A comparison of aztreonam and two regimens of gentamicin in a rabbit model of intra-amniotic infection and sepsis.

OBJECTIVE: To compare aztreonam in a standard dose with two gentamicin doses in the early treatment of experimental intra-amniotic infection in rabbits induced by intracervical inoculation with Escherichia coli. METHODS: Timed pregnant rabbits on day 21 (70% of gestation) were inoculated intracervically with 10(4)-10(5) colony-forming units of E coli. After inoculation, the animals were treated with one of three regimens: 1) aztreonam at 90 mg/kg/day ("standard" dose in humans), 2) gentamicin at 4.5 mg/kg/day ("standard" dose in humans), or 3) higher-dose gentamicin at 6.0 mg/kg/day, each given in three divided doses daily. Outcomes included fever, delivery, and presence of a live fetus. At necropsy, cultures were taken from endometrium, amniotic fluid, and blood. Data were analyzed by Fisher exact test because the expected cell size was fewer than five. RESULTS: Compared with rabbits treated with aztreonam, those treated with gentamicin 4.5 mg/kg/day delivered significantly more often (P = .002), had more positive cultures (P < .001), and had significantly fewer live fetuses (P < .001). Compared with rabbits treated with gentamicin 6.0 mg/kg/day, those treated with gentamicin 4.5 mg/kg/day delivered more often (P = .003), had fewer live fetuses (P = .02), and had more positive cultures (P = .02). There were no significant differences between the aztreonam and gentamicin 6.0 mg/kg/day groups. CONCLUSIONS: This study demonstrates in an animal model that aztreonam and gentamicin at 6.0 mg/kg/day are more effective than gentamicin at 4.5 mg/kg/day (a dose that is widely used empirically in humans) in the early treatment of experimental intra-amniotic infection in rabbits. Aztreonam was as effective as gentamicin at 6.0 mg/kg/day. In this rabbit model, in which intra-amniotic infection is accompanied by maternal sepsis, 4.5 mg/kg/day of gentamicin was not adequate for the treatment of severe maternal infection.

A prospective study of heparin-induced osteoporosis in pregnancy using bone densitometry.

OBJECTIVE: Our purpose was to evaluate the subclinical occurrence of heparin-induced osteoporosis in pregnancy, by means of bone densitometry. STUDY DESIGN: A prospective, consecutive cohort of 14 pregnant women requiring heparin therapy and 14 pregnant controls matched for age, race, and smoking status was identified by 20 weeks' gestation at a university medical center. Proximal femur bone density measurements were taken at baseline, immediately post partum, and 6 months post partum in the cases and controls. Vertebral measurements were also obtained on both groups immediately post partum and 6 months post partum. Bone density as a function of heparin dosing and duration was examined. Nonparametric statistical tests were used for all comparisons. RESULTS: Five of 14 cases (36%) had a > or = 10% decrease from the baseline proximal femur measurements to immediate postpartum values versus none of the 14 matched controls (p = 0.04). Mean proximal femur bone density measurements also decreased in the cases (p = 0.01); this difference continued to be statistically significant 6 months post partum (p = 0.03). No dose-response relationship could be demonstrated. CONCLUSION: Heparin adversely affected bone density in about one third of exposed patients.

Life-threatening puerperal infection due to group A streptococci.

We describe two patients with life-threatening puerperal infection due to group A beta-hemolytic streptococcus. Each patient had bacteremia, shock, and multi-organ involvement. Both cases were compatible with a recently described streptococcal toxic shock-like illness. Both women failed to improve despite vigorous medical and antibiotic therapies, and each required hysterectomy. Obstetricians should be alert to the importance of early diagnosis and treatment of this potentially lethal infection.

Vaginal birth after cesarean section in a small hospital.

Most studies on vaginal birth after cesarean section come from medical centers or university hospitals. However, the minority of births in the United States occur in these hospitals. When compared with larger institutions, many small hospitals have longer operating start-up times, less adequate blood banking facilities, and decreased obstetrical anesthesia support. Over a 30-month period in a small hospital, a trial of labor was successful in 76% of patients with prior cesarean section. Despite the limitations of support in a small hospital, vaginal birth can be offered to selected patients with prior cesarean section delivery. In our experience, vaginal birth after cesarean delivery requires significantly more physician hours in the hospital than does repeat cesarean section. The problem of a pregnancy with a prior cesarean section is an ever-increasing one and, in our practice, approximately 25% of multiparous patients have had a prior cesarean delivery.