Evidence-based Prevention of Preterm Birth and Rupture of Membranes: Infection and Inflammation

Abstract

Prevention of preterm birth and subsequent newborn immaturity is a primary goal of health care in Canada and throughout North America. Much accumulated evidence shows that (I) as many as 30 to 50 percent of preterm births are caused by common genital tract infections and subsequent maternal/fetal inflammatory responses; (2) microbial and maternal host factors (phospholipases, proteases) play roles in preterm labour and preterm premature rupture of membranes (pPROM); (3) identification and systemic treatment of common genitourinary infections, most importantly bacterial vaginosis (BV), reduces risks of preterm delivery and PROM; and, (4) antimicrobial treatment with erythromycin, clindamycin or other antibiotics can significantly delay delivery and reduce the risks of maternal and neonatal morbidity as well as reduce the risk of early onset group B streptococcal sepsis in women with pPROM or preterm labour prior to 34 completed weeks gestation.Diagnosis of EV can be made inexpensively and accurately by using Amsel’s clinical criteria: homogeneous discharge, pH ≥4.5, positive amine test, and “clue” cell identification (3 of 4). Optimal treatment for BV during pregnancy is either prompt administration of oral metronidazole or clindamycin followed by a “test of cure” evaluation and retreatment as necessary. Screening and treatment for BV and other prevalent reproductive tract infections and bacteriuria are most easily and effectively performed during the initial antepartum visit. Screening and treatment can be repeated at 20 or 28 weeks gestation in patients judged at risk for repeated infection. Partners of women with sexually transmitted diseases should be treated; both patients and partners should have “tests of cure.” Both asymptomatic and symptomatic infections should be treated. Potentially powerful interactions of reproductive tract infection and inflammation with other obstetric factors, including a prior history of preterm birth, first trimester bleeding, and possibly, short cervix and multiple gestation can be mitigated by effective treatment of reproductive tract infections. Medical care providers now have the opportunity and the obligation to reduce infection-mediated preterm birth by expeditiously identifying and treating prevalent reproductive tract infections in their pregnant patients.