed using the 28th version of the IBM® SPSS® (Statistical Package for the Social Sciences) software, with a test’s significance level p-value probability of < .05. All variables were previously tested and followed the normal distribution. Results Table 2 shows the descriptive analyses of mother interactive behavior, infant interactive behavior, and mother-infant interaction at three months postpartum on the IRSff scores. The items whit the highest mean was “State” in both mother (M=2.85, SD=0.29) and infant (M=2.87, SD=0.34) subscales. The lowest mean was relative to the “Silence on the aversion to looking” in the mother’s subscale (M=1.48, SD=0.74) and to the “Deviation of the mother's direction” (M= 1.51, SD=0.67) in the infant subscale. The items with the highest variance were the “Silence on the aversion to looking” in the mother’s subscale (DP= 0.74) and the “Gaze Aversion” in the infant’s subscale (DP= 0.82). On the other hand, in both the mother and the infant subscales, the item "State" had the lowest variance (DP=0.29; DP=0.34, respectively). FACE-TO-FACE MOTHER-INFANT INTERACTION: DIFFERENCES BETWEEN DEPRESSED AND NON-DEPRESSED MOTHERS AND ACCORDING TO THE INFANT'S SEX 16 Table 2. Descriptive statistics of face-to-face mother-infant interaction M SD Minimum Maximum Mother interactive behavioritems 2.38 0.30 1.65 2.90 State 2.85 0.29 2 3 Significant physical activity 2.51 0.58 1 3 Head deviation 2.75 0.51 1 3 Eye contact 2.28 0.73 1 3 Facial expression 2.60 0.51 1.5 3 Meaningful Vocalization 2.49 0.55 1 3 Silence on the aversion to looking 1.48 0.74 1 3 Contingent response 2.57 0.52 1 3 Infantilized behavior 2.25 0.51 1.50 3 Gaming behavior 1.99 0.72 1 3 Infant interactive behavioritems 2.27 0.31 1.60 2.90 State 2.87 0.34 1.50 3 Significant physical activity 2.06 0.61 1 3 Atypical physical activity 2.73 0.48 1 3 Deviation of the mother's direction 1.51 0.67 1 3 Eye contact 2.65 0.61 1 3 Gaze Aversion 2.02 0.82 1 3 Facial expressions 2.36 0.58 1 3 Positive Vocalizations 2.06 0.74 1 3 Negative Vocalizations 2.45 0.67 1 3 Gaming behavior 1.98 0.63 1 3 Mother-infant interaction 2.32 0.28 1.70 2.90 FACE-TO-FACE MOTHER-INFANT INTERACTION: DIFFERENCES BETWEEN DEPRESSED AND NON-DEPRESSED MOTHERS AND ACCORDING TO THE INFANT'S SEX 17 Differences in face-to-face mother-infant interaction between depressed mothers and nondepressed mothers in the postpartum period Results of the independent samples T-Test did not reveal significant differences in the face-to-face mother-infant interaction between depressed and non-depressed women in the postpartum period (t(61)= 1.554, p =.125). The MANOVA including the mother and the infant subscales scores showed that there were no significant differences in the subscales of the mother and infant’s interactive behaviors [Λ = 0.962; F(2, 60) = 1.189; p = .312] between depressed and non-depressed women (Table 3). The MANOVA including the mother’s interactive behavior items [Λ = 0.814; F(10, 52) = 1.185; p = .322], showed that there were significant differences in the item “Significant physical activity” (Z= 5.552, p= .022) and the item “Facial Expression” (Z= 4.328, p= .042). Depressed mothers had less significant physical activity regarding their baby (M=2.24; SD=0.62) compared to non-depressed mothers (M=2.61; SD=0.54), and less positive facial expressions (M=2.38; SD=0.52) in interacting with their infants compared to non-depressed mothers (M=2.67; SD=0.48). The MANOVA including the infant’s interactive behavior items did not show significant differences according to the mother's depression status [Λ = 0.828; F(10, 52) = 1.081; p = .394] (Table 4). Table 3. Mother and infant interactive behavior scores in depressive mothers (EPDS ≥ 7) and non-depressive mothers (EPDS < 7) Depressive Mothers Non-depressive Mothers Z p n=17 n=46 M SD M SD Mother interactive behavior 2.29 0.27 2.41 0.31 1.96 .167 Infant interactive behavior 2.18 0.32 2.30 0.30 2.09 .153 FACE-TO-FACE MOTHER-INFANT INTERACTION: DIFFERENCES BETWEEN DEPRESSED AND NON-DEPRESSED MOTHERS AND ACCORDING TO THE INFANT'S SEX 18 Table 4. Mother and infant interactive behavior items