Link found between smoking and ectopic pregnancies

Scientists at the University of Edinburgh have identified a link between smoking and an increase in ectopic pregnancies.

Females who smoke regularly have higher levels of the protein PROKR1 in their Fallopian tubes, which increased the risk of an ectopic pregnancy, according to the research.

The study, funded by Wellbeing of Women, analysed the tissue samples of both female and non female smokers who had previously had ectopic and healthy pregnancies. The team at the University of Edinburgh believe that the chemical continine found in cigarette smoke initiates a series of reactions that consequently raises the levels of PROKR1 in the Fallopian tubes.

The team’s research demonstrates that cigarette smoke not only has adverse effects on the pulmonary tract but that components of the smoke can also enter into the blood stream and affects other, seemingly unconnected systems.

The PROKR1 protein normally allows pregnancies to implant correctly in the womb. If found in the fallopian tubes, it is believed to hinder the contraction of the tube walls and as a result the egg is unable to progress to the womb and is unable to develop.

The study showed that twice the levels of the protein were found in the Fallopian tubes of women smokers who had developed ectopic pregnancies. The study suggests that smoking increases the risk of ectopic pregnancy by up to four times.

Ectopic pregnancies are thought to effect between one and two per cent of all pregnancies in Europe and the USA, with 300,000 diagnosed in the UK alone every year.

Dr Andrew Horne, of the University’s centre for reproductive biology, told The Journal that he hopes “by proposing a potential mechanism for the link between smoking and ectopic pregnancy we have highlighted to the public that smoking is a considerable risk factor for the condition. I hope that this will make people think again about smoking when they are trying to get pregnant and that this in turn will have some effect on reducing the number of ectopic pregnancies in the UK.”