Association Between Persistent Maternal Depression among Japanese New Mothers and their Toddlers’ Behaviors

TL;DR

The study finds that ongoing maternal depression in Japanese mothers is linked to negative behaviors in their toddlers, such as poor sleep and hyperactivity.

Contribution

The study identifies persistent maternal depression as a significant predictor of toddler behavioral issues and parenting challenges.

Findings

Persistent maternal depression was associated with toddler sleep, eating, and physical activity issues.

Persistent maternal depression was linked to smartphone overuse and hyperactivity-like symptoms in toddlers.

Parenting emotions and abusive behaviors were more common in mothers with persistent depression.

Abstract

To determine the association between mothers’ persistent maternal depression and their toddlers’ behavior.

Online surveys were conducted twice with mothers who gave birth to their first child between March and June 2020. The survey periods were November 2020 and May–June 2022. Measures included baseline characteristics and family environment factors, maternal postpartum depression (Edinburgh Postnatal Depression Scale [EPDS]), maternal lifestyle and mother-reported toddler behaviors, and Internet/media use. Statistical analysis was performed using the χ² test, trend test, and logistic regression.

Of the 339 participants, 82 (24.1%) were in the “persistent maternal depression” group with high EPDS scores (≥ 9 points) at both time points, and 178 (52.5%) were in the “no maternal depression” group with low EPDS scores (< 9 points) at both time points. Persistent maternal depression was associated with sleep, eating behavior, physical activity, parenting emotions, and abusive behavior of mothers. Furthermore, persistent maternal depression may be related to undesirable toddler behaviors such as smartphone overuse and hyperactivity-like symptoms.

The persistence of postpartum depression is influenced by factors such as mothers’ parenting emotions. Preventing and supporting maternal depression in mothers can foster favorable behaviors in toddlers. In Japan, enhanced individualized, ongoing support for postpartum mothers, tailored in duration and form, could promote both maternal well-being and positive parenting practices.

Full text

Introduction

Toddlerhood is an important period of remarkable growth and development, both physically and mentally, during which the foundation of one’s personality is laid. Lifestyle behaviors such as eating, sleeping, exercising, and playing greatly influence development during this period. In Japan, the environment surrounding children has changed dramatically with the declining birth rate and the shift to nuclear families. Furthermore, the COVID-19 pandemic has highlighted new issues such as increased sedentary time, use of media devices, and other diversifying behaviors among children (López-Bueno et al., 2021). In particular, the COVID-19 pandemic was associated with an increased prevalence of overweight Japanese elementary school students in a study conducted in Tokyo, Japan, highlighting, among other things, a decrease in physical activity (Kawahara et al., 2024). These changes have been observed in all generations, including pregnant women, mothers, and toddlers, and have a negative impact on toddlers’ health-related behaviors, leading to worsening physical and mental health (Androutsos et al., 2021; López-Bueno et al., 2020, 2021).

The health of toddlers is greatly affected by their environment and family behavior, especially in the home. In Japan, the burden of housework and childcare is still disproportionately placed on mothers, although awareness of gender equality is progressing with an increase in the number of dual-earner households. According to a Japanese survey, mothers in Japan spend approximately 2.1 − 3.6 times as much time as fathers do on housework and childcare (Cabinet Office, 2020). Furthermore, multiple studies on the impact of mothers’ lifestyles on toddlers’ health have shown lifestyle transfers between parents and toddlers (Wang et al., 2022; Larsen et al., 2015). In general, maternal behaviors such as healthy eating and proper sleep habits play an important role in supporting mothers’ mental health and toddlers’ healthy growth.

The mother’s lifestyle, in addition to its impact on the toddler, is closely related to the mother’s own physical and mental health. Maternal depression is widely recognized as a common health problem faced by postpartum mothers worldwide and is attributed to lifestyle and environmental factors such as lack of sleep and social support, and can last for months or years (Lin et al., 2018; National Institutes of Health (NIH 2020). In the United Kingdom (Barker et al. 2012), Australia (Woolhouse et al., 2015), Canada (Wickham et al., 2015), and France (van der Waerden et al., 2015), studies have reported that 10–30% of mothers experience persistent maternal depression. Previous studies have shown that toddlers raised by mothers with persistent maternal depression experience emotional and behavioral difficulties (Giallo et al., 2015) and that persistent maternal depression is significantly associated with children’s psychological problems (Tainaka et al., 2022).

