Impact of postpartum persistent depression on infant developmental behavior and maternal self-efficacy

Abstract

BACKGROUND

Postpartum depression (PPD) represents a significant public health concern, adversely affecting both new mothers and their infants. Despite routine early screening, PPD can persist beyond the initial postpartum months, with notably high incidence rates even one year after childbirth. Persistent PPD has been associated with poor developmental outcomes in infants, highlighting the need for continued monitoring and support during this critical period. Understanding the broader impacts of persistent PPD is essential for developing effective interventions to improve maternal and infant well-being.

AIM

To explore the impact of persistent PPD on infant developmental behavior and maternal self-efficacy.

METHODS

We recruited 60 postpartum women who experienced persistent depression after childbirth in our hospital from January 2020 to December 2024 as the research subjects. The study collected basic characteristics of both infants and mothers, analyzed the self-efficacy of the mothers and the developmental behaviors of the infants, and conducted a correlation analysis to examine the relationship between postpartum persistent depression in mothers and the developmental behaviors and self-efficacy of infants. The Bootstrap method was used to verify the significance of the mediating effect.

RESULTS

The basic characteristics of infants and mothers show that 53.33% are male, 58.33% are born via vaginal delivery, 88.33% have a normal body mass index, 51.67% are aged between 25 and 29 years, 70% are non-agricultural workers, 51.67% have a per capita household income over 4000 yuan, 96.67% are full-term births, and 58.33% of the fathers are aged between 26 and 32 years. In terms of infant development behavior, the gross motor skills score is relatively low (38.44 ± 12.15). Regarding maternal self-efficacy, the skill score (45.68 ± 5.49) and mental activity score (46.37 ± 3.72) are both at a low level. Correlation analysis reveals that postpartum persistent depression is significantly negatively correlated with maternal self-efficacy and infant development behavior (β = -0.439, -0.657, P < 0.001), while self-efficacy is positively correlated with infant development behavior (β = 0.728, P < 0.001). The path coefficient and Bootstrap method test indicate that self-efficacy acts as a mediator between postpartum persistent depression and infant development behavior, accounting for 54.80% of the effect (P < 0.05), while the direct effect of postpartum persistent depression on infant development behavior is 45.20% (P < 0.05).

CONCLUSION

Persistent PPD significantly negatively impacts infant developmental outcomes, with maternal self-efficacy serving as a partial mediator. These findings suggest that interventions targeting both depressive symptoms and self-enhancement may effectively promote infant health development.

Key Words: Postpartum women; Postpartum; Persistent depression; Baby; Developmental behavior; Self-efficacy

Core Tip: This study investigates the impact of persistent postpartum depression (PPD) on infant developmental behavior and maternal self-efficacy. Utilizing the Edinburgh Postnatal Depression Scale and Ages & Stages Questionnaires, Third Edition, we assessed 60 mother-infant dyads over a five-year period. Our findings reveal that persistent PPD significantly negatively impacts infant developmental outcomes, with maternal self-efficacy partially mediating this relationship. These insights underscore the necessity for targeted interventions addressing both depressive symptoms and enhancement of maternal self-efficacy to foster healthy infant development. This study enriches the understanding of developmental psychopathology and highlights potential targets for early intervention strategies.

INTRODUCTION

According to a report by the World Health Organization, approximately 10% of pregnant women and about 13% of those who have just given birth worldwide suffer from mental disorders such as depression. In some developing countries, this proportion is even higher, reaching 15.6%[1]. Postpartum depression (PPD) is a common mental disorder during the puerperium, characterized by symptoms such as low mood, diminished interest, and slowed thinking. In severe cases, it may even lead to suicidal tendencies, making it a significant public health issue. Research indicates that about 15%-20% of mothers do not experience natural relief from depressive symptoms within six months postpartum, with some cases persisting until the toddler stage (12-24 months of age)[2]. This not only harms the mother's mental health but may also impair the infant's cognitive and emotional development. Studies have shown that depressed mothers exhibit a 40% reduction in the frequency of positive facial expressions and an average decrease of 1.5 standard deviations in sensitivity scores, leading to ambiguous emotional signals received by infants[3]. This severely disrupts the establishment of mother-infant attachment and further affects the infant's emotional regulation ability, highlighting the significant impact of PPD on infant emotional control. Similarly, research suggests that children whose mothers experience depression for more than six months have an odds ratio of 2.1 (95%CI: 1.7-2.6) for developing behavioral problems[4]. However, whether this association emerges during infancy remains to be proven. Self-efficacy, defined as a mother's confidence in her caregiving abilities, has been shown by Frankham et al's research team[5] to modulate how mothers cope with parenting stress. Nevertheless, existing studies predominantly focus on short-term PPD, with limited attention paid to persistent maternal depression. It remains unclear whether prolonged PPD leads to low self-efficacy and high stress in mothers, thereby indirectly affecting infant behavioral development. Therefore, this study delves deeply into the impact of postpartum persistent depression on infant development behavior and self-efficacy. Unlike previous studies that only focused on direct effects, this study systematically explores the mediating mechanism of self-efficacy between persistent depression and infant development behavior for the first time, with the aim of improving the theory of developmental psychopathology and providing potential targets for targeted early intervention.