in depressive mothers (EPDS ≥ 7) and non-depressive mothers (EPDS < 7) Depressive mothers Non-depressive mothers Z p n=17 n=46 M SD M SD Mother interactive behavioritems State 2.79 0.25 2.87 0.31 0.82 .368 Significant physical activity 2.24 0.62 2.61 0.54 5.55 .022 Head deviation 2.76 0.50 2.75 0.51 0.01 .920 Eye contact 2.18 0.83 2.32 0.70 0.44 .510 Facial expression 2.38 0.52 2.67 0.48 4.33 .042 Meaningful Vocalization 2.38 0.54 2.52 0.56 0.78 .379 Silence on the aversion to looking 1.44 0.70 1.49 0.76 0.05 .822 Contingent response 2.50 0.50 2.60 0.53 0.43 .514 Infantilized behavior 2.20 0.53 2.26 0.50 0.14 .706 Gaming behavior 2.00 0.77 1.99 0.71 0.00 .958 Infant interactive behavioritems State 2.79 0.44 2.90 0.29 1.29 .260 Significant physical activity 1.82 0.73 2.14 0.54 3.51 .066 Atypical physical activity 2.70 0.50 2.74 0.48 0.06 .810 Deviation of the mother's direction 1.50 0.66 1.51 0.69 0.00 .955 Eye contact 2.53 0.72 2.70 0.57 0.91 .344 Gaze Aversion 1.88 0.84 2.08 0.82 0.69 .410 Facial expressions 2.15 0.68 2.44 0.53 3.38 .071 Positive Vocalizations 2.03 0.82 2.08 0.71 0.05 .826 Negative Vocalizations 2.41 0.80 2.47 0.63 0.08 .773 Gaming behavior 1.97 0.82 1.99 0.55 0.01 .918 FACE-TO-FACE MOTHER-INFANT INTERACTION: DIFFERENCES BETWEEN DEPRESSED AND NON-DEPRESSED MOTHERS AND ACCORDING TO THE INFANT'S SEX 19 Differences in face-to-face mother-infant interaction between the sex of the infant (females vs males) The independent samples T-Test did not reveal significative differences in the face-to-face motherinfant interaction according to the sex of the infant T(61)= -1.557; p = .125. The MANOVA including the mother and infant’s interactive behaviors subscales showed that there were no differences according to the gender of the infant [Λ = 0.942; F(2, 60) = 1.859; p = .165 (Table 5). The MANOVA including the mother’s interactive behavior items [Λ = 0.844; F(10, 52) = 0.958; p = .490] did not show significative differences according to the sex of the infant. The MANOVA including the infant’s interactive behavior items did not reveal significative differences between males and females [Λ = 0.809; F(10, 52) = 1.229; p = .295], still, the subsequent univariate ANOVAs, show that there were significant differences in the item “Deviation of the infant's head” (Z= 4.906; p= .031) and a marginally significant difference in the item “Gaze aversion” (Z= 3.873; p=.054). Females were more likely to look away from their mother (M=1.33, SD=0.56) and avoid eye contact with her (M=1.83, SD=0.84) compared to the males (M=1.69, DP=0.74; M=2.22, DP=0.76, respectively) (Table 6). Table 5. Mother and infant interactive behavior in male infants and in female infants Males Females Z p n=31 n=32 M SD M SD Mother interactive behavior 2.41 0.31 2.34 0.29 0.94 .337 Infant interactive behavior 2.34 0.32 2.20 0.28 3.58 .063 FACE-TO-FACE MOTHER-INFANT INTERACTION: DIFFERENCES BETWEEN DEPRESSED AND NON-DEPRESSED MOTHERS AND ACCORDING TO THE INFANT'S SEX 20 Table 6. Mother and infant interactive items behavior in male infants and in female infants Males Females Z p n=31 n=32 M SD M SD Mother interactive behavioritems State 2.85 0.29 2.84 0.30 0.02 .882 Significant physical activity 2.53 0.59 2.48 0.57 0.11 .745 Head deviation 2.74 0.51 2.76 0.51 0.03 .855 Eye contact 2.40 0.74 2.16 0.72 1.81 .184 Facial expression 2.50 0.55 2.69 0.45 2.20 .143 Meaningful Vocalization 2.50 0.62 2.47 0.49 0.05 .825 Silence on the aversion to looking 1.64 0.82 1.31 0.63 3.27 .075 Contingent response 2.58 0.52 2.56 0.54 0.02 .892 Infantilized behavior 2.29 0.53 2.20 0.49 0.46 .499 Gaming behavior 2.08 0.71 1.91 0.73 0.92 .341 Infant interactive behavioritems State 2.89 0.28 2.86 0.38 0.11 .746 Significant physical activity 2.03 0.72 2.08 0.49 0.09 .768 Atypical physical activity 2.81 0.28 2.66 0.61 1.54 .219 Deviation of the mother's direction 1.69 0.74 1.33 0.56 4.91 .031 Eye contact 2.66 0.64 2.64 0.60 0.02 .895 Gaze Aversion 2.22 0.76 1.83 0.84 3.87 .054 Facial expressions 2.39 0.67 2.34 0.50 0.09 .771 Positive Vocalizations 2.19 0.73 1.94 0.74 1.92 .170 Negative Vocalizations 2.50 0.75 2.41 0.59 0.30 .583 