European research is the first to prove that cigarettes reduce female fertility by making it more difficult for an embryo to implant.
Australian infertility specialist Michael Chapman says that while smoking was known to reduce pregnancy chances, experts had previously believed it was the egg - not the womb - that was most affected.
"This really does signal a change in direction," said Professor Chapman, from the clinic IVF Australia.
The study, published today in the journal Human Reproduction, compared the pregnancy rates of smokers who used donated eggs in IVF with those who smoked fewer than 10 cigarettes a day or none at all.
The scientists from Spain and Portugal investigated the first cycles of egg-donated IVF treatments at a Spanish clinic between 2002 and 2005.
There were 741 cycles among light or non-smokers and 44 in those who smoked more than 10 cigarettes day.
None of the prospective fathers were smokers, and none of the women who donated eggs smoked heavily.
"The non-heavy smokers had a significantly higher pregnancy rate, with over half becoming pregnant (52.2 percent), compared with just over a third (34.1 percent) of the heavy smokers," said lead researcher Dr Sergio Soares.
This proves a new finding - that cigarette smoking negatively affects the receptiveness of the uterus independently of its effect on ovarian function.
But once heavy smokers do get pregnant they were far more likely to have a multiple birth, with 60 percent expecting twins compared with 31 percent of light or non smokers.
Dr Soares said the study should change doctors' advice given to prospective mothers.
"It means that we should now be telling patients, if they are heavy smokers, that even if fertilisation takes place they have less chance of achieving a successful pregnancy, whether they are trying to conceive naturally or through IVF, and particularly with donated (eggs)," he said.
"We should also warn them of the risks of multiple births, as multiple births are less safe for mothers or babies."
Prof Chapman said the findings added further fuel to anti-smoking messages.
"It's totally consistent with what we've been preaching – that smoking impairs fertility - but it gives new reasoning," said Prof Chapman, who is head of women's and children's health at the University of NSW in Sydney.
"The message still remains that reduction is helpful but giving up is better."