MATERIALS AND METHODS

General information

A total of 60 newborns and their mothers admitted to our hospital from January 2020 to December 2024 were selected as study subjects. The research has been approved by the hospital's ethics committee.

Inclusion criteria: (1) Mothers were clinically assessed as meeting the diagnostic criteria for persistent PPD based on the Pathophysiological Assessment of Postpartum Depression[6] and PPD diagnostic standards[7]; (2) Mothers had a single-term live birth at 37-42 weeks of gestation; (3) Maternal age ranged from 22 to 50 years; and (4) Participants and their legal guardians voluntarily signed informed consent.

Exclusion criteria: (1) Newborns with congenital developmental abnormalities or birth defects; (2) Mothers with severe neurological or other major organic diseases; (3) Adverse pregnancy outcomes or severe obstetric complications; (4) Mothers unable to cooperate due to physical illness or postoperative conditions; (5) History of antidepressant treatment; (6) Comorbid decompensated cardiovascular or cerebrovascular diseases; and (7) Cognitive or communication impairments.

Diagnostic criteria for persistent depression: The Edinburgh Postnatal Depression Scale (EPDS)[8] was the primary tool for assessing maternal depressive states in this study. Developed by Cox et al[8] in 1987, this scale consists of 10 items covering mood, anhedonia, and self-blame, with each item scored on a 0-3 scale (total score range: 0-30). Higher scores indicate more severe depressive symptoms. Based on literature standards, mothers exhibiting depressive symptoms at both 42 days and 3 months postpartum were classified as having "persistent PPD"[9]. The scale demonstrated good reliability and validity, with a Cronbach's α of 0.86.

Sample size calculation: According to the sample size calculation formula of n = [2 × (Zα/2 + Zβ)² × σ²]/δ², including Zα/2 for significance level corresponding value, namely the α = 0.05, Z = 1.96; Zβ represents the corresponding value of the test efficacy[10]. When β = 0.2 and the efficacy is 80%, Z = 0.84. σ represents the overall standard deviation, and δ represents the mean difference. Based on previous literature, it was calculated that at least 54 cases were needed[2]. Considering a 20% loss to follow-up rate, it was finally determined to include 60 parturients as the research subjects.

Data collection

Basic demographic and clinical data were collected, including: Maternal and paternal age, education level, household income per capita, and residence status (urban/rural); Maternal delivery method (vaginal/cesarean); Neonatal information (sex, gestational age, and birth weight).

Observation indicators: (1) Infant developmental behavior: The Ages & Stages Questionnaires, Third Edition (ASQ-3)[11] was used to assess infant development at 2 months of age. The questionnaire evaluates five domains: Communication, gross motor skills, fine motor skills, problem-solving, and personal-social abilities. Each domain consists of 6 items scored on a 3-point scale ("Yes" = 0, "Sometimes" = 5, "No" = 10), with total scores ranging from 0 to 60 per domain. Lower scores suggest a higher risk of developmental delay. The scale's Cronbach’s α coefficient exceeded 0.8; and (2) Maternal self-efficacy: The Breastfeeding Self-Efficacy Scale (BSES)[12] was used to assess mothers' confidence in their parenting abilities. The scale includes 30 items across two dimensions: Skill proficiency (15 items) and emotional adjustment (15 items). Each item is scored from 1 to 5, with higher total scores indicating stronger parenting self-efficacy. The scale's test-retest reliability was 0.811.

