TOPLINE

Children born to mothers with higher gestational weight gain or hypertensive disorders of pregnancy had an increased risk for juvenile idiopathic arthritis (JIA). Maternal prepregnancy BMI was not associated with an overall risk for JIA; however, genetic susceptibility appeared to modify the association between maternal BMI and the risk for JIA.

METHODOLOGY

• Researchers analysed data from a prospective Norwegian cohort (MoBa) to evaluate whether maternal and perinatal characteristics including prepregnancy BMI, gestational weight gain, hypertensive disorders of pregnancy, and birth weight were associated with the risk for JIA in offspring.
• They included 78,901 singleton children and captured JIA diagnoses between 2008 and 2023; 265 children (61% girls) had JIA.
• All children were at least 14 years old and 85% were at least 16 years old at follow-up.
• The researchers also assessed whether hypertension or birth weight mediated the association between gestational weight gain and JIA. Interactions between maternal exposures and a JIA polygenic risk score were evaluated in a genotyped subgroup of 44,245 children, including 192 with JIA.

TAKEAWAY

• Each 1-SD increase in gestational weight (approximately 6 kg) was associated with a modest increase in the risk for JIA, although the CI value was borderline (adjusted odds ratio [aOR], 1.12; 95% CI, 1.00-1.26). The association was stronger among women with prepregnancy obesity (aOR, 1.40; 95% CI, 1.10-1.77) and female children (aOR, 1.25; 95% CI, 1.08-1.45).
• Maternal hypertension and preeclampsia were independently associated with 43% and 61% higher adjusted odds of JIA, respectively.
• The association between gestational weight gain and JIA was not mediated by maternal hypertension or birth weight. Prepregnancy BMI and birth weight showed no clear association with the risk for JIA.
• Among children with a low genetic risk, maternal overweight was associated with a lower risk for JIA than normal maternal BMI (aOR, 0.37; 95% CI, 0.17-0.80).

IN PRACTICE

"From a public health perspective, our study supports the importance of optimising maternal health during pregnancy, but these findings warrant further investigations in independent cohorts before informing preventive strategies," the authors wrote.

SOURCE

The study was led by Vilde Øverlien Dåstøl, Oslo University Hospital, Oslo, Norway. It was published online on July 30, 2026, in RMD Open.

LIMITATIONS

The study lacked data on subtypes of JIA. The relatively small number of JIA cases may have limited statistical power. The predominantly Northern European study population may have limited the generalisability of the findings.

DISCLOSURES

The study received funding from multiple sources including Foundation DAM, the South-Eastern Norway Regional Health Authority, and Norwegian Rheumatism Association. One author disclosed serving as a consultant to Precision Health and receiving speaker honoraria from multiple pharmaceutical companies.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.