Reducing the rate of preterm birth through a simple antenatal screen-and-treat programme: a retrospective cohort study

Abstract

Objective: To assess whether a simple screen-and-treat strategy in pregnancy, previously tested in a randomised controlled study, also effectively lowers the rate of preterm delivery under real-life conditions.

Study design: In a retrospective cohort study, data were enrolled of 2986 women with singleton pregnancies presenting for routine antenatal care between 11 and 24 weeks and registering for delivery. Data of 1273 women in the intervention group were collected between 1 September 2004 and 31 August 2005. The data of 1713 women in the control group had been collected 2 years previously. All women were screened for asymptomatic vaginal infection using Gram stain, differentiating between bacterial vaginosis, vaginal candidiasis, trichomoniasis, or combinations of any of the three. Women with infection received standard treatment and follow-up. Prenatal care was the same for women in the intervention and control groups, the only difference being the absence of screening and treating for vaginal infection in the control group. The primary outcome variable was the rate of preterm delivery at less than 37 weeks. Secondary outcome variables were preterm delivery at less than 37 weeks combined with birth weights ≤ 2500 g, ≤ 2000 g, ≤ 1500 g, or ≤ 1000 g.

Results: In the intervention group, the rate of preterm birth was significantly lower than in the control group (8.2% vs. 12.1%, p < 0.0001), as was the number of preterm infants with birth weights of 2500 g or below. Also, a significant difference between groups was found for very preterm deliveries, i.e., those occurring before 33 weeks (1.9% vs. 5.4%, p < 0.0001).

Conclusion: Integration of a simple screen-and-treatment programme for common vaginal infections into routine antenatal care led to a significant reduction in preterm births in a general population of pregnant women.