Examining the Evidence
Q.Does cervical dysplasia raise the risk of preterm birth?
<huc>A.</huc>Yes—and the risk is elevated whether or not the cervical lesions are treated, although it is higher among treated women. As for the treatments themselves, cone biopsy, loop electrosurgical excision procedure (LEEP), and diathermy were all associated with preterm birth, while laser ablation was not.
Preterm birth and cervical dysplasia share many risk factors, most of which are the progeny of low socioeconomic status. It is not surprising, therefore, that cervical dysplasia is a risk factor for pre-term birth independent of the treatment modality chosen for the precancerous condition. This large cohort study linking outpatient gynecologic records with childbirths from Australia found exactly that. It is the largest study so far to focus on pregnancy outcomes in women following diagnosis and treatment of dysplasia. Frustrating to both the obstetrician and the gynecologist is the fact that smoking is the only readily modifiable risk factor for preterm birth or cervical dysplasia.
Ablative procedures produce better pregnancy outcomes than excision
Beyond epidemiology, this paper bears an important message for clinicians and patients: Procedures that remove portions of the cervix, such as LEEP, diathermy, and cone biopsy, raise the risk of subsequent preterm birth, compared with less destructive ablative procedures such as laser ablation (as reported in the Up-date on Cervical Disease, by Thomas C. Wright, MD, in the March issue of this journal). This was also demonstrated in a large review of the subject.1 Therefore, for an optimal obstetrical outcome, ablative procedures are preferable to excisional ones in women who have not yet completed childbearing. Given that success rates are only slightly lower for ablative procedures than for destructive ones, a clinician can recommend ablation without fear of dysplasia progressing to invasive cancer.
Widespread HPV vaccination could help reduce preterm birth rate
This study highlights how a systematic program of human papillomavirus (HPV) vaccination in adolescents (male and female) before their coital debut could reduce the rate of preterm birth by eliminating the need for women to undergo excisional treatment for cervical dysplasia. The possibility for such improvement in birth outcomes should motivate those of us working to prevent preterm birth to advocate for societal investment in this approach. It also might alleviate concerns that HPV vaccination has the potential to disrupt family life by encouraging promiscuity. How can anyone argue against a program that will prevent cancer and preterm birth?
1. Kyrgiou M, Koliopoulos G, Martin-Hirsch P, Arbyn M, Prendiville W, Paraskevaidis E. Obstetric outcomes after conservative treatment for intraepithelial or early invasive lesions: a systematic review and meta-analysis of the literature. Lancet. 2006;367:489-498.