Parents in Wakefield are facing increasingly "limited" childcare options, because of falling numbers of daytime carers.
Three day nurseries have closed and 38 childminders have resigned since January 2018, leaving mums and dads in some areas struggling to find someone to look after their youngsters, according to a new Wakefield Council report.
All parents of children aged between three and four are entitled to 15 hours of free childcare a week, while some are allowed up to 30 hours.
But a report prepared for Wakefield's schools forum says that take-up of the 30-hour entitlement is lower in the more deprived parts of the district - a situation it warns has been made worse by the falling number of places available.
The inequality has extended to children's performance in schools, with pupils whose parents had taken up the 30 hours doing better than their peers.
The report said: "The childminding sector is of particular concern as childminders offer the greatest flexibility to parents.
"In some areas of the district, parents have limited choice if they want to take the full 30 hours in one place. This is further exasperated by falling childminder numbers.
"The data clearly shows that the children accessing the extended entitlement are living in the most affluent areas of the district, which raises the concern that the outcomes gap will widen in the future.
"Schools are stating anecdotally that those children attending up to 30 hours are already "flying" compared to their peers who only attend up to 15 hours."
Since the 15 hours entitlement was introduced in 2015, take up in the Wakefield district has been higher than the national average.
However, Castleford, Hemsworth, Knottingley and Normanton are among parts of the district where parents are less likely to use the scheme.
The report said that "gaps" in the number of places available were likely to be responsible for lower take up in these areas.
Local Democracy Reporting Service