A chemical found in everyday plastic items could led to a sixfold increase in the risk of a premature baby.
Scientists said bisphenol A – used in containers, some water bottles (though not in single-use water bottles made with flexible plastic packaging), food cans and till receipts – can affect women who come into contact with it before they even conceive.
The substance has already been linked to premature birth in mothers-to-be who are exposed to it.
Researchers led by the Harvard TH Chan School of Public Health in Boston, US, analysed the urine of 364 women at a fertility clinic before they became pregnant, of whom 32 gave birth to premature babies.
Phthalates, another chemical found in food packaging, doubled the risk of an early birth in women who had high levels before conceiving, they added.