Pre-term birth usually associated with low birth weight of the infant is one of the most important risk factors associated with cerebral palsy. Although pre-term birth accounts for only 12% of all live births, it is associated with 40% of infants with cerebral palsy. Thus, the causes of pre-term birth and steps to prevent it are important subjects of cerebral palsy research.

Bacterial infection of the pregnant woman's vagina (bacterial vaginosis), often with no maternal symptoms of illness, affects about 800,000 pregnant women per year in the U.S.A. Women with bacterial vaginosis are more likely than other women to have a pre-term delivery (less than 37 weeks) or a low birth weight infant (under 5.5 lbs). If treatment of bacterial vaginosis was to reduce the occurrence of pre-term delivery, the risk of infants born with cerebral palsy would be significantly lessened.

A group of investigators evaluated the usefulness of antibiotic treatment of pregnant women who had bacterial vaginosis and a prior history of pre-term delivery.¹ The investigators found no benefit of this treatment in either reducing the occurrence of premature delivery or of preventing injury to the infant.

Comment:
Needless to say, the results of this study were a great disappointment. An editorial in the same journal evaluated the reasons for what might appear to have been the reason (s) for the failure. Was the population studied similar to the general population of the USA? Probably not; the population was a very high-risk population. Was the antibiotic given too late in pregnancy? Probably. Should both intravaginal antibiotics and oral antibiotics have been used? Probably. As often happens, failure in a study leads to a sharpening of the methodology that needs to be used and generally leads to a second, more precise study. This may happen.

For the time being, the Public Health Service's recommendation continues to stand: women who have symptomatic bacterial vaginosis during pregnancy should be evaluated, the specific organism identified and specific therapy used. The research issues are what to do about women who have no symptoms? Are there special groups of infected women who have no symptoms but are at high risk of premature delivery? How are they to be identified? When should they be treated; probably the earlier the better. How should they be treated?

The present unsuccessful study gives us information on how to better answer these questions. We hope the next study will be developed and these questions answered.

¹ Carey, J. Christopher et al. Metronidazale to Prevent Preterm Delivery in Pregnant Women With Asymptomatic Bacterial Vaginosis. NEJM 2000; 8: 534-540

© UCP Research & Educational Foundation, June 2000

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