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Bacterial Vaginosis (BV) has been associated with a two or three times increased rate of preterm labor and delivery, urinary tract infections (UTIs), premature rupture of the membranes (PROM) and endometritis.(10) Because about 50% of women show no symptoms, universal screening for BV was proposed over a decade ago. (Screening and treatment is a current World Health Organization recommendation.) Screening is simple and there are several effective prescription treatments. But BV has a tendency to recur and is sometimes resistant to chemical treatment.
However, women may be able to discourage BV with some simple home methods. Numerous studies have shown that when natural vaginal Lactobacilli levels drop, BV invades.
Lactobacilli inhibit the growth of Mobiluncus, Gardnerella vaginalis, Bacteroides and anaerobic cocci even in a Petri dish.(11) Colonizing (or recolonizing) with Lactobacilli is key to vaginal health. According to Skarin and Sylvan, “The paucity of vaginal Lactobacilli is pivotal in allowing overgrowth of many other organisms of the vagina.”(12) Lactobacilli grow best in an acidic environment. A healthy vagina is acidic and naturally resists infection by “bad” bacteria—including strep.
In fact, pH alone—the acid/alkaline level measured by nitrazine or litmus paper—is a marker for prematurity risk. Retrospective and prospective studies show that high vaginal pH (a low acid, or alkaline, state) is predictive of preterm labor and preterm rupture of membranes. Viehweg, et al. state: “Measurements of the vaginal pH value are able to verify an alkalization of the vagina caused by atypical vaginal flora…In contrast to normal pregnancies there is a relation between a pathological pH value > 4.5 and consequent preterm birth in pregnancies with preterm labor.”(13) In the Multicenter Bacterial Vaginosis (BV) Trial—a prospective study—21,554 women were screened for vaginal pH and outcome. Women with a vaginal pH of 5.0 or greater had a significantly increased risk of preterm birth and/or low birth weight.(14)
Several alkaline organisms other than Gardnerella (BV) are implicated in PROM. Women with high levels of these alkaline-producing bacteria had over 300% increases in rate of PROM. In an article on pPROM, Ernest, et al. note: “Numerous infectious organisms that change the normal vaginal milieu have been associated with preterm PROM. Because these organisms alter vaginal pH, the use of pH was evaluated as a potential marker for women at increased risk for preterm PROM… Those with a mean vaginal pH above 4.5 had a three-fold increased risk of preterm PROM as compared with those with a mean pH of 4.5 or lower.”(15)
Testing pH level is simple, fast, inexpensive and non-intrusive. Women can do it themselves by touching a strip of nitrazine paper to their vaginal walls. Nitrazine or litmus paper is available at most drug stores. The urine test strips used by most midwives also assess pH.