Pregnancy Cleaning Habits Linked to Lower Developmental Concerns in Japanese Children

Household dust is far more than an ordinary nuisance of domestic life. It is a complex reservoir of chemical and biological agents, ranging from phthalates and flame retardants to allergens, endotoxins, and microorganisms, all of which can accumulate on floors, bedding, and soft furnishings. Because pregnant women spend a substantial portion of their time indoors, the composition and management of the home environment during pregnancy has become an increasingly important question for researchers studying early child development. A new large-scale analysis from Japan now suggests that one of the simplest household practices, regular cleaning aimed at controlling house dust, may be associated with better developmental screening outcomes in children well beyond infancy.

The study, led by Specially Appointed Assistant Professor Kanako Shimada of the Toyama Regional Center for the Japan Environment and Children’s Study (JECS) at the University of Toyama, was conducted in collaboration with researchers from the university’s Department of Public Health. Drawing on data from 81,125 mother–child pairs enrolled in the Japan Environment and Children’s Study, a nationwide birth cohort, the team investigated whether maternal house dust–related cleaning behaviors during pregnancy were associated with child developmental screening results at 18 months, 2 years, 2.5 years, and 3 years of age. The findings were published online in the journal BMC Pediatrics on September 3, 2026.

The research builds on earlier work by the same group, which had identified an association between maternal cleaning behaviors during pregnancy and infant development up to 12 months of age. What remained unclear was whether that association persisted as children grew older, a period during which developmental trajectories begin to diverge more clearly and screening tools become more informative. Dr. Shimada explained the motivation behind the new analysis, noting that the previous study had found an association between maternal cleaning behaviors during pregnancy and child development up to 1 year of age, but that it remained unclear whether these associations extended beyond infancy. The team therefore examined the associations between these behaviors and developmental screening outcomes from 18 months to 3 years of age.

To capture house dust–related cleaning practices, mothers reported how often they vacuumed living-room floors and futons and how frequently they aired their futons during pregnancy. They also indicated whether they used anti-mite covers for their futons or bedding. These self-reported behaviors served as proxy indicators of household environmental management, reflecting the degree to which families took active steps to reduce dust and its associated components in the indoor environment. While such questionnaires cannot measure dust composition directly, they provide a practical way to characterize cleaning habits across a very large population.

Child development was assessed using the Japanese Ages and Stages Questionnaires, Third Edition (J-ASQ-3), a validated parent-completed screening instrument administered at 1.5, 2.0, 2.5, and 3.0 years of age. The questionnaire covers five developmental domains: communication, gross motor skills, fine motor skills, problem-solving, and personal–social behavior. Screening positive on any domain flags a child for further professional evaluation, making the J-ASQ-3 a widely used early-warning tool in pediatric and public health practice across Japan.

The statistical analysis employed generalized linear models to estimate adjusted odds ratios (AORs) for screening positive for developmental concerns at each assessment age. Two modeling strategies were used. Model 1 accounted for maternal factors, while Model 2 additionally adjusted for socioeconomic and dwelling environment factors, allowing the researchers to test whether the association survived after accounting for family circumstances that might independently influence both cleaning habits and child development.

The results showed a consistent pattern across all four assessment ages. Higher frequencies of house dust–related cleaning behaviors during pregnancy were associated with lower odds of screening positive for developmental concerns. In Model 1, adjusted odds ratios ranged from 0.74 to 0.97, and in the more fully adjusted Model 2 they ranged from 0.68 to 0.98. Importantly, the association appeared to be graded: the more frequently mothers engaged in cleaning-related behaviors, the progressively lower the odds that their children screened positive for developmental concerns at any of the measured time points. This dose-response pattern lends plausibility to the association, although it does not by itself establish causation.

The researchers are careful to frame these findings appropriately. The study did not directly measure house dust or environmental contaminants, so it cannot be determined whether the observed associations reflected reduced exposure to chemical contaminants, allergens, particulate matter, microbial components, or some other aspect of the indoor environment. The cleaning behaviors were used as proxy indicators of household environmental management, and the observed associations were modest, with adjusted odds ratios close to unity. Dr. Shimada emphasized that further research is needed to better understand the factors underlying these associations, and that studies using objective measures of the home environment will be particularly important in determining what may explain the observed patterns.

It is also essential to recognize that the findings demonstrate an association, not a causal relationship, between maternal cleaning behaviors and developmental screening outcomes. Differences in caregiving practices, general health-related behaviors, socioeconomic circumstances, postnatal environments, and other unmeasured factors may all contribute to the observed links. Families who clean more frequently may differ in numerous ways from those who clean less often, and some of these differences, rather than dust exposure itself, could account for the association. The researchers explicitly caution that the results should not be interpreted as evidence that cleaning itself directly reduces developmental risk.

Nevertheless, the study represents a meaningful extension of previous work by showing that maternal house dust–related cleaning behaviors during pregnancy were associated with developmental screening outcomes across multiple time points from 18 months to 3 years of age, a considerably longer window than earlier research had covered. The findings highlight household environmental management during pregnancy, including regular vacuuming, airing futons, and using anti-mite covers, as a potential area for further investigation. Looking ahead, the researchers call for studies incorporating objective environmental measurements, such as dust sampling or biomonitoring, as well as replication in diverse cultural and environmental settings, to clarify the underlying mechanisms and determine how generalizable these associations are. Until such evidence accumulates, the study stands as an intriguing observational signal from one of the world’s largest birth cohorts, pointing toward the indoor environment as a domain worthy of closer scientific scrutiny in the effort to understand the early-life determinants of child development.

Subject of Research: Association between maternal house dust–related cleaning behaviors during pregnancy and child developmental screening outcomes

Article Title: Maternal house dust–related cleaning behaviors during pregnancy associated with child developmental screening outcomes

Article References: Maternal house dust–related cleaning behaviors during pregnancy associated with child developmental screening outcomes. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: house dust, pregnancy, child development, developmental screening, J-ASQ-3, Japan Environment and Children's Study, birth cohort, vacuuming, indoor environment, observational study, BMC Pediatrics, public health