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University of Iowa News Release

May 5, 2004

Study Links Cervical Dysplasia Treatments To Pregnancy Risks

Two treatments for removing precancerous tissue from the cervix are associated with an increased risk of preterm delivery (delivery before 37 weeks gestation) caused by the pregnancy complication known as preterm premature rupture of membranes (PPROM), commonly referred to as waters breaking too early, according to a new study co-authored by University of Iowa researchers.

The study, which urges physicians to carefully follow consensus guidelines for treatment of women with cervical abnormalities, appears in the May 5 issue of the Journal of the American Medical Association.

The objective of the study was to determine whether specific treatments for removing abnormal or precancerous cervical cells increase risk of preterm delivery in subsequent pregnancies. Cervical dysplasia is a precancerous condition that, if left untreated, can progress to invasive cervical cancer.

"Cervical cancer is the second most common cancer in women worldwide and the leading cause of cancer death among women in developing countries. But with regular Pap smear screening, it can be detected in its early or precancerous stages and effectively treated," said Audrey Saftlas (left), Ph.D., UI associate professor of epidemiology and a co-author of the study. "There are very few preventable cancers, and cervical cancer is one of them."

The investigators conducted a retrospective cohort study of pregnancy outcomes among 1,078 women evaluated at a New Zealand women's hospital between 1988 and 2000. Of that group, 426 women were not treated for cervical dysplasia, and 652 had at least one cervical treatment by laser ablation, laser conization or loop electrosurgical excision procedure (LEEP). Researchers then compared subsequent birth outcomes among the treated and untreated groups.

LEEP and laser conization are similar procedures that remove a cone-shaped wedge of tissue from the cervix. Laser ablation is used to vaporize smaller amounts of abnormal tissue from the surface of the cervix. The researchers noted that laser conization is rarely performed in current practice because it is more expensive and more technically difficult than LEEP.

"We found that women who had abnormal cervical tissue removed by LEEP or laser cone were two to three times more likely to have a preterm baby caused by their water breaking early. There was no increased risk associated with laser ablation," Saftlas said.

The researchers also found risk of preterm delivery caused by PPROM, and total preterm delivery increased significantly with the amount of tissue removed from the cervix.

Based on these findings, the researchers strongly recommended that health care providers adhere to the consensus guidelines for the management of women with abnormal Pap tests issued by the American Society for Colposcopy and Cervical Pathology (ASCCP) in 2001.

"We want to emphasize that these surgical procedures save lives and encourage women to be screened and treated as indicated for biopsy-proven cervical disease," Saftlas added. "Women with high-grade abnormalities should always be treated to prevent cervical cancer. However, physicians should give careful consideration to treatment of young women with low-grade disease because most of these cases will regress back to normal without therapy. Most women with low-grade disease should be closely observed without treatment, unless their condition progresses. This management strategy will likely reduce the risk of subsequent preterm delivery."

Additional authors of the report include Lynn Sadler, Melissa Exeter and Lesley McCowan, M.D., in Department of Obstetrics and Gynaecology at the University of Auckland, New Zealand; Wenquan Wang in Department of Biostatistics at the UI; and John Whittaker of the National Women's Hospital in Auckland, New Zealand. The study was funded by a grant from the National Institute of Child Health and Human Development of the National Institutes of Health.

STORY SOURCE: University of Iowa College of Public Health Office of Communications, 4257 Westlawn, Iowa City, Iowa 52242.

CONTACT(S): Media: Debra Venzke, 319-335-9647, debra-venzke@uiowa.edu