However, globally, there is limited research on how maternal depression specifically impacts toddler behavior, and further investigation in this area is needed. Therefore, the purpose of this study is to clarify the association between persistent maternal depression and toddler behavior in Japan. By elucidating the relationship between maternal mental health and infant development, this study provides a foundation for proposing specific measures to support the healthy development of toddlers.

Methods

Research Design and Duration

This was a longitudinal study with an online descriptive questionnaire survey administered in Japan. We conducted two surveys: the first from November 26 to 30, 2020 and the follow-up from May 26 to June 26, 2022.

Sample Selection

Participants comprised mothers who gave birth to their first child between March and June 2020 and were registered respondents (1.3 million) of Macromill, Inc. (Tokyo, Japan), an Internet research company. The first screening randomly selected approximately 40,000 people who met the following eligibility criteria: (1) aged 18–44 years, (2) female, (3) married, and (4) with a child. For the second screening, eligibility criteria were based on raising a first child between 5 and 8 months postpartum and owning a smartphone. Participants were emailed the research outline, and were asked to review the eligibility and instructions and confirm their consent to participate. A total of 771 participants responded to the first survey. The follow-up survey was conducted one and a half years later and yielded 344 responses (44.6% response rate). Notably, this survey excluded mothers who gave birth to twins, did not give birth themselves (e.g., adoption), were not living with their toddler, and were unable to respond in Japanese.

Measures

Measures assessed (1) basic attributes and family environment factors, (2) maternal depression, (3) lifestyles of mothers and mother-reported toddler behavior, and (4) Internet/media use. These variables were assessed in the second survey.

Basic Attributes and Family Environment

Participants were asked to respond to questions regarding age, employment status, family structure, daytime childrearing status, average daily hours of childrearing time, and rest time to ascertain their living conditions. Additionally, the participants were asked about their feelings regarding childrearing (whether they felt relaxed and confident in their childrearing) and abuse-suspect behaviors, such as hitting the child.

Maternal Depression

The Japanese version of the Edinburgh Postnatal Depression Scale (EPDS) was used to assess maternal depression in mothers (Cox et al., 1987; Okano, 1996). The EPDS has been used with mothers during pregnancy and several years postpartum (Netsi et al., 2018; Paul & Pearson, 2020). The Japanese version of the EPDS has adequate reliability with Cronbach’s α = 0.78, sensitivity of 0.75, and specificity of 0.93 when the cutoff is set at 9 points (Okano, 1996).

The EPDS was utilized in both the first and second surveys. Participants who scored < 9 in both surveys were defined as the “no maternal depression” group, and those who scored ≥ 9 in both surveys were defined as the “persistent maternal depression” group.

Lifestyles of Mothers and Mother-Reported Toddler Behavior

Based on previous studies, participants were asked about their own and their toddlers’ diets, physical activity, and sleep status (National Institute of Health and Nutrition, 2012; Ministry of Agriculture, Forestry and Fisheries, 2021; National Center for Child Health and Development, 2018). Some of these data were continuous, but were reclassified.

The Japanese version of the Athens Insomnia Scale (AIS) was administered to the participants. The AIS is a universal measure of insomnia developed by the Global Project on Sleep and Health, an initiative of the World Health Organization (Soldatos et al., 2000). Scores are quantified, with a maximum of 24 points to measure the degree of insomnia objectively. The AIS has been proven reliable and valid in healthy adults (Okajima et al., 2013).

Participants were also asked about their toddler’s health status and developmental indicators. Based on the project and a health checkup guide, we asked about the child’s progress at 18 months according to developmental milestones (National Center for Child Health and Development, 2018; Ministry of Health, Labour and Welfare, 2015) and history of health checkups. To obtain accurate results, participants were asked to refer to the Maternal and Child Health Handbook, which is distributed to all pregnant women in Japan and contains records of medical checkups and vaccinations by medical institutions and parents, as well as official records from medical institutions and government agencies.

Internet/Media Use

Participants were asked about their own and their child’s average daily hours of Internet/media use during the past week by type of device (smartphone, tablet, or TV). Participants were referred to the “weekly report function” on their smartphones to retrieve actual usage data. The “weekly report function” is a default feature on smartphones that records the time spent in operation. A simple operation shows, for example, the average screen time spent on the smartphone and each application over the previous week. External validity was reinforced by using this function and providing a supplementary explanation of how to operate it during data collection. We inquired about their usage of the Internet/media before going to bed.