Gaming behavior 2.05 0.64 1.92 0.62 0.63 .429 FACE-TO-FACE MOTHER-INFANT INTERACTION: DIFFERENCES BETWEEN DEPRESSED AND NON-DEPRESSED MOTHERS AND ACCORDING TO THE INFANT'S SEX 21 Discussion A central goal of this research was to better understand in which ways the presence of postnatal depression and the infant’s sex had an impact on the face-to-face mother-infant interaction 3 months after birth. Previous literature has found that the presence of these factors can influence the quality of face-to-face mother-infant interaction. So, relative to the face-to-face mother-infant interaction between depressed and non-depressed mothers the results of this study did not reveal significant differences. These findings are contrary to the results found in the studies of Binda et al. (2019) and Lovejoy et al. (2000). Yet, the results are in line with the study of Campbell et al (1995), which according to this: “In a relatively low-risk, community sample of first-time mothers, a diagnosis of depression in the postpartum period is not necessarily associated with less optimal mother-infant interaction” (Campbell et al., 1995, p. 7). Additionally, another possible explanation for the absence of significant results in the present study is that the number of infants with depressed and nondepressed mothers is quite different, which creates an imbalance in the two groups, which may have an impact on the statistical analysis. Although no differences were found in the mother interaction subscale, we found conclusive effects on the mother’s interactive behavior items, namely in the mother’s significant physical activity and the mothers’ facial expressions, which means that depressive mothers are more intrusive or indifferent to their infant's needs and tend to reveal more expressions of anger or indifference. These results of the mother’s items interactive behavior are in line with the existing literature, which reports that mothers who have postnatal depression are less responsive to their infant’s needs (Bernard et al., 2018; Binda et al., 2019), leading to the establishment of intrusive and hostile interactions (Crugnola et al., 2016; Murray et al., 2018). Concerning the interactive behavior of the infant, we did not find significant results either in the infant subscale or in the respective items, which means infants of depressive and non-depressive mothers show similar behaviors in their interaction with their mothers. These results are consistent with Stanley et al. (2004) findings that maternal postnatal depression does not determine the infant's behavioral response, a possible justification for this finding can be the biological constitution of the infants. This means that they can have FACE-TO-FACE MOTHER-INFANT INTERACTION: DIFFERENCES BETWEEN DEPRESSED AND NON-DEPRESSED MOTHERS AND ACCORDING TO THE INFANT'S SEX 22 certain characteristics in their temperament (e.g., reactivity and self-regulation) that may help them to respond effectively to their mother, even when the quality of the interaction is poorest. This research did not find significant results of the sex of the infant on the face-to-face mother-infant interaction. Although there is some speculation that there are differences in the quality of face-to-face motherinfant interaction between the sex of the infant, there are notable inconsistencies in the literature. Some studies show that the infant’s sex influences the face-to-face mother-infant interaction (e.g., Else-Quest et al., 2006; Malatesta & Haviland, 1982; Hsu & Fogel, 2003), while others show no differences (e.g., Kosiak, 2013; Moszkowski, 2004). Our results regarding the influence of the infant's sex on face-to-face mother-infant interaction are in line with Kosiak's (2013) and Moszkowski's (2004) study which showed that sex had no impact on mother-infant interaction. Furthermore, the mother's interactive behavior, whether in the subscale or in the respective items did not change significantly according to the sex of the infant, which is in line with Carter et al. (1990) who found that the way mothers interact with their infant is similar in males and