A RANDOMIZED TRIAL OF 3 ANTIBIOTIC REGIMENS FOR THE TREATMENT OF PYELONEPHRITIS IN PREGNANCY

Objective: To compare the effectiveness of three antibiotic regimens f or the treatment of acute pyelonephritis in pregnancy. Methods: One hu ndred seventy-nine pregnant women earlier than 24 weeks' gestation who had acute pyelonephritis were randomized to 1) intravenous (IV) ampic illin and gentamicin, 2) IV cefazolin, or 3) intramuscuIar ceftriaxone . All participants then completed 10-day courses of oral cephalexin af ter primary treatment. A urine culture was performed on admission and 5-14 days after completion of therapy. Surveillance for persistent or recurrent infection and obstetric complications continued until delive ry. On the basis of a two-sided hypothesis test and with alpha = .025, 60 subjects were needed in each group for statistical power greater t han 80% to detect a difference between ceftriaxone and other antibioti cs if hospital length of stay differed by 1 or more days. Results: The treatment groups were similar in age, parity, emperature, gestational , age, and initial white blood cell count. There were no statistically significant differences in length of hospitalization, hours until bec oming afebrile, days until resolution of costovertebral angle tenderne ss, or infecting organism. There were no statistically significant dif ferences in birth outcomes between the three groups. The average (stan dard deviation) age at delivery was 38.8 +/- 3.6 weeks. The average bi rth weight was 3274 +/- 523 g. Eleven (6.9%) of 159 subjects delivered prematurely. Escherichia coli was the most common uropathogen isolate d (137 of 179, 76.5%). Blood cultures were positive for organisms in 1 5 cases (8.4%). At follow-up examination within 2 weeks of initial the rapy, eight (5.0%) of 159 subjects had urine cultures positive for org anisms. Ten women (6.3%) had cultures positive for organisms later in their antepartum course, and 10 other participants (6.3%) developed re current pyelonephritis. Conclusion: There are no significant differenc es in clinical response to antimicrobial therapy or birth outcomes amo ng subjects treated with ampicillin and gentamicin, cefazolin, or ceft riaxone for acute pyelonephritis in pregnancy before 24 weeks' gestati on. (Obstet Gynecol 1998;92:249-53. (C) 1998 by The American College o f Obstetricians and Gynecologists.).