Antenatal lower genital tract infection screening and treatment programs for preventing preterm delivery
Abstract
Background
Preterm birth is birth before 37 weeks' gestation. Genital tract infection is one of the causes of preterm birth. Infection screening during pregnancy has been used to reduce preterm birth. However, infection screening may have some adverse effects, e.g. increased antibiotic drug resistance, increased costs of treatment.
Objectives
To assess the effectiveness and complications of antenatal lower genital tract infection screening and treatment programs in reducing preterm birth and subsequent morbidity.
Search methods
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (July 2009) and the Cochrane Central Register of Controlled Trials (The Cochrane Library 2009, Issue 3).
Selection criteria
We included all published and unpublished randomised controlled trials in any language that evaluated any described methods of antenatal lower genital tract infection screening compared with no screening. Preterm births have been reported as an outcome.
Data collection and analysis
Two review authors independently assessed eligibility, trial quality and extracted data.
Main results
One study (4155 women) met the inclusion criteria. This trial is of high methodological quality. In the intervention group (2058 women), the results of infection screening and treatment for bacterial vaginosis, trichomonas vaginalis and candidiasis were reported; in the control group (2097 women), the results of the screening program for the women allocated to receive routine antenatal care were not reported. Preterm birth before 37 weeks was significantly lower in the intervention group (3% versus 5% in the control group) with a relative risk (RR) of 0.55 (95% confidence interval (CI) 0.41 to 0.75). The incidence of preterm birth for low birthweight preterm infants with a weight equal to or below 2500 g and very low birthweight infants with a weight equal to or below 1500 g were significantly lower in the intervention group than in the control group (RR 0.48, 95% CI 0.34 to 0.66 and RR 0.34; 95% CI 0.15 to 0.75, respectively).
Authors' conclusions
There is evidence that infection screening and treatment programs in pregnant women before 20 weeks gestation reduce preterm birth and preterm low birthweights. Future trials should evaluate the effects of types of infection screening program and the costs of introducing an infection screening program.
PICOs
Plain language summary
Antenatal lower genital tract infection screening and treatment programs for preventing preterm delivery
A genital tract infection during pregnancy can cross into the amniotic fluid and result in prelabour rupture of the membranes and preterm labour. Such infections include bacterial vaginosis; chlamydial, trichomonas and gonorrhoeal infections; syphilis and HIV, but not candida. Preterm birth (before 37 weeks of gestation) is associated with poor infant health and early deaths, admission of the newborn to neonatal intensive care in the first few weeks of life, prolonged hospital stay and long‐term neurologic disability including cerebral palsy.
The present systematic review found that a simple infection screening and treatment program during routine antenatal care may reduce preterm births and preterm low (below 2500 g) and very low (below 1500 g) birthweights, from only one identified controlled study. The study was of high methodological quality and reported on 4155 women randomly assigned either to an intervention group where the results of infection screening were reported or a control group where the results of the vaginal smear test were not reported. The simple infection screening reduced preterm births from 5% of women in the control group to 3% in the intervention group. The number of low birthweight preterm infants and very low birthweight infants were significantly lower in the intervention group than in the control group. Neonatal morbidity or deaths in the hospitalisation period were not reported. No adverse effects were reported for the pregnant women during the treatment. Women in the intervention group who were found to have vaginal infection received standard treatment and blinding of the treatment was not possible. The obstetricians may, therefore, have provided a different level of care to women in whom an infection had been identified compared with the control group.
