According to Conservative MP, Douglas Carswell, women are being rewarded for "bad behaviour" in a scheme that offers mothers-to-be £100 to stop smoking.
The initiative by North-East Essex NHS Trust is a bid to tempt expectant mothers into stopping by offering shopping vouchers in return for their compliance, the trust said.
The deal sees pregnant women receive £20 after stopping for a week, a further £40 after a month of abstinence, and a final £40 if they give up for a whole year.
But Conservative MP for Harwich Douglas Carswell said: "There's not a mum or dad in the country who doesn't know smoking is very bad for unborn children. The question is, why are we committing to a scheme that provides pocket money for bad behaviour? People shouldn't be smoking in the first place."
Defending the move, the trust said that smoking during pregnancy can lead to complications during labour, as well as an increased risk of miscarriage, premature birth and stillbirth.
Sue White, co-ordinator of the trust's stop smoking service, said the shopping vouchers - for Co-op stores in the east of England - could make the difference between quitting and continuing smoking for many women.
"Ridiculous! Prevention is the key and more smoking cessation support for pregnant women. Don't start in the first place and better education regarding the disadvantages of smoking for young people." - Helen McGrath, Brighton