Artificially sweetened drinks in pregnancy linked to higher risk of overweight in offspring, Danish study finds

A large Danish cohort study published in the British Journal of Nutrition has found a significant association between maternal consumption of artificially sweetened beverages (ASBs) during pregnancy and an increased risk of overweight in their children from mid-childhood through to adolescence. The findings raise new questions about the long-term effects of artificial sweeteners during pregnancy, especially among women seeking alternatives to sugar to manage gestational weight.

Background

Childhood obesity has more than doubled over the past three decades, with excess weight in early life known to heighten the risk of type 2 diabetes, cardiovascular disease, and other long-term health conditions. Many pregnant individuals opt for diet drinks containing artificial sweeteners to avoid excess calorie intake and potential weight gain. These beverages are commonly perceived as a healthier substitute for sugar-sweetened alternatives.

However, emerging evidence suggests that artificial sweeteners may have unintended metabolic consequences, including disruption of gut microbiota, altered insulin responses, and increased cravings for sweet foods—even before birth. Although previous studies have reported conflicting results, some have linked prenatal exposure to ASBs with a higher likelihood of obesity in offspring. Given the widespread consumption of artificially sweetened products during pregnancy, further research into their long-term health implications is essential.

Study Design and Methodology

The present study is based on data from the Danish National Birth Cohort (DNBC), a nationwide longitudinal study that enrolled 101,042 pregnant women between 1996 and 2002. Participants were followed throughout pregnancy and their children tracked up to the age of 18.

Researchers collected detailed dietary and lifestyle information through telephone interviews at gestational weeks 12 and 30, and again at 6 and 18 months postpartum. A comprehensive food frequency questionnaire was administered at week 25 of pregnancy, capturing the frequency of ASB and sugar-sweetened beverage (SSB) intake. Consumption was categorised into four levels: none, less than one 250ml serving per week, 1–6 servings per week, and one or more servings per day.

The primary outcomes of interest were large-for-gestational-age (LGA) birth weight and overweight status of offspring at multiple time points: 5 and 12 months, and ages 7, 11, 14, and 18 years. Height and weight data were obtained from a combination of healthcare providers, parental reports, and self-reports by adolescents. Overweight status was defined using sex- and age-specific body mass index (BMI) cut-offs derived from standard deviation scores.

Women with pre-existing diabetes or incomplete data were excluded. Researchers adjusted for a wide range of confounding variables, including maternal age, pre-pregnancy BMI, smoking, physical activity, socioeconomic status, dietary quality (including SSB intake via the Healthy Eating Index), paternal BMI, and breastfeeding duration. Analyses were conducted using multiple logistic and linear regression models in R software.

Key Findings

Of the full cohort, 66,668 individuals provided valid data on ASB consumption, and 66,568 on SSB intake. Researchers found that women who consumed one or more servings of ASB per day were generally younger, had a higher pre-pregnancy BMI, were more likely to smoke, and had lower socioeconomic status. In contrast, those consuming fewer than one ASB per week tended to be more physically active and breastfed their infants for longer durations.

Early Life Outcomes
In infancy (at birth, 5 months, and 12 months), no association was found between maternal ASB consumption and increased risk of LGA or overweight in children.

Later Childhood and Adolescence
However, a consistent association emerged from age 7 onwards. Children whose mothers consumed either 1–6 ASBs per week or one or more per day during pregnancy had significantly higher odds of being overweight at ages 7, 11, 14, and 18 years, compared with children of mothers who reported no ASB consumption.

After adjusting for relevant confounding factors, daily ASB consumption remained significantly associated with higher overweight risk in offspring. At 18 years of age, the adjusted odds ratio (OR) for being overweight in the group exposed to ≥1 ASB per day was 1.26 (95% confidence interval [CI]: 1.12–1.42) compared to the non-exposed group. This pattern supports a potential dose-response relationship, where higher ASB intake correlates with greater risk.

SSBs and Unexpected Findings
Surprisingly, maternal consumption of SSBs was linked to a lower risk of overweight in offspring at ages 11 and 18. For example, children of mothers who consumed one or more SSBs daily had an adjusted OR of 0.72 (95% CI: 0.60–0.86) for overweight at 18 years, compared to those whose mothers did not consume SSBs. These findings were echoed in BMI z-scores: offspring exposed to ≥1 ASB per day had higher scores, while those exposed to ≥1 SSB per day had lower scores.

Researchers cautioned, however, that these inverse associations with SSBs could be influenced by unmeasured differences in socioeconomic or lifestyle factors. Mothers consuming SSBs tended to have lower pre-pregnancy BMIs and higher socioeconomic status, which may have contributed to the unexpected results, although adjustments were made for these variables.

Additional Analyses

Subgroup analyses, which used total energy intake as an adjustment factor rather than the Healthy Eating Index, yielded only minor differences in ASB-related outcomes, suggesting that the observed associations were not solely attributable to higher overall calorie intake.

Further modelling, in which ASBs were theoretically substituted with SSBs, indicated a reduced risk of overweight, reinforcing the hypothesis that artificial sweeteners themselves may play a role in long-term weight outcomes for children.

Of particular note is the timing of the observed effects: associations with overweight status only emerged from age 7 onwards. There was no elevated risk detected in infancy, which the authors suggest may reflect the onset of independent eating behaviours and the influence of early taste preferences shaped in utero. “These findings support the hypothesis that prenatal exposure to artificial sweeteners may alter long-term metabolic or taste-related pathways,” the authors noted.

Nevertheless, the study was unable to fully exclude the possibility of residual confounding by factors not captured in the dataset, such as the child’s postnatal diet or physical activity levels. Moreover, a significant data gap between 12 months and 7 years limits understanding of when weight differences may first begin to emerge.

The researchers also raised the possibility that individuals consuming ASBs during pregnancy might continue their use postpartum, potentially passing on artificial sweeteners through breastmilk. However, this remains speculative and was not directly examined in the study.

Implications and Conclusions

This large-scale cohort study adds to a growing body of evidence suggesting that consumption of artificially sweetened drinks during pregnancy may have unintended long-term consequences for the offspring. While the absolute increase in overweight risk is modest, the association persisted consistently across multiple age points and appeared to follow a dose-dependent pattern.

In contrast, the observed lower risk of overweight associated with SSB consumption should be interpreted cautiously. The authors emphasised that this may not reflect a protective effect of sugary drinks, but rather underlying lifestyle or demographic differences.

“These results challenge the current dietary recommendations for pregnant individuals—particularly those with overweight or diabetes—who are often encouraged to substitute sugar with artificial sweeteners,” the authors wrote.

Although more research is needed to clarify mechanisms and account for limitations such as the postnatal diet and the mid-childhood data gap, the study calls for a re-examination of nutritional advice during pregnancy. It also highlights the need for further investigation into safer and more effective alternatives for managing gestational weight.

Given the rising prevalence of childhood obesity, even small shifts in population-level risk carry important public health implications.