Analysis

Participant Analysis

Of the 344 participants in the first and second surveys, excluding those who were not living with their toddlers, data from 339 participants (valid response rate: 98.5%) were included in the analysis.

Statistical Analysis

The χ^²^ test and trend test (Mantel-Haenszel test) confirmed the association between persistent maternal depression and lifestyle. Furthermore, a logistic regression analysis was conducted with toddler’s behavior as the dependent variable, persistent postpartum depression as the independent variable, and age and employment as the adjusted variables. For all tests, p < 0.05 was considered statistically significant. SPSS Statistics version 27.0 for Windows (IBM Corp., Armonk, NY, USA) was used for the analysis.

Results

Of the 339 participants, 82 (24.1%) were in the persistent maternal depression group with high EPDS scores (≥ 9 points) on both occasions, and 178 (52.5%) were in the no maternal depression group with low EPDS scores (< 9 points) on both occasions. The EPDS scores of the others (n = 79, 23.3%) fluctuated between being above and below 9 points. EPDS scores averaged 8.354 (standard deviation = 4.065) in the first survey and 6.558 (standard deviation = 4.968) in the second survey.

Persistent maternal depression was significantly different based on the mothers’ lifestyle elements of sleep (AIS, sleep duration), eating behavior (not eating three meals per day, adequate amount of food), physical activity (moderate to vigorous exercise), abuse-suspect behaviors, and parenting emotions (caring for toddler with a relaxed attitude, confidence in parenting; Table 1).

Table 1. Association between mothers’ lifestyles and presence of persistent postpartum depression in mothersTotal(n = 260)Persistent postpartum depressionPersistent postpartum depression group (n = 178)No postpartum depression group (n = 82)Mothers’ lifestyles at 2 years old n % n % n %P valueBasic attributesAge< 35 years18470.80%12771.30%5769.50%0.762 a≥ 35 years7629.20%5128.70%2530.50%EmploymentNot working12146.50%8346.60%3846.30%0.966 aWorking13953.50%9553.40%4453.70%SleepAIS-J< 3 points9837.10%9150.60%78.30%< 0.001 *a< 0.001 *b4 − 5 points4517.00%3117.20%1416.70%≥ 6 points12145.80%5832.20%6375.00%Sleep duration< 5 h3814.60%1810.10%2024.40%0.010 *a0.010 *b5–8 h19976.50%14380.30%5668.30%≥ 8 h238.80%179.60%67.30%MealsThree meals per dayEvery day18370.40%14078.70%4352.40%< 0.001 *aNot every day7729.60%3821.30%3947.60%Adequate amount of foodEvery day15760.40%12268.50%3542.70%< 0.001 *aNot every day10339.60%5631.50%4757.30%Eat a well-balanced dietEvery day7328.10%5028.10%2328.00%0.995 aNot every day18771.90%12871.90%5972.00%Eat slowly at least once a dayEvery day8934.20%6234.80%2732.90%0.764 aNot every day17165.80%11665.20%5567.10%Take-out useLess than once per week7930.40%5631.50%2328.00%0.578 aMore than once per week18169.60%12268.50%5972.00%ActivityModerate to vigorous exercise habitsHaving4617.70%2413.50%2226.80%0.009 *aNone21482.30%15486.50%6073.20%Light physical activity habitsHaving14555.80%10156.70%4453.70%0.642 aNone11544.20%7743.30%3846.30%Internet/media useDuration of smartphone use< 1 h2710.40%1810.10%911.00%0.832 a≥ 1 h23389.60%16089.90%7389.00%Duration of tablet use< 1 h24594.20%17196.10%7490.20%0.061 a≥ 1 h155.80%73.90%89.80%Duration of TV use< 1 h12246.90%8648.30%3643.90%0.508 a≥ 1 h13853.10%9251.70%4656.10%EnvironmentDaily child care supportPresent3613.80%2312.90%1315.90%0.525 aNone22486.20%15587.10%6984.10%Parenting time by mother< 1 h20.80%10.60%11.20%0.467 a0.222 b1–2 h166.20%95.10%78.50%≥ 2 h24293.10%16894.40%7490.20%Relaxing time by mother< 1 h11142.70%7240.40%3947.60%0.221 a0.756 b1–2 h8633.10%6536.50%2125.60%≥ 2 h6324.20%4123.00%2226.80%Parenting behaviorExperiencing abuse-suspect behaviorsHaving9636.90%4726.40%4959.80%< 0.001 *aNone16463.10%13173.60%3340.20%Parenting emotionTreating children with a relaxed attitudeYes18972.70%14279.80%4757.30%< 0.001 *aNo259.60%84.50%1720.70%Neutral4617.70%2815.70%1822.00%No confidence in childcareYes12548.10%7039.30%5567.10%< 0.001 aNo7528.80%5933.10%1619.50%Neutral6023.10%4927.50%1113.40%= P < 0.05, a = χ² test P, b = trend test PAIS, Athens Insomnia Scale

