Maternal cleaning habits during pregnancy reduce child developmental concerns

House dust can contain chemical and biological components, including phthalates, flame retardants, allergens, endotoxins, and microorganisms. Because pregnant women spend time indoors, household environmental conditions during pregnancy may be relevant to child development. Earlier research linked maternal cleaning behaviors with infant development up to 12 months, but evidence beyond the first year was limited. The researchers therefore examined whether these behaviors were associated with developmental screening outcomes from 18 months to 3 years of age.

To address this gap, a research team led by Specially Appointed Assistant Professor Kanako Shimada of the Toyama Regional Center for JECS at the University of Toyama, Japan, conducted the study in collaboration with researchers from the university's Department of Public Health. They analyzed data from 81,125 mother–child pairs participating in the Japan Environment and Children's Study, a nationwide birth cohort.

Mothers reported how often they vacuumed living-room floors and futons and aired futons during pregnancy, as well as whether they used anti-mite covers for their futons or bedding. Child development was assessed at 1.5, 2.0, 2.5, and 3.0 years using the Japanese Ages and Stages Questionnaires, Third Edition (J-ASQ-3), covering five developmental domains: communication, gross motor, fine motor, problem-solving, and personal–social. Generalized linear models were used to estimate adjusted odds ratios (AORs); Model 1 accounted for maternal factors, and Model 2 additionally accounted for socioeconomic and dwelling environment factors. Their findings were published online in the journal BMC Pediatrics on September 3, 2026.

Across all four assessment ages, higher frequencies of house dust–related cleaning behaviors were associated with lower odds of screening positive for developmental concerns. In Model 1, adjusted odds ratios ranged from 0.74 to 0.97, while Model 2 produced a range of 0.68 to 0.98. A graded association was observed, with higher frequencies of cleaning-related behaviors associated with progressively lower odds of screening positive for developmental concerns. "Our previous study found an association between maternal cleaning behaviors during pregnancy and child development up to 1 year of age. However, it remained unclear whether these associations extended beyond infancy," says Dr. Shimada. "We therefore examined the associations between these behaviors and developmental screening outcomes from 18 months to 3 years of age."

The findings may be relevant to household environmental management during pregnancy, particularly behaviors such as regular vacuuming, airing futons, and using anti-mite covers. However, the study did not directly measure house dust or environmental contaminants. The cleaning behaviors were used as proxy indicators of household environmental management, so the researchers could not determine whether the associations reflected reduced exposure to chemical contaminants, allergens, particulate matter, microbial components, or other aspects of the indoor environment. The observed associations were also modest, with adjusted odds ratios close to unity. "Further research is needed to better understand the factors underlying these associations. Studies using objective measures of the home environment will be particularly important in determining what may explain the observed associations," says Dr. Shimada.

Importantly, the findings show an association, not a causal relationship, between maternal cleaning behaviors and developmental screening outcomes.

Overall, the study extends previous findings 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. The results should not be interpreted as evidence that cleaning itself directly reduces developmental risk. Differences in caregiving, health-related behaviors, socioeconomic circumstances, postnatal environments, and other unmeasured factors may contribute to the associations. The researchers emphasize 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 generalizability.