International scientists conducting the new study looked at data on more than 2.5 million births and almost 250,000 hospital visits for asthma attacks.
Dr Jasper Been, from the University of Edinburgh, said:
Our research shows that smoking bans are an effective way to protect the health of our children.
These findings should help to accelerate the introduction of anti-smoking legislation in areas not currently protected.
Professor Aziz Sheikh, co-director of the university's Centre for Population Health Sciences, said:
This research has demonstrated the very considerable potential that smoke-free legislation offers to reduce pre-term births and childhood asthma attacks.
The many countries that are yet to enforce smoke-free legislation should in the light of these findings reconsider their positions on this important health policy question.
The findings are reported in the latest edition of The Lancet medical journal.
Smoking bans help to reduce premature births and childhood asthma, new research suggests.
A study of data from North America and Europe linked the prohibition of smoking in public places to a 10% fall in premature birth rates.
Hospital attendances for childhood asthma also dropped by the same amount in districts where smoking bans had been introduced.
Anti-smoking laws currently affect less than a sixth of the global population and 40% of children around the world are regularly exposed to second hand smoke, according to the study authors.
More research is needed into the link between smoking and the development of breast cancer in women over 50, US scientists said.
The call comes as a new study from the US National Cancer Institute in Bethesda, Maryland, found that women who smoked after menopause were 19% more likely to develop cancer.
DR Sarah Nyante said her study adds to the growing body of evidence of the association between smoking and increased breast cancer risk.
Previous studies have investigated this relationship, but questions remained regarding the extent to which other breast cancer risk factors, such as alcohol intake, might influence the results.
More work is now needed to understand the mechanisms behind the link between smoking and breast cancer in post-menopausal women.
Scientists in the US have established a new link between increased risk of breast cancer in older women and exposure to tobacco smoke.
The results held true even after accounting for increased alcohol consumption levels, which has already been established as a risk factor.
Former smokers were found to have a 7% higher chance of developing the deadly disease than those who had never smoked.
- US scientists who tracked the progress of 186,000 women aged between 50 and 71 found that those who smoked were 19% more to develop breast cancer than those who had not ever smoked
- Women who previously smoked but had managed to give up were 7% more at risk
A study in the US has found that smoking increases the risk of breast cancer in older women by almost 20%.
The study adds to a growing weight of evidence linking exposure to tobacco smoke and deadly disease.
A representative from a smokers' group has said the law should not be used to "stigmatise smokers as potentially unfit parents" after MPs approved plans to ban smoking in cars carrying children.
Simon Clark, director of the smokers' group Forest, said he was "disappointed but not surprised" by the result and warned that the Government will ban smoking in the home next:
Legislation will have very little impact because so few adults still smoke in cars carrying children. Those that do will carry on because it will be very difficult to enforce.
The overwhelming majority of adult smokers know how to behave towards children and the law should reflect that.
It shouldn't be used to stigmatise them as potentially unfit parents who can't be trusted to do the right thing without state intervention.
If you believed everything you heard in the House about the threat to children's health it's a miracle anyone who was a child in the fifties and sixties, when a large majority of adults smoked, is still alive.
Government has banned smoking in public places. Now they're going to ban it in a private place. The home will be next.
Shadow public health minister Luciana Berger has welcomed the result of a vote to ban smoking in cars with children as a "great victory for child health", but warned ministers not to "kick this into into the long grass".
"This is a great victory for child health which will benefit hundreds of thousands of young people across our country. It is a matter of child protection, not adult choice," the MP said.
"A time-limited consultation may be necessary on the practical details of implementation, but we will be watching closely to ensure the Government don't try and kick this into the long grass."
Some MPs have questioned how the plans will be enforced with some criticising the plans as a "nanny state" ban.
MPs have raised questions as to how the ban on smoking in cars carrying children will be enforced, with some criticising the plans as a "nanny state" ban.
The Health Secretary will be given the power to impose a ban despite the opposition.
Smoking in cars is wrong, but a statutory ban? Who'll enforce it? Do we ban kids standing by fires next! I'm voting against it.
I voted No to the Ban. I totally support the principle but think it will be unenforceable. Education needed.
After much deliberation, I voted against nanny state ban on smoking in cars, I was in a minority, legislation is going to be interesting
Medical charities have said they are "delighted" that MPs voted to approve plans to ban smoking in cars carrying children.
The British Lung Foundation estimate that more than 430,000 children aged between 11 and 15 are exposed to second-hand smoke in cars every week.
"Having campaigned on this issue for many years, we're absolutely delighted that MPs have backed the ban on smoking in cars carrying children," Dr Penny Woods, the charity's chief executive said.
"This could prove a great leap forward for the health of our nation's children.The introduction of a law that would help prevent hundreds of thousands of children from being exposed to second-hand smoke in the car is now within reach.
MPs have hailed plans to ban smoking in cars carrying children after it was overwhelmingly voted through in the Commons.
Despite opposition from some Conservative MPs, including Cabinet members, MPs approved the ban by 376 votes to 107.
Massive victory on banning smoking in cars with children! Brilliant news for children's health!
376-107 to ban smoking in cars with children present....majority 169. Hurrah. Thanks it will make a difference to 500000 children.