With the adoption of routine PAP smear screening for dysplasia of the cervix, there has been a dramatic decrease in the incidence and mortality of cervical cancer. Concern exists, however, with the increased morbidity associated with treatments of cervical intraepithelial neoplasia and micro invasive cancer of the cervix, particularly as they relate to increases in preterm labour, preterm premature rupture of the membranes (PPROM) and second trimester pregnancy loss.

Mechanisms by which cervical procedures may cause adverse pregnancy outcomes include an attenuation of mechanical supports relative to the length of the cervix. Alternatively, a possible decrease in mucus production by the cervix may cause a subsequent increase in susceptibility to infection because of the loss of the mucous plug barrier.

Known risk factors for preterm labour include: advancing maternal age, maternal smoking, low socioeconomic status, advancing parity and previous preterm delivery.

The objective of this study is to determine the risk of adverse obstetrical outcomes associated with treatment – namely loop electrosurgical excision procedure (LEEP) and cone biopsy of the cervix - for high grade intraepithelial lesion, carcinoma in situ and micro invasive cancer of the cervix. In addition, we will analyze the risk associated with single and multiple treatments with LEEP and/or cone biopsy.

Adverse pregnancy outcomes to be studied include preterm labour (>37wks,>34wks,>28wks), PPROM and second trimester pregnancy loss. Our analysis will also look at the correlation between cervical cerclage placement for cervical incompetence and the relationship with previous cone biopsy(s)/LEEP procedures. In addition, we will investigate medical assessments (obstetrical triage visits) for threatened preterm labour. Our goal is to perform a multivariable analysis, controlling for known risk factors and confounders in the process.