CIN and pregnancy
CIN is an abbreviation for cervical intraepithelial neoplasia. The cervix is the lower part of the uterus, the epithelium the superficial layer of cells of the cervix, and the neoplasia a neoplasm, i.e. abnormal cell growth. CIN is therefore a neoplasm of the superficial cells of the cervix and it is divided in 3 stages: CIN 1, 2 and 3, depending on the thickness of the epithelium the neoplasm is affecting. CIN 3 is when those changes affect more than 2/3 of the thickness of the epithelium which represents a pre-cancerous state of the cervix. The latency period from CIN 3 to cervical cancer is about ten years although shorter periods have been recorded. According to some data, every year around 60,000 women are affected by cervical cancer, of which 30,000 die in the European Union. In our country around 350 women are diagnosed with cervical cancer every year. CIN 3 usually occurs between the ages of 25 and 29, and cervical cancer between the ages of 40 and 50.
According to newer classifications, SIL abbreviation (Squamous Intraepithelial Lesion) has been introduced. Therefore, CIN 1 is positioned in the LSIL group (Low Squamous Intraepithelial Lesion), and CIN 2 and 3 in the HSIL group (High Squamous Intraepithelial Lesions).
The frequency of CIN in pregnancy is estimated at about 4-5% which is about the same as in the general population.
HPV (Human papillomavirus) is connected to the occurrence of CIN. It is the most common sexually transmitted disease and most people are no even aware that they are affected. According to research, around 80% of people who are sexually active already have or will be affected by HPV and 50-80% spontaneously heal so that it is not necessary to treat HPV infection, but only its consequences if they occurred. There are around 150 types of HPV, 40 of which cause infections of the genital region and there is high and low risk HPV. HPV infection, according to research, does not affect pregnancy and neither do CIN changes. There has not been found a connection between HPV and miscarriage, early birth or some other pregnancy-related complications.
Since CIN does not usually have any symptoms, the diagnosis is done with the Pap test. In early pregnancy, Pap test is one of the examinations that is routinely done. Unfortunately, pregnancy is still the only period of life for some women to do this test.
Pap test is a screening test with which CIN changes can be found. It is also called VCE (vagina-cervix-endocervix). The US scientist Papanicolaou took it to routine practice and made the first classification in 1954, after who the test got its name. This smear is easily taken on the gynecological table: after insertion of the speculum, the gynecologist takes a smear with the wooden spatula from the posterior arch of the vagina and the vaginal part of the cervix. After that, he takes a smear from the vaginal canal with a brush, and the cytologist examines and describes the changes in the laboratory. Pap test accuracy is 75-80%, and in combination with other methods such as colposcopy and biopsy, it can be as high as 95%.
Colposcopy is a painless examination of the cervix with the colposcope after putting various chemical agents on the cervix to better see the changes if there are any. Colposcopy in pregnancy has its unique characteristics. It is more difficult to perform, and experience is necessary because many examinations of this type are normal in pregnancy, although in women who are not pregnant might look very suspicious. We need to exclude cancer during pregnancy with this examination. Biopsy is avoided in pregnancy and is done exclusively if there is serious suspicion on invasive cervical cancer.
In CIN treatment, we use the safest approach, and especially in pregnancy. Spontaneous progression of CIN 1 changes, both during pregnancy and non-pregnancy period, is around 60%, CIN 2 and 3 around 35%. However, this must not reduce awareness about dangers of long term CIN persistence and women have to be responsible for their health and routinely come to control examinations to the gynecologist. In cases of CIN changes prior to pregnancy, it is advisable to treat the changes and then plan pregnancy. To summarize, according to most scientific literature, 33% of all CIN changes after birth persist, 64% of them go into regression and 3% into progression.
According to modern protocols, pregnant women with CIN are followed cytologically and only in suspicious cases with colposcopy every 6-8 weeks. If after giving birth and only on control Pap examinations those changes persist, we treat them following appropriate guidelines 8-12 weeks after giving birth.