Quality control

(1) All researchers completed the unified scale usage training (EPDS, ASQ-3, BSES), and all researchers were required to pass the theoretical assessment and video evaluation consistency test (intraclass correlation coefficient > 0.85); (2) During the scale assessment, it was independently evaluated by two physicians who were unaware of the mother's depressive status, with a Kappa value > 0.75; and (3) Two-person back-to-back data entry was adopted, with logical verification set up. Outliers needed to be rechecked from the original records. After data collection, 15% of the samples were randomly cross-checked and retested, and the correlation coefficients within the groups were all greater than 0.90.

Statistical analysis

In this study, SPSS 27.0 and AMOS 21.0 statistical software were used for data analysis. Quantitative data were expressed as mean ± SD or median (interquartile range), while qualitative data were presented as frequency. Spearman correlation analysis was used to explore the relationships among variables, and a structural equation model was constructed based on AMOS 21.0. With social support as the predictor variable, parenting self-efficacy as the mediating variable, and PPD as the outcome variable, parameter estimation was conducted through the maximum likelihood estimation method. To control the influence of potential confounding variables such as family income and educational level on infant development behavior and maternal self-efficacy, in the structural equation model, confounding variables were included in the analysis as covariates, and their independent effects were evaluated through standardized path coefficients. The evaluation criteria for model adaptability are as follows: χ² degree of freedom ratio (χ²/df) < 5, GFI > 0.90, TLI > 0.90, RMSEA < 0.08, and SRMR < 0.08. The 95%CI of the mediating effect was calculated by sampling 5000 times with Bootstrap, and the common method bias analysis was conducted through the Harman univariate test. All statistical tests were considered significant with P < 0.05.

RESULTS

Basic characteristics of infants and mothers

The study included the basic characteristics of 60 infants and their mothers. The data showed that 53.33% were male infants; 58.33% were born via vaginal delivery; 88.33% had a normal body weight; the majority (51.67%) of the mothers were aged between 25 and 29; the majority (58.33%) of the fathers were aged between 26 and 32; 96.67% of the infants were full-term; the educational levels of the mothers and fathers were primarily at or above the bachelor's degree level, with 38.33% each; 51.67% of the families had an average annual income exceeding 4000 yuan, and 70.00% had non-agricultural household registration (Table 1).

Table 1 Basic characteristics of infants and mothers.

Characteristic variable	Classify	Number of cases (n = 60)	Composition ratio (%)
Gender	Male	32	53.33
	Female	28	46.67
Delivery method	Vaginal delivery	35	58.33
	Cesarean section	25	41.67
Birth weight	Low birth weight	1	1.67
	Normal birth weight	53	88.33
	Macrosomia	6	10.00
Maternal age at birth (years)	< 25	9	15.00
	25-29	31	51.67
	> 29	20	33.33
Paternal age at birth (years)	< 26	9	15.00
	26-32	35	58.33
	> 32	16	26.67
Term birth	Full-term infant	58	96.67
	Preterm birth	2	3.33
Maternal education level	High school or below	18	30.00
	College (associate degree)	19	31.67
	Bachelor's degree or above	23	38.33
Paternal education level	High school or below	18	30.00
	College (associate degree)	19	31.67
	Bachelor's degree or above	23	38.33
Per capita household income (yuan)	< 2500	7	11.67
	2500-4000	22	36.67
	> 4000	31	51.67
Account	Agricultural	18	30.00
	Non-agricultural	42	70.00

Maternal self-efficacy and infant developmental behavior scores

In the aspect of infant development behavior, gross score 38.44 ± 12.15 points, relatively low; In terms of parturient self-efficacy, the skill proficiency was 45.68 ± 5.49 points and the emotional adjustment was 46.37 ± 3.72 points, both of which were at a relatively low level (Table 2).

Table 2 Self-efficacy of parturients and developmental behavior of infants (points, mean ± SD).

Items		Score
Infant developmental behavior	Communication	51.38 ± 7.31
	Gross motor	38.44 ± 12.15
	Fine motor	46.68 ± 11.07
	Problem solving	48.51 ± 11.37
	Personal-social	41.59 ± 10.28
Maternal self-efficacy	Skill proficiency	45.68 ± 5.49
	Emotional adjustment	46.37 ± 3.72

The relationship between postpartum persistent depression of parturients and self-efficacy as well as the developmental behavior of infants

In the correlation analysis, postpartum persistent depression was significantly negatively correlated with parturient self-efficacy and infant development behavior (β = -0.439, -0.657, P < 0.001); Self-efficacy was positively correlated with infant developmental behavior (β = 0.728, P < 0.001; Table 3).

