Study population and design
This was a prospective interventional study that commenced in October
2016. The Kyushu University Hospital Ethical Review Board approved the
study, and all work was conducted in accordance with the Declaration of
Helsinki (1964). The enrollment criterion was women with singleton
pregnancies after the second trimester who had previously undergone AT
for early-stage uterine cervical cancer at our hospital. The exclusion
criteria were abortion during early pregnancy, contraindications for
progesterone use, multiple pregnancies, women who had undergone AT in
other hospitals, and fetuses with severe anomalies or abnormal
chromosomes. Eligible women were invited to participate in this study
and sign a consent form. After obtaining informed consent, we started
vaginal progesterone administration.
The primary outcomes of our study were gestational age at delivery and
the incidence of preterm birth before 37 weeks and 34 weeks of
gestation. The secondary outcomes were the incidence of pPROM and other
obstetric complications, maternal adverse events (transfusion for
massive vaginal bleeding, hysterectomy after cesarean section, septic
shock, and maternal death), and neonatal morbidity and perinatal
mortality (fetal death and neonatal death).
We investigated these outcomes
among the study participants and compared them with those of the
historical control group participants. The historical control group
included women with singleton pregnancies after AT who were managed
without VP at our institution between
January 2007 and September 2016.
Data of the historical control group participants were collected
retrospectively by reviewing both maternal and neonatal medical records
of each participant. In 2017, we reported the perinatal outcomes of
singleton pregnancies after AT18 managed between March
2005 and October 2015, and the historical control group in this study
partly overlapped with that reported in the previous study.