Background Most Japanese pregnant women undergo a first-trimester cervical cytological screening because of both the low rates of HPV vaccination and routine cytological screening. We aimed to investigate obstetric and oncologic outcomes of perinatally diagnosed invasive cervical cancer (ICC), and whether cytological screening during pregnancy was useful.

Methods We retrospectively reviewed the clinical data on ICC diagnosed during pregnancy or within one year after delivery from 2010 to 2019.

Results Of the 18 ICC patients, we diagnosed eight during pregnancy and ten in postpartum periods, and the median follow-up period was 46.5 months. In terms of pregnant patients, three had a preterm delivery, and four terminated their pregnancy, and we performed conization in one and hysterectomy in seven patients. In terms of screening results, among eight patients with NILM, the mean duration for ICC diagnosis was 10.7 months, seven had stage IB1 or worse disease, and one was dead. On the other hand, among ten women with abnormal cytological findings, the mean duration for ICC diagnosis was 1.4 months, and six had stage IB1 or worse disease, and one was dead.

Conclusions These outcomes suggest that temporary cytological screening during the first trimester of pregnancy is not useful, and clinicians should recommend HPV vaccination and routine cancer screening.