Table 3 Correlation analysis of persistent postpartum depression in parturients and infant development behavior and self-efficacy.

Project	Postpartum persistent depression	Infant developmental behavior	Maternal self-efficacy
Postpartum persistent depression	1	-	-
Infant developmental behavior	-0.657	1	-
Maternal self-efficacy	-0.439	0.728	1

Analysis of the mediating effect of self-efficacy between persistent PPD and infant development behavior

Taking postpartum persistent depression of parturients as the independent variable, infant development behavior as the dependent variable, and self-efficacy as the mediating variable, a structural equation model was constructed (Figure 1). The model fitting results show that the structural equation model fits well, as shown in Table 4. The model path coefficients show that postpartum persistent depression has a significant negative impact on infant development and behavior, while maternal self-efficacy has a positive guiding effect on infant development and behavior, as shown in Table 5. Bootstrap analysis revealed that the direct effect of postpartum persistent depression on infant development behavior was 45.20% (P < 0.05), and the indirect effect of self-efficacy between postpartum persistent depression and infant development behavior was 54.80% (P < 0.05), as shown in Table 6.

Figure 1 Analysis of the mediating effect of self-efficacy between postpartum persistent depression and infant development behavior.

Table 4 Fitting indicators of the structural equation model.

Fit indices	χ2/df	GFI	AGFI	NFI	RFI	IFI	TLI	CFI	RMSEA
Model values	2.539	0.928	0.931	0.959	0.962	0.908	0.941	0.937	0.065
Reference range	< 3	> 0.9	> 0.9	> 0.9	> 0.9	> 0.9	> 0.9	> 0.9	< 0.08

Table 5 Estimation results of the model path coefficients.

Path	Unstandardized path coefficient	Standardized path coefficient	SE	Critical ratio	P value
Persistent depression -self-efficacy	-0.159	-0.349	0.063	-2.524	0.012
Self-efficacy - infant developmental behavior	0.661	0.637	0.112	5.902	< 0.001
Persistent depression - infant developmental behavior	-0.257	-0.212	0.085	-3.024	0.002

Table 6 Bootstrap analysis of the significance test of mediating effects.

Effect type	Path	Effect value	Boot standard error	Boot CI lower limit	Boot CI upper limit	Effect proportion (%)
Total effect	Persistent postpartum depression - infant developmental behavior	-0.469	0.071	-0.608	-0.331	100
Direct effect	Persistent postpartum depression - infant developmental behavior	-0.212	0.085	-0.379	-0.045	45.20
Indirect effect	Persistent depression - self-efficacy - infant developmental behavior	-0.257	0.063	-0.381	-0.133	54.80

CI: Confidence interval.

DISCUSSION

In China, routine screening for PPD typically extends only until the end of the puerperium and rarely continues into the first postpartum year[13]. However, studies have reported[14] that while the incidence of PPD decreases as maternal hormone levels stabilize beyond the early postpartum period, it remains significantly elevated—9% to 11% higher than in the general population—even at one year postpartum. During this critical window, infant developmental behavior often lacks essential healthy guidance.

The general data of this study shows that the majority of parturients with persistent PPD are between 25 and 29 years old, the mode of delivery is natural delivery, the per capita income of the family is higher than 4000, the fetuses are delivered at full term, the body mass index is normal, and most of them have non-agricultural household registration. This indicates that modern women of childbearing age are facing excessive hidden pressure and insufficient attention to mental health. Meanwhile, the research results found that in the developmental behaviors of infants, communication, gross motor skills, fine motor skills, problem-solving, and personal and social scores were relatively low. Moreover, the scores of skills and inner activities in the self-efficacy of parturients were not high, indicating that depressed mothers had insufficient confidence in parenting and the infants growing up in the corresponding environment had poor developmental behaviors. The possible reasons are as follows: On the one hand, the conversation frequency between depressed mothers and their infants is not high, and the use of "infantile language" is less, resulting in a 12.7% reduction in the gray matter volume of the left temporal lobe of their infants at the age of 6 months[15]; On the other hand, the average prone time provided by depressed mothers was 11.2 minutes per day, resulting in a 55% decrease in the standard-raising rate of infants at the age of 4 months and severely inhibiting the activation of the infant motor cortex[16]; Moreover, the cortisol level in the breast milk of depressed mothers is higher. Since the serum cortisol of infants is negatively correlated with the gross motor development quotient (r = -0.51, P = 0.008), it further inhibits the muscle development of infants, resulting in delayed motor and vocal cord development in infants[17]; In addition, also because depressed mothers intervene on average within 2.3 seconds when their infants solve problems, the proportion of their infants with paradoxical attachment reaches 47%, and the social reference response is delayed by 400-600 ms[18]. Under the influence of all these negative effects, the developmental behaviors of infants are inhibited. Similar to the research results of Pan et al[19]. Persistent depression suppresses the behavioral activation system of mothers, making them more prone to underestimating their own abilities. They frequently fall into repetitive negative thinking of "I can't do it", consuming psychological resources and seriously affecting their physical and mental health. The investigation by Çankaya and Şimşek[20] supports the results of this study. However, the sample size in this study is relatively small, which can easily lead to bias in the research results. This is also a shortcoming of this study. Therefore, it is still necessary to further expand the sample size to improve the universality of the research results.

