One in six women who have large tissue removal during colposcopy will have a premature birth

Women who undergo a colposcopy but only have a small amount of tissue removed (less than 10mm depth) are not at increased risk of having a premature birth.  

The research, published in the BMJ, looked at women who gave birth following a colposcopy. 768 premature births and 830 full-term births were analysed, with scientists looking at the depth of tissue removed during treatment, before they gave birth.

Previously, it was unclear whether increased tissue removal during colposcopy definitely increased risk of premature birth, and there was also uncertainty on whether there is a safe depth of tissue removal, below which there is no increased risk.  

The study, funded by the National Institute for Health Research (NIHR), analysed more premature births in women with known depth of treatment than all previous studies combined. This is also the first study to determine similar risk of premature birth among women who had small amounts of tissue removed and those not treated at colposcopy.

Dr Alejandra Castanon, Epidemiologist and Lead Author of the study, Queen Mary University of London, comments: "There has been a lot of concern in recent years that treatment following cervical screening could be substantially increasing women's risk of having a premature birth.  This research has finally determined where the risk lies, and where it doesn't. The good news is most women will not be at higher risk of having a premature birth following their treatment.

"The majority of women attending colposcopy will either have just a diagnostic sample taken or will have only a small amount of tissue removed and these women have no additional risk of having a premature birth. Women who have more tissue removed and go on to become pregnant will require close monitoring to ensure the safety of both mother and baby."

Researchers are calling for the Colposcopy Treatment Guidelines, issued by the NHS Cervical screening programme, to be updated following these results. Clinicians should also be made aware that women who undergo tissue removal which is not particularly deep but where a large volume is removed are also at increased risk of a premature birth.