Cervical disease treatment is not associated with preterm birth risk

Cervical disease treatment is not associated with preterm birth risk

A study published online in theBritish Medical Journal reveals that treatment for cervical disease does not seem to raise the risk of premature deliveries after treatment. The study is the largest in the UK assessing the risks and the findings are contradictory to earlier studies, which indicated that treatment would increase the risk of premature deliveries.

Leading researcher Professor Peter Sasieni, professor of cancer epidemiology and biostatistics at London University's Wolfson Institute of Preventive Medicine, said:

"This finding is significant because approximately 40,000 women (most of whom are of child-bearing age) receive such treatment each year, and scientific literature had previously suggested that if any of these women became pregnant they would have an extra risk of about one in 18 (5.6%) of having a preterm birth. Considering all those treated previously who may be planning to have children, there may be half a million women in the UK who can relax now and not worry that they are at increased risk of a preterm birth."

In the UK, women aged between 25 and 64 years are invited for a cervical screening every 3 to 5 years in order to detect abnormal changes in the cervix that could be precursors of cervical cancer. Women who screen positive are invited back for further investigations, which could involve a colposcopy that magnifies the view of the cervix and a biopsy that involves taking a small tissue sample. The treatment for moderate or severe changes (cervical intraepithelial neoplasia (CIN) 2, or 3) is to remove the abnormal area of tissue, which can be done in various methods, but the most widely used in the UK is large loop excision of the transformation zone (LLETZ), whereby a small tool and electric current are used to cut out the affected cervical tissue.

Earlier research raised concerns that LLETZ and other treatment methods could raise the risk of premature deliveries, i.e. birth before the 37th week of gestation, yet according to these findings in the UK, there is no increased risk.

Professor Sasieni and his team from the Pre-term delivery after Cervical Treatment (PaCT) study group evaluated data from 44,210 UK women who underwent cervical biopsy and compared them with the hospital's obstetric records to identify 18,441 babies born to these women. The study did not include twins and triplets.

They assessed the percentage of preterm births, both before and after colposcopy and compared women who underwent LLETZ treatment with those who only had a diagnostic biopsy. Furthermore, they also compared preterm delivery rates with rates for the whole of the UK and discovered that compared with women of the general population with an average of 6.7% preterm births, those in the study had just over 2 extra premature births per 100 births (8.8% preterm). Of all study participants those who received treatment prior to their pregnancy had around 1.4 more additional premature deliveries per 100 than those who only had a biopsy before becoming pregnant.

Although they did observe a higher risk of preterm delivery in those women who delivered prior to having a colposcopy and those who went on to have treatment at colposcopy. Professor Sasieni commented: "Clearly treatment that has not occurred until after a birth cannot be causing preterm births."

After adjusting the results for variables, such as the type of treatment and whether it treatment was given prior or post birth, the team discovered no increased risk linked to treatment. They therefore concluded that the elevated risk of preterm deliveries in those treated for cervical disease was due to common factors that elevated the risk of both cervical disease and preterm delivery, but not to the treatment itself.

Sasieni explains:

"Women should have more confidence in going for cervical screening and accepting the treatment offered to them. Large loop excision of the transformation zone should still be seen as the treatment of choice. It would be premature to start using other treatments such as cryotherapy that may be less effective in treating cervical disease, in the hope that it would result in fewer preterm births."

In the UK, colposcopy and cervical intraepithelial neoplasia treatment is quality assured by the National Health Service cervical screening program and self-regulated by the British Society for Colposcopy and Cervical Pathology. All colposcopists have to be members and every 3 years colposcopy clinics in the UK are audited, which means that the colposcopy standard in the UK is likely to be higher and varies less compared with some other countries.

According to the team, this could partially explain the different results from other studies that were not conducted in the UK. They say: "There are still issues as to why many studies find a high risk of preterm birth associated with LLETZ, but this study shows that overall, LLETZ, as carried out in England, is safe. The difference may be due to the quality assurance of colposcopy in England. Other countries should consider, whether they need to tighten the regulation of colposcopy to ensure that treatment does not cause preterm births. Meanwhile, further research is needed to identify what caused the extra risk in other studies and whether or not extensive treatment and repeated treatment are also safe or whether they increase the risk of preterm delivery."

Professor Julietta Patnick CBE, Director of the NHS Cancer Screening Programs, concludes:

"We welcome these positive findings about the safety of treatment procedures for cervical disease in England. They are an encouraging reflection of the high standards of our NHS practitioners and our robust system of quality assurance. However, previous studies have shown that treatments, including colposcopy and LLETZ, are linked to an increased risk of pre-term deliveries, and it is important that we continue this project to provide firm evidence in this important area. Regular attendance at screening remains the top preventative measure against cervical cancer and we would encourage all women to make the decision to attend when invited."

Treatment for precancerous cervical disease and the risk of preterm birth (Video Medical And Professional 2020).

Section Issues On Medicine: Women health