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Smoking while pregnant appears to put the future fertility of any female children at risk. Researchers believe this could be because tobacco smoke has a damaging effect on the developing fallopian tubes.
Women who smoke are known to be at an increased risk of tubal disease. Scientists believe this could be because tobacco smoke increases the risk of infections of the pelvis, and appears to have a damaging effect on the immune system.
However, a team from the University of Leeds has carried out research that suggests that female smokers may also be putting their unborn babies at a similar risk.
They believe that prenatal exposure may result in direct permanent damage to the developing oviducts of the unborn child.
The oviduct is the upper third of the fallopian tube where fertilisation of the egg most often takes place.
The researchers carried out an analysis of 239 women undergoing IVF, or an alternative form of fertility treatment called ICSI.
Other factors
They found that 68% of the smokers showed signs of tubal disease, compared to just 29% of the non-smokers.
The researchers admit other factors, such as age, social class, alcohol intake, a previous abortion, and a history of ectopic pregnancy were likely to play a considerable part in determining the risk to individual women.
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"It is also the first study to demonstate that prenatal exposure to tobacco smoke is associated with a significant increase in tubal disease in offspring" |
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Dr Sara Matthews, University of Leeds |
However, even after taking these factors into account, they found that women whose mothers smoked were much more likely to show signs of tubal disease than those whose mothers did not. The figures were 52.5% compared to 28.8%. Tubal disease was still more likely in those who experienced foetal tobacco exposure, even when only non-smoking patients were considered.
Researcher Dr Sara Matthews told the European Society of Human Reproduction and Embryology annual conference in Vienna: "This study demonstrates that smoking probably does cause tubal disease.
"It is also the first study to demonstate that prenatal exposure to tobacco smoke is associated with a significant increase in tubal disease in offspring.
"It is a subject that requires further investigation."
Dr Matthews said there were a number of potential reasons why smoking could cause problems.
It is known to depress the action of the immune system, increasing the risk of disease.
It also results in decreased flow of blood to the oviducts.
Ectopic risk
It is possible that tobacco smoke causes changes to the way the egg travels down the fallopian tubes, increasing the risk that it will not implant in the correct place.
Previous research has shown that smokers at increased risk of ectopic pregnancy - when a embryo starts to grow in the wrong part of the reproductive tract. It has also shown that the site of ectopic pregnancy is much more varied than in women who do not smoke.
Based on a smoking rate of 25% among females, it is estimated that 13% of infertility problems could be related to smoking.
Smokers also have a third higher chance of having a spontaneous abortion during the first three months of pregnancy.
Dr Chris Ford, of Bristol University, an expert on the effect of smoking on fertility told BBC News Online the results were interesting.
However, he said the researchers appeared not to have taken account of whether the women had a history of sexually transmitted diseases, which could be a significant influence on their ability to get pregnant.
He said: "Women undergoing IVF are a selected population who will be more likely to exhibit tubal disease than women drawn from the general public.
"The numbers probably overestimate the risk to the female foetus of smoking during pregnancy."
However, he added: "Having made these points the effect appears to be highly significant and deserves wider attention and will I am sure stimulate further research to confirm or to refute the conclusions."
[BBC News Online]
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Last Revised at December 10, 2007 by Lusine Kazoyan, M.D.
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