Study Highlights Effect of Caffeine Intake While Pregnant on Childhood Asthma

Maternal caffeine consumption during pregnancy is linked to a reduction in risk of childhood asthma up to approximately 93 mg per day, according to recent findings, though the risk of adverse effects linked to caffeine intake on some health outcomes suggests the need for additional research.1

The authors of this analysis were led by Francisca de Castro Mendes, from the EPIUnit-Institute of Public Health at the University of Porto in Portugal. The investigators pointed to previous data such as the Danish National birth cohort findings which indicated that coffee intake while pregnant slightly diminished childhood asthma risk.2

Despite the presence of data on the subject, Mendes et al. highlighted the fact that there had been sparse information regarding longer-term influence of caffeine consumption.

“Therefore, using data from a Portuguese population-based prospective birth cohort study, we aimed to investigate the association between maternal caffeine intake during pregnancy with asthma and lung function in children by 10 years of age,” Mendes and colleagues wrote.1

Trial Design Details

The investigative team invited mothers and their newborn babies, between April 2005 - August 2006, to participate in this analysis. They accessed these individuals though public obstetric and neonatal care units located in the metropolitan area of Porto, Portugal and utilized data drawn from the Generation XXI (G21) population-based study.

Ultimately, the researchers ended up with 8495 mothers and 8647 babies in their research. The team conducted subsequent follow-up meetings at the point in which these children reached 4 years, 7 years, and 10 years of age, adding that rates of participation were 86%, 80%, and 76%, respectively.

The investigators recorded maternal levels of caffeine intake through interviews with subjects, looking at their consumption of black and green tea, regular and decaffeinated coffee, and cola beverages. Their interviews were carried out within 72 hours of the childrens’ delivery, with the research team determining total intake by calculating the amount of milligrams consumed per day.

The team based any asthma diagnoses on medical evaluations and spirometry with bronchodilation at the childrens’ tenth year. The investigators used adjusted regression models to look at the relationship between maternal caffeine consumption during pregnancy and childhood risk of developing asthma.

The analysis specifically accounted for confounding variables which included gestational age, pre-pregnancy caffeine consumption, maternal history with asthma, maternal level of education, smoking status, and the child’s reported sex.

Notable Findings

The researchers reported by their study’s conclusion that there was a nonlinear relationship identified between maternal consumption of caffeine and risk of developing asthma at age 10, with a quadratic coefficient (OR = 1.20, 95% CI: 1.04; 1.39). The team further noted that higher daily intake of caffeine while pregnant was shown to be linked with reduced odds of childhood asthma (adjusted OR = 0.60, 95% CI: 0.41; 0.88).

A knot point of 92.7 mg/day (95% CI: 36.3; 163.3) was highlighted by the investigators, with the asthma risk at this level estimated at 7.2%, compared to 8.8% for no caffeine intake.

The team’s data indicate that moderate maternal caffeine consumption while a parent is pregnant—up to approximately 93 mg/day—may result in a diminished likelihood of asthma in children by the age of 10. While these findings suggest a potential protective effect, additional research is necessary to validate these conclusions due to other concerns related to caffeine intake during pregnancy.

“Given the uncertainty regarding the adverse effects of caffeine intake on some health outcomes…prudence suggests limiting caffeine intake during pregnancy, and further studies are required to better understand the mechanisms behind the relationship of maternal caffeine intake during pregnancy and asthma development in children,” they concluded.1

References

1. de Castro Mendes F, Severo M, Paciência I, et al. Maternal caffeine intake during pregnancy and the risk of childhood asthma by 10 years of age—Evidence from The Generation XXI birth cohort study. Pediatr Allergy Immunol. 2025; 36:e70024. doi:10.1111/pai.70024.
2. Liu X, Liew Z, Olsen J, et al. Association of prenatal exposure to acetaminophen and coffee with childhood asthma. Pharmacoepidemiol Drug Saf. 2016; 25(2): 188-195.