Parents in around a fifth of areas in England are finding it harder to get their child in to their top choice of primary school, figures suggest.
In the last 12 months, in a significant number of towns and cities, the proportion of families gaining their first preference, or one of their top three favoured primaries has fallen.
The statistics, based on an analysis of government data by the Press Association, come just days before the deadline for families across the country to apply for primary places for children due to start school this autumn.
There have been concerns about a squeeze on school places, fuelled in part by a rise in the birth rate in the early 2000s, which is now working its way through into secondary schools.
The Press Association analysis of Department for Education (DfE) data for the 2017/18 academic year, 28 out of 150 local councils (19%) saw a drop in the proportion of pupils offered their first preferences of primary school, compared with the year before.
A total of 121 (81%) saw an increase in the proportion of first-choice offers, while for the others there was no change compared with 2016/17.
In addition, 31 authorities (21%) have seen a drop in the proportion of first-choice offers made to pupils compared with three years ago (2014/15), with 113 seeing an increase (75%) and the rest no change.
Families typically list a number of choices, in order of preference, on school application forms.
The analysis also looked at the proportion of pupils who were offered one of their top three choices and found that last year 26 out of 150 councils (17%) saw a fall in the proportion of pupils who were given one of their top three preferences, compared with 2016/17.
A total of 118 authorities (79%) had seen a rise in top three offers over this 12-month period, while the others saw no change.
It also showed that 26 out of 149 authorities (17%) for which data was available had seen a fall in top three preferences compared with 2014/15, while 122 saw an increase (82%) and the rest no change.
Justine Roberts, founder and chief executive of parenting website Mumsnet, said: "Lots of parents believe getting into the right primary school will have a big impact on their children's life chances and happiness, and in some areas over-subscription to 'good' schools makes things pretty fraught.
"Most families get their first choice, which is cause for celebration - but it's not much comfort to those who are desperately disappointed.
"However, Mumsnet users who've been through the admissions mill - some of whom didn't get the school they wanted - tend to say, with hindsight, that whatever their Ofsted ranking, primary schools are almost always warm, supportive places where children thrive."