We welcome the fact that even studies that did not yield positive results find their way to publication. However, to conclude from the absence of a positive result that no association exists between bacterial vaginosis (disturbance of the microbiological balance of the flora of the female genital tract) and preterm birth would be regrettable.
The negative result does not surprise me and corresponds to my own long years of experience. In addition to the substantial selection problem in this study, the following microbial causes are likely to have contributed to the negative result:
Measuring the vaginal pH captures only the number of lactobacilli and not the number of potentially pathogenic bacteria in the vagina. The pH is also raised after ingestion of antibiotics, but no bacterial disturbance is present in such a scenario, and neither is there a risk of infection.
It has been common knowledge for a long time that a disturbed vaginal flora and bacterial vaginosis, often accompanied by E coli, are among the risk factors for late miscarriage and preterm birth. In contrast to other risk factors, this cannot be detected and rectified by the patient but by her doctor.
Although metronidazole and clindamycin are mentioned as guideline-recommended first-line agents of choice for bacterial vaginosis, as studies for these substances exist only for non-pregnant women, treatment with these substances during pregnancy in order to reduce the rate of preterm births is inappropriate (1, 2). Metronidazole is problematic during pregnancy because of its interaction with DNA, and clindamycin tends to trigger an abnormal selection of E coli.
Improving the anogenital region in the long term by promoting the growth of lactobacilli by means of acidification and water-free ointments and reducing intestinal pathogens is the better method, in my experience (3). Sickness funds should commit to this treatment if they want to prevent suffering and save money.
Footnotes
Conflict of interest statement
Professor Petersen has received honoraria for speaking and continuing medical education events from Bayer, Taurus, Essex Pharma, Kaymogyn, and Grünenthal.
References
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