Introduction

Cervical intraepithelial neoplasia (CIN) has a high incidence in the reproductive age groups. The peak incidence of CIN grade III in the UK is at around the age of 30 years, which means that clinicians in colposcopy clinics frequently encounter women with CIN who are pregnant. These cases require considerable experience by the colposcopist and modification of certain principles that apply to the nonpregnant situation.

Cervical smears in pregnancy

The current NHS cervical screening programme (NHSCSP) guidelines recommmend that if a pregnant woman has a regular and negative screening history, cervical smears should be deferred until postpartum. It has been suggested that cervical smears should not be routinely taken in pregnancy because of difficulty in their interpretation — this is due to pregnancy-related inflammatory or reactive changes, which may be revealed on cytology of a cervical smear taken in pregnancy. In addition, cervical sampling in pregnancy can lead to minor vaginal bleeding that can cause anxiety to the pregnant woman. However, there is evidence to suggest that the rate of inadequate smears in the first trimester is low and that smear taking at that time is not associated with adverse pregnancy outcomes such as miscarriage or rupture of membranes. In keeping with this, the NHSCSP guidelines recommend that if the previous test has been abnormal and the woman has since become pregnant, the test should not be delayed.