Research by the insurer Aviva says that since September last year, 32,000 women have given up their jobs to stay at home and look after their families.
The figure is taken from the Labour Force survey by the ONS.
The survey of 6,000 families found that in some cases, particularly for women working part-time, a working mother could be financially worse off.
For a woman with a partner with two children, a one-year-old and a seven-year-old, working part-time could actually mean a loss of £98 a month, once childcare costs and related costs for work, such as commuting and food, are taken into account. Working full-time she would be £120 a month better off.
However, the same woman working part-time and not having to pay for childcare would have an income of £402 left at the end of the month.
For single parent families the situation is worse. A single parent relying on full-time childcare would be worse off by £225 a month after costs.
Families in the report typically spend on average £385 a month on childcare.
The Family Finances report says that for some families it does not appear to make financial sense for both partners to work if they are also paying substantial childcare costs.
Louise Colley, head of protection for Aviva, said, ‘This report shows very clearly the challenge many families with young children face as they balance their income with the cost of childcare. As care costs rise, it is quite possible we will see more and more couples relying on one salary while the other person looks after the children – simply because they may actually be worse off if both people work.’