Toddler behaviors associated with mothers’ persistent maternal depression were sleep (sleep duration and time to fall asleep), eating behaviors (not missing meals and eating slowly), indoor sitting time, smartphone use time, tablet use time, and hyperactivity-like symptoms (Table 2). A logistic regression analysis was conducted with toddler behavior as the dependent variable, persistent maternal depression as the independent variable, and age and employment as the adjusted variables. The results revealed that persistent maternal depression was associated with toddler spending more time on a smartphone/tablet (odds ratio [OR] = 1.757, 95% confidence interval [CI] = 1.319–2.340, and OR = 1.565, 95% CI = 1.123–2.179), device use before bedtime (OR = 1.316, 95% CI = 1.068–1.623), shorter sleep duration (OR = 1.699, 95% CI = 1.337–2.160), longer time to fall asleep (OR = 1.412, 95% CI = 1.133–1.760), not having three meals per day (OR = 1.458, 95% CI = 1.136–1.871), not eating slowly (OR = 1.251, 95% CI = 1.044–1.499), and hyperactivity-like symptoms (OR = 1.413, 95% CI = 1.176–1.697) (Table 3).

Table 2. Association between toddlers’ behaviors and presence of persistent postpartum depression in mothersTotal(n = 260)Persistent postpartum depressionPersistent postpartum depression group (n = 178)No postpartum depression group (n = 82)P valueToddlers’ behaviors at 2 years old n % n % n %SleepSleep duration< 8 h4416.70%179.40%2732.10%< 0.001 *a<0.001 *b8–12 h20376.90%15284.40%5160.70%≥ 12 h176.40%116.10%67.10%Time to fall asleep< 1 h21582.70%15687.60%5972.00%0.002 *a≥ 1 h4517.30%2212.40%2328.00%MealThree meals per dayEvery day22787.30%16391.60%6478.00%0.002 *aNot every day3312.70%158.40%1822.00%Adequate amount of foodEvery day16563.50%11866.30%4757.30%0.163 aNot every day9536.50%6033.70%3542.70%Eats a well-balanced dietEvery day10540.40%7341.00%3239.00%0.762 aNot every day15559.60%10559.00%5061.00%Eats slowly at least once a dayEvery day16161.90%11966.90%4251.20%0.016 *aNot every day9938.10%5933.10%4048.80%Drinks a sweet drinkLess than once per week7528.80%5732.00%1822.00%0.096 aMore than once per week18571.20%12168.00%6478.00%Physical activityOutdoor playing time per day< 30 min6725.40%3821.10%2934.50%0.065 a0.063 b30 min to 1 h9536.00%6938.30%2631.00%≥ 1 h10238.60%7340.60%2934.50%Indoor activity time per day< 30 min6123.10%3720.60%2428.60%0.273 a30 min to 1 h7929.90%5832.20%2125.00%0.407 b≥ 1 h12447.00%8547.20%3946.40%Indoor sitting time per day< 30 min5621.20%2715.00%2934.50%0.001 *a0.004 *b30 min to 1 h6926.10%5228.90%1720.20%≥ 1 h13952.70%10156.10%3845.20%Internet/media useDuration of smartphone use< 1 h23389.60%16994.90%6478.00%< 0.001 *a≥ 1 h2710.40%95.10%1822.00%Duration of tablet use< 1 h24293.10%17196.10%7186.60%0.005 *a≥ 1 h186.90%73.90%1113.40%Duration of TV use< 1 h11243.10%7743.30%3542.70%0.931 a≥ 1 h14856.90%10156.70%4757.30%Device use before bedtimeYes5019.20%2715.20%2328.00%0.014 *aNo21080.80%15184.80%5972.00%DevelopmentResults of 18 months health checkupNo problem25296.90%17497.80%7895.10%0.254 aOthers83.10%42.20%44.90%Speaks meaningful wordsNo155.80%95.10%67.30%0.468 aYes24594.20%16994.90%7692.70%ImitationNo51.90%31.70%22.40%0.681 aYes25598.10%17598.30%8097.60%Communicates by pointing fingersNo51.90%52.80%00.00%0.125 aYes25598.10%17397.20%82100.00%Turns around when calledNo41.50%31.70%11.20%0.777 aYes25698.50%17598.30%8198.80%Language comprehensionNo93.50%73.90%22.40%0.540 aYes25196.50%17196.10%8097.60%Gets nervous in unfamiliar placesNo3413.10%2111.80%1315.90%0.367 aYes22686.90%15788.20%6984.10%Hyperactivity-like symptomsNo17567.30%13374.70%4251.20%< 0.001 aYes8532.70%4525.30%4048.80%Walking aloneNo51.90%21.10%33.70%0.167 aYes25598.10%17698.90%7996.30%= P < 0.05, a = χ² test P, b = trend test P

