Including Gram's stain screening for asymptomatic vaginal infection in an early second-trimester routine prenatal visit can reduce the rate of preterm delivery by about 44%, according to the results of a recent prospective, randomized, controlled trial conducted in Austria. 

Researchers included over 4,000 pregnant women presenting to non-hospital-based antenatal clinics for routine prenatal visits. They provided the results of the vaginal smears for women in the intervention group to their caregivers, who, in turn, provided standard treatment and follow-up for any detected infections. That included oral or topical clindamycin for bacterial vaginosis, local clotrimazole for candidiasis, and topical metronidazole for trichomoniasis. The researchers did not provide test results, however, to caregivers of women in the control group.  

The rate of preterm births (less than 37 weeks) was 3% in the intervention group versus 5.3%  in the control group (95% confidence interval  1.2 to 3.6; 

=0.0001). The rate of preterm infants with a birthweight of 2,500 g or less in the intervention group was half (1.7%) that in the control group (3.5%) (

= 0.0002). The rate of late miscarriage was also reduced by 50%. 

Including Gram's stain screening for asymptomatic vaginal infection in an early second-trimester routine prenatal visit can reduce the rate of preterm delivery by about 44%, according to the results of a recent prospective, randomized, controlled trial conducted in Austria.