females. It is important to emphasize that, although no differences were found in the infant interaction subscale, we found significant differences in the interactive behavior items according to the sex of the infant, namely on the item “Deviation from the mother's head orientation” and marginally on the item “Gaze Aversion”. In these items, the females had a lower score than the males, which means that female infants tend to avoid more looking at their mothers. Thus, these findings suggest that infant males have better interaction with their mothers, which means that the sex of the infant affects the quality of face-to-face motherinfant interaction. The obtained results in the infant’s interactive behavior are consistent with the study of Weinberg et al. (1999) who showed that males are more socially oriented and more likely to look at their mothers than females and also in accordace with the study of Braungart-Rieker et al. (1998), who found that female infants are more oriented to objects than males. These results can be explained by the fact that infant males experience greater difficulty to self-regulate their affective states, so they search for their mother's help to facilitate it (Friedman, 2005; Weinberg et al., 1999). FACE-TO-FACE MOTHER-INFANT INTERACTION: DIFFERENCES BETWEEN DEPRESSED AND NON-DEPRESSED MOTHERS AND ACCORDING TO THE INFANT'S SEX 23 Limitations and strengths In this study, certain limitations should be considered in the interpretation of the results found and in future research. The first limitation is the size of the sample, which is small and should be enlarged in further studies in order to enhance the statistical power and the external validity of the results. Second, the presence of a stranger filming the interaction, even if in a position of minimal interference, may have interfered with the quality of the recorded interaction. Notwithstanding, the fact that this condition is the same for both groups minimizes the bias (Eirinaki, 2022). Yet, to solve this limitation, it would be better in future studies for the mother to be asked to use the phone to record her interaction with her infant when they were both alone at home so that there is a more natural environment for both. Moreover, the results found are not able to be generalized, since the sample is not representative. For this reason, the generalization of these results should be taken with caution, even for the Portuguese population. This study included the strength of being a longitudinal study, having 4 points of maternal depression evaluation, being screened by the EPDS, during the third trimester of pregnancy (30 to 34 weeks gestation), 2 days, 2 weeks, and 3 months after birth. The EPDS is an internationally used screening tool, which is reliable and validated for the Portuguese population and allows to detection of cases of clinically significant symptoms with good accuracy. This way this periodic evaluation allows the reliable identification of depression development. Furthermore, the use of the IRSff is very reliable and meticulous for understanding motherinfant interaction, since it evaluates the mother’s and infant’s behavior, avoiding overgeneralizing and misinterpreting the existing differences. In addition, the instruments used in this research, in particular EPDS and IRS, have high internal consistency. Implications for clinical practice and research The study of face-to-face interaction is a novelty in science, and therefore it can be further developed. It is important to consider the difficulties mothers find in face-to-face interactions to create programs to help them be more sensitive and responsive toward their infants. Additionally, it is also important to create/insert pregnant women in maternity preparation programs in order to prevent the development of postpartum depression and consequently create better mother-infant interactions. It is also important to provide FACE-TO-FACE MOTHER-INFANT INTERACTION: DIFFERENCES BETWEEN DEPRESSED AND NON-DEPRESSED MOTHERS AND ACCORDING TO THE INFANT'S SEX 30 Appendix Approval of the Ethics Committee of The University of Minho