Table 3. Association between toddlers’ behavior and mothers’ persistent postpartum depression (logistic regression analysis)Sleep durationDifficulty falling asleepThree meals per dayEating slowlyIndoor sitting timeSmartphone useTablet useDevice use before bedtimeHyperactivity-like symptomsOR(95%CI)OR(95%CI)OR(95%CI)OR(95%CI)OR(95%CI)OR(95%CI)OR(95%CI)OR(95%CI)OR(95%CI)Age0.329(0.127–0.852)*0.612(0.281–1.332)0.616(0.251–1.513)1.124(0.640–1.975)0.809(0.468–1.398)0.681(0.254–1.829)0.706(0.219–2.273)0.784(0.387–1.588)0.913(0.506–1.648)Employment3.625(1.638–8.024)*0.857(0.443–1.658)1.587(0.733–3.435)2.143(1.270–3.617)*0.469(0.284–0.775)*2.273(0.927–5.574)2.377(0.807–6.997)1.246(0.664–2.336)1.114(0.652–1.905)Persistent postpartum depression1.699(1.337–2.160)

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1.412(1.133–1.760)

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1.458(1.136–1.871)

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1.251(1.044–1.499)

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0.874(0.731–1.045)1.757(1.319–2.340)

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1.565(1.123–2.179)

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1.316(1.068–1.623)

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1.413(1.176–1.697)

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*logistic regression analysis　P < 0.05OR: Odds ratio, CI: Confidence intervalA logistic regression analysis was conducted with toddler behavior as the dependent variable, persistent postpartum depression as the independent variable, and age and employment as the adjusted variables

Discussion

A novel finding of this study is that persistent maternal depression was associated with toddler behavior. This supports previous studies that found an impact on the mental health of toddler raised by mothers with persistent maternal depression (Giallo et al., 2015; Tainaka et al., 2022). Persistent maternal depression was associated with mothers’ inability to relax and raise their toddler and with potentially abusive behaviors. It was also associated with hyperactivity-like symptoms, short sleep duration, and irregular eating habits in toddlers. Taken together, these findings suggest that maternal mental status, such as behaviors that raise suspicions of abuse during child rearing or negative maternal affect, may play a mediating role, affecting both the mother and the child and contributing to the child’s problem behaviors. A complex set of factors is implicated in persistent maternal depression, and these factors are thought to have a multilayered influence.

Persistent maternal depression was associated with toddler behavior. We confirmed the association between Internet use (more than 1 h of smartphone/tablet use per day), sleep (short sleep of fewer than 8 h), diet (not consuming three meals every day), and mothers’ persistent maternal depression. Associations between children’s sleep, diet, and other lifestyle factors and maternal depression have been previously reported (Gui et al., 2022; Schultz et al., 2020; Armitage et al., 2009), and our results confirm these findings. According to World Health Organization guidelines (World Health Organization, 2019), for 2-year-olds, it is important that they get 11–14 h of sleep, also noting the need to reduce their sedentary time and limit their screen time to not more than 1 h. Further, exercise and outdoor play among toddlers contribute to good sleep. Regarding diet, a recommendation in previous studies has been that toddlers eat three main meals a day (breakfast, lunch, and dinner) (Moding & Fries, 2020). Children who skipped breakfast had poorer diet quality and lower total intake (Ramsay et al., 2018), which was associated with higher cardiovascular disease mortality, and skipping meals was associated with higher all-cause mortality (Sun et al. 2022). Less sleep, skipping meals, and prolonged Internet use are undesirable lifestyle behaviors for toddlers. As infants and toddlers are still developing, their lifestyle is often determined by their parents. This suggests that the mother’s mental state may have a negative impact on the child’s lifestyle. Therefore, persistent maternal depression may lead to undesirable lifestyle habits in toddlers.

