Asda, Tesco and Sainsbury’s follow Iceland in cutting the cost of formula after the manufacturer cut prices to retailers.
Asda and Tesco have joined Iceland in cutting the cost of Aptamil baby formula.
It comes after manufacturer Danone cut the price it charges retailers for the majority of its baby milk range by 7%.
Asda said from Monday its customers would also be able to pay for formula using rewards scheme vouchers for the first time.
The Competition and Markets Authority (CMA) said prices for baby formula milk had risen by a quarter in two years.
The regulator found competition was hampered because shoppers were reluctant to switch brands, either because they were recommended by friends and family or because their baby would only drink one.
There are rules banning retailers from advertising discounts on infant formula – for babies up to six months – because it might discourage breastfeeding.
In August Iceland called on the government to “immediately” update existing legislation so that retailers were allowed to tell the public when they reduce the price of formula.
The supermarket said at the time it still endorsed breastfeeding, yet rising costs were “placing unbearable pressure on parents who choose to or have no alternative” to using formula milk.
Iceland was the first supermarket to announce a price reduction, saying Danone’s cuts would be reflected in its stores. Asda said it would continue to work with its manufacturing partners to make sure price reductions were passed on to customers.
Kris Comerford, Asda’s chief commercial officer, said the supermarket understood that baby formula was a “vital necessity” for many.
He said: “Whilst we respect the regulations in place regarding the sale of baby formula, we want to do everything we can to help families manage their budget and keep their family fed.”
In November, the CMA found just two suppliers accounted for 85% of infant formula sales and there was “very limited availability” of cheaper own-brand alternatives.
New parents could make significant savings of £500 in the first year of a baby’s life on formula milk products by shopping around, the CMA added.
Danone told the BBC it would “continue to engage” with the CMA investigation.
The rise in costs has correlated with a spike in formula thefts as part of a surge of shoplifting during the cost of living crisis.