Age at first pregnancy and the viral etiology of cervical neoplasia

In a retrospective study of cervical neoplasia, the relative risk estimate (with 95% confidence limits) of a first pregnancy before 22 years of age was 2.6 (1.41;5.12), with regard to the herpes simplex virus (HSV) infection 6 (2.05;23.81) and with regard to the cytomegalovirus (CMV) infection 2 (1.07;3.85). There was no relation between gravidity and cervical neoplasia. After eliminating the confounding effect of the HSV and the CMV infection, the relative risk for cervical neoplasia of a first pregnancy before 22 years of age was estimated to be 2.17 (1.24; 3.80). There was no evidence of a tumor-promoting role of low age at first pregnancy in the possible neoplastic outcome of the HSV and CMV infections. The association between low age at first pregnancy and cervical neoplasia presumably results from the association between a low age at first pregnancy and the occurrence of a causal infectious agent other than HSV and CMV.