The highest OR for toddler behavior was for smartphone use time (OR=1.757, 95% CI = 1.319–2.340). In Japan, excessive smartphone use by children has been termed “smartphone neglect”; this phenomenon has become a concern due to its potential to hinder interpersonal and communication skills development in early childhood (Chotpitayasunondh & Douglas, 2018; Corkin et al., 2021; Nergiz et al. 2020). It has also been reported that strong parental depression leads to neglect and accelerates children’s smartphone dependence (Mun & Lee, 2021). Moreover, persistent maternal depression was found to be associated with hyperactivity-like symptoms in toddlers, possibly influenced by excessive screen time, which has been reported to trigger developmental disorder-related symptoms (Heffler et al., 2020). These findings suggest that maternal depression may indirectly affect toddlers’ nature (i.e., causing hyperactivity-like symptoms) through prolonged smartphone use and its consequences.

Persistent maternal depression was associated with parenting feelings, confidence, and abuse-suspect behaviors. Previous studies have already shown that temporary maternal depression after childbirth is correlated with self-efficacy and parenting stress (Schwartz et al., 2015). In addition to these factors, the present study showed that relaxed feelings and confidence in parenting were relevant. Furthermore, parenting emotion was found to be a factor associated not only with temporary but also persistent maternal depression. Additionally, 36.9% of participants reported abuse-suspect behaviors, such as emotional harm or covering the child’s mouth, consistent with national data. While occasional emotional reactions may occur, repeated abusive behaviors require intervention. Supporting maternal mental health through family cooperation and accessible services is crucial. Continuous, seamless support from pregnancy onward can promote long-term well-being for both mothers and toddlers. In Japan, efforts are underway to provide seamless support through ongoing assistance. However, there are some omissions. For example, support is not given to those who have not expressed a need for help. Nuclear families are common, and there is often no one to turn to. Even if someone is in need, it is sometimes difficult to identify or grasp such challenges and situations. We believe that it is necessary to create a system in which mothers can ask for help without hesitation, along with the creation of a community where they can support each other.

Taken together, these findings suggest that the mother’s mental state, including behaviors that raise suspicions of abuse and negative maternal feelings during child-rearing, may play a mediating role, affecting both the mother and the toddler and contributing to the toddler’s problematic behavior. A complex set of factors may be involved in persistent maternal depression, and these factors may have a multilayered influence.

Limitations

This study had several limitations. First, the survey used a recall-and-answer method, which may have introduced recall and social desirability biases. Second, the sampling may have been biased given that the participants were online survey respondents. The representativeness of the survey results and the potential bias were concerns due to the lack of information regarding the selection of survey participants and respondents. Third, maternal depression found in this study (based on the EPDS results) was higher than average, suggesting that the survey attracted relatively anxious mothers with infants. The reported impact of the non-face-to-face survey method and the COVID-19 pandemic on the parenting environment may have influenced these results as well (Gómez-Baya, D., Gómez-Gómez, I., Domínguez-Salas, S., Rodríguez-Domínguez, C., Motrico, Emma 2023). In particular, the COVID-19 pandemic has also been reported to be associated with the development of depressive and anxiety symptoms in mothers of infants and may have been an effect modification factor. Fourth, the follow-up response rate for the second survey was 44.6%, which was restricted by the low response rate and a small number of participants in the analysis; future studies need to examine long-term changes with large sample sizes. Additionally, as other environmental factors, the influence of fathers and other family members must be considered because they play a significant role in a child’s development. Finally, as the study was conducted in Japan, the results may not be applicable to other countries or cultures.

Conclusion

Factors associated with persistent postpartum depression and toddler behavior, including short sleep and hyperactivity-like symptoms, were identified. In addition, maternal parenting feelings were one of the factors associated with persistent postpartum depression, suggesting that this factor may lead to undesirable behavior in toddlers. Although support for postpartum mothers is available in Japan, it would be desirable to have more personalized choices with regard to the duration and forms of support needed and for these choices to be considered on an ongoing basis. This would also lead to desirable parenting behavior.