Benign fever following vaginal delivery.

BACKGROUND

In patients with fever following vaginal delivery, physicians must differentiate benign self-resolving fevers from fevers with more serious causes, especially endometritis. To help differentiate these clinical entities, we explored the characteristics and risk factors for benign "single-day" postpartum fever.

METHODS

We conducted a retrospective cohort study of 2137 vaginal deliveries. Patients were randomly selected from the 25,687 vaginal deliveries that took place between 1979 and 1992 at The University of Iowa Hospitals and Clinics. The data were analyzed using odds ratios and multiple logistic regression.

RESULTS

Benign fevers occurred in 3.3% of patients, while endometritis was diagnosed in 1.6%. After controlling for confounding variables, two clinical factors were independently associated with single-day fever: primiparity (odds ratio [OR], 3.4; 95% confidence interval [CI], 2.0 to 5.7) and use of a uterine pressure catheter (OR, 2.4; 95% CI, 1.5 to 3.7). These factors were not associated with endometritis. The first postpartum temperature elevation ( > or = 38.0 degrees C) occurred earlier in patients with single-day fever than in patients with endometritis (4.0 +/- 4.6 hours postpartum vs 30.2 +/- 27.0 hours postpartum, P < .001). The maximum temperature elevation was lower, on average, in patients with single-day fever than in patients with endometritis (38.2 degrees +/- 0.2 degrees C vs 38.9 degrees +/- 0.6 degrees C, P < .001).

CONCLUSIONS

Single-day fever was more likely to occur in primiparous women and in women who were monitored with a uterine pressure catheter. Most women with benign single-day fevers had early low-grade fevers, whereas women with endometritis had higher fevers that occurred later in the postpartum period.