Most obstetricians believe that multiple cervical examinations during labor may increase the risk of intra-amniotic infection and fever. There is very little evidence to support this perception. Because available studies have not used time-dependent analyses to estimate the risk between increasing number of cervical examinations and fever, it is unknown whether the risk factor for a specific febrile patient is the length of labor, the number of examinations, both, or neither.
This retrospective cohort study was designed to estimate the risk of increasing numbers of cervical examinations with maternal fever in labor and delivery. Time-dependent analysis was used to investigate whether changes in the length of labor and length of membrane rupture were risk factors for infection. The study was conducted over 4 years at a university medical center. Participants were 2395 women with singleton term pregnancies (≥37 weeks of gestation) who reached the second stage of labor and were afebrile on admission. Women who developed an intrapartum fever were compared with women who were afebrile through 6 hours postpartum. The primary study outcome measure was maternal fever. Extensive labor and delivery data were obtained from medical records, including obstetric and medical history, admitting diagnoses, number and timing of cervical examinations, and neonatal and maternal birth outcomes. Cox proportional hazard models were used to assess risk of fever, adjusting for potentially confounding factors. Cervical examinations were performed 1 to 14 times.
Of the 2395 women afebrile at admission, 174 (7.2%) developed an intrapartum fever. A greater number of examinations was not associated with increased risk of fever. There was no significant difference in the risk of fever between women who had 1 to 3 cervical examinations and those with 7 or more examinations; the hazard ratio was 0.9, with a 95% confidence interval of 0.4 to 2.0. Stratification of the data by labor type did not show a significant association between the number of cervical examinations and risk of fever. Moreover, the number of cervical examinations performed after rupture of membranes was not associated with a statistically significant increased risk.
These findings show that the number of cervical examinations performed in pregnant women during term labor management is not an independent risk factor for maternal fever during the second stage of labor.
Department of Obstetrics and Gynecology, Washington University in St Louis, St Louis, MO.