Three studies offer insights into maternal conditions in pregnancy and ASD odds in children

Three recent studies have explored whether maternal medical conditions during pregnancy can affect the rate of autism spectrum disorders (ASD) in children.

The first study, by researchers in Japan, focused on endometriosis, a condition in which tissue similar to the inner lining of the uterus grows outside the uterus. Endometriosis affects 5% to 10% of women of reproductive age, and because it can cause inflammation—which is strongly linked to ASD—there has been speculation that endometriosis may increase the likelihood of a child having ASD. However, while several small studies investigated this issue, the findings were inconsistent.

To examine this question further, Maho Furukawa and colleagues analyzed data from health insurance records for 30,020 mother-child pairs. They calculated the rates of ASD in children of mothers with and without a diagnosis of endometriosis and report, “No significant association of maternal endometriosis with ASD in offspring was detected in this study.” They conclude, “These findings suggest children whose mothers have an antepartum history of endometriosis alone may not need to be closely monitored for ASD.”

In the second study, an international team led by Evora Hailin Zhu explored the association between maternal rheumatoid arthritis (RA) during pregnancy and autism spectrum disorders (ASD) in children. The study analyzed data from two Israeli birth cohorts comprising more than 560,000 children, dividing mothers into those diagnosed with RA before delivery and those diagnosed only afterward. In addition, the researchers conducted a meta-analysis of 13 previous studies exploring maternal RA and autism in offspring.

The researchers say that based on the data from the Israeli cohorts and their metaanalysis of other studies, “the current study indicates a modest but robust increase in the risk of ASD among offspring of mothers diagnosed with RA before delivery, but not when diagnosed only after delivery.” They note that if the association between maternal RA and ASD in offspring stemmed primarily from genetic factors, this association would not be influenced by timing. “This temporal specificity,” they say, “argues against shared genetic etiology and points toward maternal inflammatory status during pregnancy as a causal factor in offspring ASD risk.”

The third study, by an Israeli research team headed by Leena Elbedour, focused on hypothyroidism. The researchers analyzed electronic medical records for more than 51,000 births, identifying 4,409 mothers who had abnormal thyroid function during pregnancy. Of these, 1,161 had chronic hypothyroidism, 1,600 had gestational hypothyroidism, and 1,054 had both chronic and gestational hypothyroidism.

The researchers say that a diagnosis of chronic hypothyroidism alone, which most likely reflected adequate treatment, was not associated with ASD in children. However, they say, “[C]ombined chronic and gestational hypothyroidism was associated with higher ASD risk.” The longer the period of hypothyroidism lasted during pregnancy, the greater the odds were of a child receiving an ASD diagnosis.

The researchers say, “While causal conclusions are premature, these results are consistent with recommendations for routine monitoring of thyroid hormone levels and treatment of imbalanced thyroid function with thyroid hormone medications to maintain euthyroidism [normal thyroid function] in pregnancy.”

Citations

“Association of maternal endometriosis with autism spectrum disorder in offspring: a retrospective cohort study,” Maho Furukawa, Osamu Wada-Hiraike, Yuki Enomoto, Saki Tsuchimochi, Takayuki Iriyama, Yusuke Sasabuchi, Hideo Yasunaga, Yasushi Hirota, and Yutaka Osuga, BMC Pregnancy and Childbirth, December 2025 (online). Address: Osamu Wada-Hiraike, Department of Obstetrics and Gynecology, The University of Tokyo, Tokyo, Japan, [email protected].

—and—

“Maternal rheumatoid arthritis and the risk of offspring autism spectrum disorder: two national birth cohorts and a meta-analysis,” Evora Hailin Zhu, Benjamin HK Yip, Caroline Fyfe, Eugene Merzon, Arad Kodesh, Johan Askling, Abraham Reichenberg, Weiyao Yin, Stephen Z. Levine, and Sven Sandin, Molecular Autism, December 4, 2025 (free online). Address: Benjamin HK Yip, [email protected].

—and—

“Maternal thyroid hormone imbalance and risk of autism spectrum disorder,” Leena Elbedour, May Weinberg, Gal Meiri, Analya Michaelovski, and Idan Menashe, Journal of Clinical Endocrinology & Metabolism, November 25, 2025 (free online). Address: Idan Menashe, Department of Epidemiology, Biostatistics and Community Health Sciences, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva 8410501, Israel, [email protected].