The research results show that infant development behavior and parturient self-efficacy are negatively correlated with postpartum persistent depression respectively, while there is a positive correlation between infant development behavior and parturient self-efficacy. This suggests that postpartum persistent depression inhibits infant development behavior and parturient self-efficacy, while parturient self-efficacy promotes infant development behavior. The reason for this is that the salivary cortisol level of depressed mothers increases by 42%. Due to the significant correlation between the cortisol concentration levels in the umbilical cord blood of mothers and infants (r = 0.61), the hippocampal neurogenesis of infants is inhibited, thereby reducing their memory and learning abilities[21]. Meanwhile, due to the circadian rhythm disorder of depressed mothers, the peak secretion of melatonin is delayed by 1.8 hours, causing infants to wake up 2.3 times more each night at night. Moreover, sleep quality is directly related to cognitive development, seriously affecting the growth and development of infants[22]. Moreover, the number of facial expression changes per hour for depressed mothers decreased by 40%, resulting in a 52% reduction in the eye contact response rate of 6-month-old infants. Due to insufficient input of social stimuli, it seriously hindered the behavioral development of infants[23]. When depressed mothers perform parenting tasks, the activation intensity of the dorsolateral area of the PFC decreases by 2.1 standard deviations, resulting in a 67% increase in the error rate of parenting plans and making mothers more likely to give up when facing parenting challenges[24]. In addition, the infants of depressed mothers smile only 8 times per hour. This negative feedback further weakens the mothers' confidence, resulting in a reduced sense of pleasure obtained from parenting behaviors[25]. More importantly, when a baby falls, the calm expression and verbal comfort of a highly efficient mother help the baby build a stress buffer system. This timely response helps the baby establish an internal cognitive model of "predictable world", promoting the development of its exploratory behavior. This physiological coordination can reduce the baby's stress response[26]. A number of foreign studies have confirmed the results of this study[27,28]. However, in this study, the dose-effect relationship between the duration of maternal depression and the long-term development of infants (such as language and cognitive abilities) was not tracked and evaluated. In the future, a longitudinal design needs to be further adopted, combined with standardized tools such as Bayley-III, to systematically investigate the cumulative effect of chronic depression on children's neurodevelopment, in order to provide a reference basis for relevant clinical treatment interventions.

Through the mediating effect test of the Bootstrap method, self-efficacy has a mediating effect between postpartum persistent depression and infant development behavior, with an effect proportion of 54.80%. The possible reason is that when PPD decreases, the secretion of oxytocin in mothers reduces, which in turn affects the establishment of the mother-infant attachment relationship and reduces the social mobility ability of infants[29]. On the other hand, mothers with high self-efficacy can still maintain basic interactions with their infants even when they are in a depressed state. This protective factor can alleviate the negative impact of depression on the development of infants to a certain extent[30]. However, since some data rely on self-evaluation by parents or children patients, there may be reporting bias, resulting in certain limitations of this study.

CONCLUSION

To sum up, there is a complex interactive relationship among postpartum persistent depression of parturients, infant development behavior and parturient self-efficacy. Postpartum persistent depression of parturients can not only directly affect infant development behavior, but also regulate infant development behavior through parturient self-efficacy. Therefore, the assessment of infant growth and development should combine the postpartum mental state of parturients and their self-efficacy. To enhance the overall effect.