Health experts have warned women who continue to smoke throughout pregnancy, saying the health of their unborn babies is at risk.
The British Medical Association (BMA) Scotland has said that while the number of women smoking in pregnancy has declined since the 1990s, a fifth of mothers-to-be continue their habit, despite growing evidence of the harm this can cause.
The organization is urging parents to mark World No Tobacco Day by giving up smoking for the sake of their family's health.
The BMA warned not enough was being done to warn parents about the consequences of smoking for their unborn child.
The dangers include an increased risk or premature birth, stillbirth and cot death.
Research shows that, with each cigarette a pregnant woman smokes, the blood flow through the placenta is reduced for about 15 minutes, causing the baby's heart rate to increase.
"Around one in five women smokes during pregnancy and, although this is an improvement on previous years, it reflects the lack of knowledge among Scots about the health risks of smoking, not only to themselves, but to the health of their children," the Scotsman quoted Dr Sally Winning, deputy chairman of BMA Scotland, as saying.
Winning said it was essential that the Scottish Government tackled the issue of parental smoking.
"Parents should be educated about the effects of smoking, not just on their own health, but to their children," Winning said.