Mums-to-be are to be subjected to breath tests to see if they are secretly smoking during pregnancy.
An NHS watchdog is demanding that midwives test pregnant women at their antenatal appointments.
The test is to weed out women who lie about not smoking while expecting, or who have claimed they have given up.
Those who are found to have carbon monoxide present in their breath will be referred to classes to help them with their nicotine addiction.
The new guidelines are from NICE - the National Institute for Health and Care Excellence - and are said to be launched in an attempt to reduce the number of pregnant women who continue to smoke.
Current figures suggest that 21 per cent of mums-to-be smoke during pregnancy, resulting in a heightened risk of health problems for their babies.
Midwives have hit out at the controversial new plans, claiming it will harm their relationship with their patients. A source told the Sunday Times that the new guidelines were 'ill-judged' and that midwives should not be 'policing pregnant women'.
The Sun reports that the test will not be compulsory, but says midwives fear many mums-to-be will feel under pressure to take it.
What do you think? Too much of a nanny state or a good idea?
More on Parentdish: I smoked during all my pregnancies