The new study on rats found that babies had a higher chance of being fat if their mother ate trans fats in pregnancy or while lactating.
Eating foods rich in trans fats while pregnant or breastfeeding could lead to fatter babies, new research has suggested.
Trans fats - which are contained in some biscuits, cakes, pies and crackers - have been linked to heart disease.
The experts behind the research called for further studies and warned of the implications for pregnant women.
The process of making hydrogenated fats and oils, which help extend the shelf life of products, can lead to the creation of trans fats.
Many takeaways and a wide range of snack foods contain these fats.
The study, by researchers at Sao Paulo Federal University in Brazil, was published in the journal Lipids in Health and Disease.
Luciana Pisani, who led the study, said: "We know that foetal growth is influenced by the mother's nutritional status.
"The nutritional conditions during pregnancy has a major role in the metabolic and hormonal interactions between the mother's body, placenta and foetus. We found that the fatty content of the babies' bodies increased when the mothers were fed the hydrogenated fat rich diet.
"We need to investigate this further as this has important implications for people's own diets, especially pregnant women."