Clinical Review

UPDATE ON INFECTIOUS DISEASE

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New data elucidate the risk of recurrence for chorioamnionitis,
explore the utility of azithromycin as treatment for chorioamnionitis,
question the need for universal STI screening at the time of IUD insertion,
and highlight the benefits of chlorhexidine in preventing hospital-borne infection


 

References

The past year has seen the publication of four studies with immediate relevance for clinicians:

  • a retrospective, population-based cohort study that explores whether women who have chorioamnionitis in one pregnancy are at risk for the same type of infection in a subsequent pregnancy
  • another retrospective cohort study that assesses the clinical utility of testing for gonorrhea and chlamydia before inserting an intrauterine device (IUD)
  • an elegant primate experiment that highlights the value of azithromycin in subjects with chorioamnionitis
  • a multicenter, randomized, nonblinded trial in seriously ill patients to determine whether daily bathing with chlorhexidine-impregnated washcloths can reduce the acquisition of multidrug-resistant organisms and the incidence of hospital-acquired bloodstream infection.

CHORIOAMNIONITIS IN ONE PREGNANCY IS LIKELY TO RECUR IN THE NEXT GENERATION

Cohen-Cline HN, Kahn TR, Hutter CM. A population-based study of the risk of repeat clinical chorioamnio­nitis in Washington State, 1989–2008. Am J Obstet Gynecol. 2012;207(6):473.e1–e7.

This retrospective, population-based cohort study (Level II evidence) is one of the few to examine the risk of recurrence for chorioamnionitis, and the findings are intriguing. Women who were infected during their first delivery were 3.43 times more likely to become infected in their second delivery than women who did not have chorioamnionitis in their first pregnancy (95% confidence interval [CI], 2.67–4.42; P <.001). This association persisted even after adjustment for potential confounders, such as age, ethnicity, presence of premature rupture of membranes (PROM), and internal fetal monitoring.

Chorioamnionitis is a common affliction

This infection complicates approximately 5% of term deliveries and a significantly higher percentage of preterm deliveries. The principal causative organisms are group B streptococci (GBS), Escherichia coli and other aerobic Gram-negative bacilli, both Gram-positive and Gram-negative anaerobes, and genital mycoplasmas.

The main risk factors for chorioamnio­nitis are:

  • prematurity
  • prolonged labor
  • prolonged rupture of membranes
  • multiple internal examinations
  • internal fetal monitoring
  • low socioeconomic status
  • preexisting genital tract infection (eg, bacterial vaginosis, GBS colonization).

Infants delivered to infected mothers are at increased risk for sepsis, pneumonia, and meningitis. Severely infected infants, particularly those who are premature, are also at increased risk for cerebral palsy.

Details of the study

This investigation focused on women in Washington State who had a first pregnancy from 1989 through 2008 and then had at least one additional birth during the study period.

Participants included 6,219 women who had chorioamnionitis in their first pregnancy and 25,294 women who did not. Using logistic regression, Cohen-Cline and colleagues estimated the odds ratio for chorioamnionitis in the second delivery, taking into account the following potential confounders:

  • maternal age
  • ethnicity
  • presence of PROM
  • use of internal monitoring
  • smoking.

As I stated above, women who had chorioamnionitis in their first pregnancy were 3.43 times as likely to have it again in their second pregnancy.

What this EVIDENCE means for practice
When a patient has a history of chorioamnionitis, we should do everything possible to reduce her risk for recurrent infection. For example, we should screen her for lower genital tract infections that predispose to chorioamnionitis:
-gonorrhea
-chlamydia
-bacterial vaginosis
-GBS.

If the patient has any of the first three infections, treat her immediately with the appropriate antibiotics. If she is colonized with GBS, administer one of the intrapartum antibiotic regimens recommended by the Centers for Disease Control and Prevention (CDC).

If the patient has a history of preterm PROM or spontaneous preterm delivery, initiate prophylaxis with progesterone and assess her cervical length periodically to determine whether cerclage is indicated.

During labor, make every effort to minimize the duration of ruptured membranes, the length of invasive monitoring, and the number of internal vaginal examinations.

At the earliest sign of intra-amniotic infection, treat the patient with broad-spectrum antibiotics, usually ampicillin plus gentamicin.

In low-risk populations, universal screening for sexually transmitted infections is probably unnecessary before IUD insertion

Sufrin CB, Postlethwaite D, Armstrong MA, et al. Neisseria gonorrhea and Chlamydia trachomatis screening at intrauterine device insertion and pelvic inflammatory disease. Obstet Gynecol. 2012;120(6):1314–1321.

This retrospective cohort study (Level II evidence) focused on women who had an IUD inserted in a managed-care practice at Kaiser Permanente of Northern California during a 5-year period. Sufrin and colleagues compared the incidence of pelvic inflammatory disease (PID) within 90 days after insertion among women who were, and were not, screened for gonorrhea and chlamydia.

Among 57,728 IUD insertions, 47% involved women who were unscreened within 1 year of the procedure. Among women who were screened, 19% were tested on the day of IUD insertion.

The overall risk of PID in the study cohort was very low—0.54% (95% CI, 0.48–0.60). Investigators were unable to identify any significant difference in the risk of PID between women who had no screening versus those who were screened. Among women who were screened, same-day screening was equivalent to prescreening.

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