Objective: Uric acid is known to be elevated in preeclampsia. We sought to determine if uric acid levels on admission correlate with the length of expectant management in preterm patients with preeclampsia.
Study design: A retrospective chart review was conducted on singleton preeclamptic pregnancies delivered between 24 0/7 and 37 0/7 weeks' gestation at Tufts Medical Center between January 2005 and December 2007. Patients with a multiple gestation and those transferred or discharged before delivery were excluded. Data regarding signs and symptoms of preeclampsia, laboratory values, pregnancy complications and outcome were abstracted from the medical records. Correlation between admission uric acid level and days of expectant management was assessed. The relative risk (RR) was used to estimate the effect of uric acid levels on expectant management length >7 days. Mantel-Haenszel χ(2) values were used to construct 95% confidence intervals (CIs) around the RR.
Result: Four hundred seventy-one charts were reviewed. Of these, 190 met inclusion criteria. In all, 55 patients (28.9%) were managed expectantly for >1 week. Admission uric acid level correlated with days of expectant management (P<0.0001). Uric acid levels at admission were categorized as ≤4.0 mg dl(-1) (low uric acid level), 4.1 to 6.0 mg dl(-1) (medium) and ≥6.1 mg dl(-1) (high). Relative to women with high uric acid levels at admission, we observed a sevenfold higher rate of extending expectant management for >1 week among women with low uric acid level (7.0; 95% CI: 3.34 to 14.68). Women with medium uric acid levels at admission also had a higher likelihood of prolonging pregnancy relative to women with high uric acid levels (RR: 2.81; 95% CI: 1.32 to 5.96) (P-value for trend <0.0001).
Conclusion: Admission uric acid levels correlate with the length of expectant management in preterm patients with preeclampsia. Pregnancy prolongation for >1 week is significantly more likely in patients with low and medium uric acid levels at the time of admission. Uric acid levels may be helpful in assessing disease severity and counseling preeclamptic patients regarding likelihood of extended expectant management.