Low Amniotic Fluid Raises Risk of Infection in Women With PPROM.
Even with antibiotic prophylaxis, women with a low amniotic fluid index (AFI) still have a significant risk of developing an infection and delivering prematurely, Dr. Austin Kooba reported during the South Atlantic Association of Obstetricians and Gynecologists.
It is well known that preterm premature rupture of membranes (PPROM) is associated with chorioamnionitis and neonatal sepsis, possibly as a result of the destruction of the membrane barrier and ascending infection. It has also been proposed that amniotic fluid itself has bacteriostatic properties and a decrease in fluid decreases intraamniotic immunity
Although it has been shown that a lower amniotic fluid index is associated with increased infection, no one has looked at whether a low composite four-quadrant measurement confers increased risk when routine antibiotic prophylaxis is given, according to Dr. Kooba, who is an ob.gyn resident at the Medical University of South Carolina in Charleston.
In a study involving 225 women with PPROM and a singleton gestation between 24 and 32 weeks, 131 patients had an AFI of less than 5 cm and 94 had an AFI of greater than 5 cm. The AFI was determined on admission from a four-quadrant survey. All participants received a single dose of prophylactic antibiotics--which included ampicillin, clindamycin, erythromycin, or azithromycin--as well as betamethasone.
Patients who had an abnormal fetus or a cerclage or who required obstetrical intervention such as tocolysis were excluded from the study. The women in the two groups were similar in terms of race, age, parity insurance, and group B streptococcus colonization status.
The incidence of perinatal infections was significantly higher in the low AFI group. The incidence of chorioamnionitis was 31% in the low AFI group versus 8% in the high AFI group.
Postpartum endomerritis occurred in 22% of low AFI versus 4% of high AFI patients. And 9% of the neonates in the low AFI group developed early onset neonatal sepsis versus 0% in the high AFI group.
While both groups suffered PPROM at the same gestational age, the low AFI group had a shorter latency period and thus delivered more prematurely.
And women in this group were more likely to be delivered by C-section for a nonreassuring fetal heart tracing than the high AFI group, Dr. Kooba said.
An AFI of less than 5 cm turned out to be the only risk factor associated with the development of chorioamnionitis and neonatal sepsis, he commented.
Endometritis was not significantly associated with oligohydramnios but was associated with chorioamnioniris and C-section.
"Identification of a patient with oligohydramnios after PPROM may allow for earlier and more aggressive antibiotic intervention to potentially decrease the associated perinatal infections," Dr. Kooba said.
He suggested that intravenous antibiotics with broader-spectrum agents may be appropriate but noted that this hypothesis must be tested prospectively in a randomized trial.
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|Publication:||OB GYN News|
|Date:||Apr 1, 2000|
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