Perinatal depression, which occurs during pregnancy or the postnatal period, is one of the most common mental health conditions experienced by women. This condition affects not only the health of the mother during pregnancy and after childbirth, but also the development of the child.
Multiple factors influence maternal mental health, and recently emerging evidence suggests a link between antibiotic use and maternal mental health. The study was published in the journal Volume 26. BMC public health It was conducted on January 10, 2026 by Kenta Matsumura, a former associate professor at the University of Toyama’s Department of Public Health and currently a professor at Aomori Prefectural University of Health and Welfare and co-researcher, and Dr. Hidekuni Inadera of the Toyama Unit Center of the Japan Environment and Children’s Research Center (JECS) at the University of Toyama.
“While there are situations in which antibiotics are essential, the emergence of antibiotic-resistant bacteria due to inappropriate use of antibiotics is a major concern. We wanted to understand how antibiotic use is associated with psychological distress in pregnant women.” I share Professor Matsumura as the inspiration behind my research.
To examine the relationship between antibiotic use and psychological distress, researchers analyzed data from 94,490 pregnant women enrolled in JECS, an ongoing national birth cohort study aimed at investigating how environmental factors are related to children’s health and development. Most of the women in this study were around 12 weeks pregnant, and follow-up assessments were done around 15 weeks pregnant.
Information on participants’ antibiotic use was collected over the first year of pregnancy. This period covered two stages: from preconception to pregnancy awareness and from pregnancy awareness to study enrollment. Participants were then divided into three groups: those who did not use antibiotics, those who used antibiotics during one of the two periods, and those who used antibiotics during both periods.
The researchers assessed participants’ psychological distress using the Japanese version of the Kessler Psychological Distress Scale (K6), a six-item self-report questionnaire in which participants answer six questions about their mental state.
The researchers then estimated the association between antibiotic use and psychological distress in the other two groups, using the group that did not take antibiotics as a reference group. They calculated adjusted odds ratios. This is a statistical measure used to estimate the strength of the association between two variables, in this case antibiotic use and psychological distress.
“We found that antibiotic use before and during pregnancy was associated with psychological distress in early to mid-pregnancy, and that this association showed a graded pattern in a national dataset of approximately 94,000 participants.” Professor Matsumura says:
After accounting for potential factors that may influence both antibiotic use and psychological distress, such as maternal age, prepregnancy body mass index, education level, income, smoking status, alcohol intake, marital status, and psychiatric history, the analysis found that compared with no antibiotic use, the adjusted odds ratio for moderate psychological distress (K6 score 5 to 12) was 1.12 for use in either time period and 1.12 for use in both time periods. 1.22. For severe psychological distress (K6 score >13), the adjusted odds ratios were 1.07 and 1.50, respectively.
Higher odds ratios were observed with greater antibiotic exposure, suggesting that the likelihood of psychological distress during early to mid-pregnancy was higher among participants who reported antibiotic use over a longer period of time.
One possible explanation for these findings involves the gut microbiota, which can be altered by antibiotics. Alterations in the gut microbiota have been observed in a variety of conditions such as obesity, diabetes, and inflammation, and such changes have also been examined in the context of psychiatric disorders.
The researchers stress that these findings do not suggest avoiding antibiotics when medically necessary. Rather, the results of this study may contribute to the ongoing debate on the appropriate use of antibiotics and efforts to reduce unnecessary prescribing.
“This study may make women planning a pregnancy or in the first trimester more aware of the appropriate use of antibiotics. Antibiotics are essential when medically necessary, but raising awareness about avoiding unnecessary prescriptions, such as for colds, may also make sense from a maternal mental health perspective.” Professor Matsumura concluded as follows.
sauce:
Reference magazines:
Matsumura, K., and others. (2026). Preconception antibiotic use and early to mid-pregnancy psychological distress in a national birth cohort: A cross-sectional analysis from the Japanese Environment and Children Study. BMC Public Health. DOI: 10.1186/s12889-025-26119-0. https://link.springer.com/article/10.1186/s12889-025-26119-0
