Mothers-to-be should avoid eating snacks that have been doused in vegetable oil, experts have once again warned.

Scientists fear linoleic acid, an omega-6 fat, could harm babies in the womb after they discovered it causes internal swelling in tests on rats.

They warned consuming too much of it may lead to 'pregnancy complications and poor development of babies'.

Vegetable oil, often used to cook pizzas, potato-based snacks and bread, is one of the biggest sources of linoleic acid.

NHS guidance states mothers-to-be should have only small amounts of foods rich in unsaturated fat, such as vegetable oils. 

Vegetable oil, often used for cooking pizzas, potato-based snacks and bread, is one of the biggest sources of linoleic acid

It also urges them to steer clear of fatty foods such as pizza and chips - but not because they contain linoleic acid. 

Researchers based at Griffith University, Brisbane, gave rats a diet high in linoleic acid for 10 weeks.

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